Heat damage to blades when grinding... [Archive] - Sawmill Creek Woodworking Community

ian maybury

10-22-2014, 5:02 PM

Brian's thread on choice of chisels just set me thinking. I'd always thought it was just that I was using cheap chisels, but it starts to look like even good quality chisels sail pretty close to the wind so far as edge damage is concerned when working hardwoods. My white steels don't much like paring plywood for example. Which while it's known to be hard on edges you would imagine might not be that bad.

Guess I'm wondering if there's perhaps not more of us than realise it cooking the edge a little when sharpening, and consequently working almost all of the time with a less than optimum steel condition?

The reason for this suggestion is that when push comes to shove the action (both sharpening and cutting) really only happens at the last thou or two of the edge. It's got to be very hard for heat to conduct itself away from an edge that fine, and equally be very easy to in just this very localised strip get up to decent temperatures without causing noticeable bluing etc.

Many of us use e.g. our finger, or water boiling off to detect heat. Which by definition requires heating quite a large area, and implies that the actual edge may be getting a lot hotter. Even taking a lot of care like I did - on a Work Sharp running at 500rpm, and cooling in water after a few seconds of grinding - and not grinding right to the edge.

There's also the possibility that even if the heat treatment of steel was spot on that factory grinding (presumably liquid cooled?) might have messed it up a bit.

Wonder has anybody ever done the metallurgical analysis to determine what actually is going on, and determined just what is permissible and what is not? I'm not all that comfortable with most dry bevel grinding options for example - but maybe I'm being over cautious...

ian

David Weaver

10-22-2014, 5:10 PM

It's pretty easy to determine practically if you're doing any damage of an appreciable amount. You can either get something like a tormek, or hand grind for a while with a norton crystolon.

I haven't seen any difference in edge holding between the first edge off of a grinder or a chisel that hasn't see the grinder for years.

I can literally put anything that I grind in my palm, though - the amount of grinding that occurs on a maintenance grind is very little and should never trouble an edge - even on a gray or brown stone (as long as said stone has been freshly dressed).

The fact that some things trouble edge is a combination of:
1) the act itself being beyond the strength of the edge (which is often a matter of a few degrees of extra bevel)
2) the act being carried out improperly, as in twisting or other than linear blows with a hammer

when you work something and you want to do something abusive while working, that's a good time to have high speed steel chisels.

Take a look under a loupe with bright light and see if you see light straw anywhere near the edge. If you don't, you've got no problems, though my practical test above is better - so long as the final bevel is equivalent on a chisel that sees a grinder and one that doesn't. that probably requires a honing guide.

Talk of burning edges has sold a lot of tormeks to beginners, but functionally, it's not a problem in the shop for anyone (or at least most) with a moderate amount of experience.

bridger berdel

10-22-2014, 5:11 PM

The flip side of this question is to ask what is happening when I badly blue a chisel on the grinder, hone it anyway and see no difference in performance. Not that this happens much, but yes, it has happened.

ian maybury

10-22-2014, 7:06 PM

That's a fair question too Bridger. Maybe the reality is just that chisels in general walk a fine line between edge failure and optimum performance.

It's early days for me on the white steel chisels David, so it's not a case of having a firm view. A coarse stone that will hand regrind bevels fairly quickly sounds like a good test. Perhaps it's because so far i've mostly been forming/re-angling bevels, but even the Shapton 120 seems a little slow though. Wonder if a coarse Crystolon would do any better?

I have a Tormek too, and it works very well - but haven't so far got serious about finding a solution to the problem of how to accurately flatten/dress the sides of the stone (my chisels are sharpened single bevel - so i don't use the wheel in the normal format as i don't want hollow bevels) - and how to align tools. A horizontally mounted Tormek would be great, but then there's the issue of handling the water. Plus I like to be able to use a honing guide when forming the primary bevel as on the top surface of the WorkSharp. That's more or less Makita territory, but realistically I don't want to buy another grinder so it's probably down to finding a way to re-configure the Tormek.

Surprised that somebody hasn't done it already….

Ron Brese

10-22-2014, 7:26 PM

It's usually recommended that when grinding a tool that's been previously honed that you don't grind all the way thru the edge and leave a small line of the polished edge unground. When you put this tool bevel back on the honing stones you work thru the polished edge that's left and pull a burr quite quickly. This of course serves a couple of purposes. It keeps you from cooking the fine edge and you also don't have to hone away the coarse grinding scratches. Using this method the edge just becomes more refined each time you work the iron.

Ron

David Weaver

10-22-2014, 10:08 PM

Those side wheels on the tormek will get tired pretty quickly.

The reality with japanese chisels is that you should work with them until you are not getting any damage that can't be removed easily with a medium stone (like 1k type stone) and very quickly.

You can hollow grind them fine with the tormek, but it's unsightly.

You can hollow grind them on a dry grinder if you can keep them below about 125C but it's generally not needed, and anyone who will burn an O1 tool will burn white steel earlier, or at least draw out some of the temper.

I have dry ground white steel irons with the pink wheel with no issue and no noticeable loss of hardness, but I do that only when I get a used iron that is in serious disrepair (which includes things like having a big rounded bevel on the back).

Bruce Mack

10-23-2014, 3:59 AM

I am reluctant to get a grinder to prep my irons for waterstones. #1 reason is cowardice--I expect my learning curve would result in trashing a few favorite blades, even starting with a sacrificial iron from, say, a Home Depot loser. #2 is the expense of a new shop machine with its necessary berthing on a table/bench that is already crowded,
Like Ian, I use a Shapton 120, but chiefly to flatten the bevel using the side sharpening technique to take the belly out after "excessive" rounding from my freehand sharpening. This works well and fast. For my LV low angle bevel up smoother I have several blades, 25 and 38 degrees, so don't see a need for further angle adjustments as would be facilitated with a grinder. My Precious is the LN 4 1/2 bevel down with 45 degree frog. With cap iron set close it seems to handle all domestic woods I use. No back bevel for that baby.
Just an amateur's view.

ian maybury

10-23-2014, 6:11 AM

Thanks Ron, David. My view is strictly amateur too Bruce. I'm very much at the getting to know you stage with both the waterstones and white steel chisels, and have just come off a major back flattening and bevel setting exercise which has probably coloured my perceptions on how long it all can take a bit. I also ended up having to reset the bevel angle on three very thick 50 deg Lee Valley O1 and A2 BU planes irons bought some years ago before the realisation had dawned that the 25deg does most jobs, and that steeper cutting angles and cambers are best put on over that in the form of a micro bevel. This turned out to be very hard work indeed, even using an 80grit sanding disc for heavy metal removal - although it was entirely down to my making bad buying choices. The quality of the LV BU blades is actually incredibly good.

I'm relatively well aware of the practice of not grinding back through the bevel when re-honing Ron - although i had no choice but to do so given the pretty haphazard (too shallow) bevel angles on some of the chisels to be brought back to 30deg. Against that I took a lot of care on the WorkSharp as above - what most would regard as OTT.

I guess the question about heat damage was intended more to explore the question of whether or not in situations like this (since so many report fairly rapid edge degradation, even on good chisels) it's posible that we unwittingly disturb the heat treatment in a micro zone right at the edge when shaping the bevel - even using what are normally regarded as conservative and acceptable methods such as those you describe David. Or that (as seems well accepted) the makers sometimes do when grinding - it's not unusual to hear reports of this.

Either way as both yoursef and Ron suggested earlier the proof on that particular one will likely emerge with successive re-honings.

On grinding solutions David. It sounds like your experience (and the common wisdom) is that it's possible to use any of the above methods provided care is taken and the edge is not cooked - with the underlying point being that now that the tools are set up grinding will be a very rare requirement anyway. That said i guess i'd have been dead pleased if somebody had piped up to say 'use an xyz stone, that's really quick' - that there is a wet manual (safe) option about that cut fast enough to be an alternative when there's a lot of metal to come off...

I did fine with the 80grit sanding disc on the wide and thick plane blades - switching back to the WorkSharp once the edge started to thin a bit to head off the risk of overheating. Very easy to overdo it though - as Bruce dry power grinding makes me nervous. Seems like it's just another skill to be refined for use when appropriate. The Tormek likewise works as a route, but is surpisingly slow. Ditto the 120 grit Shapton. When blade thickness and width (volume of metal to be removed) come into play there doesn't really seem to be a one size fits all solution except perhaps a surface or similar toolroom wet grinder...….

Kees Heiden

10-23-2014, 7:01 AM

It's probably inevitable that you overheat a narrow part of the edge on the grinder. All those sparks indicate pretty high temperatures. But that's one reason why we continue on a whetstone. You remove that overheated layer quick enough. I don't find that I loose hardness, not even in the white steel Japanese chisels.

Jim Matthews

10-23-2014, 7:42 AM

I use the Knife grinding set from Lee Valley, with the 1" belt running vertically.

It's only needed on the most badly damaged blades.
I keep a coffee can of water to dunk the blade,
every few passes.

Haven't taken the temper off any steel, yet.

Start with a medium grit belt, or charged leather belt
if you're concerned about overdoing things.

FYI - It's the means by which I reliably camber plane irons, too.

David Weaver

10-23-2014, 7:48 AM

I have never used the worksharp, so I don't know what it does to burn things. The two fastest burns I have ever seen, or three, I guess are:
1) high speed belt grinder with a hard platen - you will get extreme heat at the contact point if you use any pressure on anything but fresh abrasive. Instant blue
2) disc sander (seemed like a good idea, but probably the hard platen thing again)
3) a fine grit wheel on a bench grinder

As far as changing a bevel from 50 to 25 degrees, that's a lot of work no matter how you do it. The fastest thing I can think of with low heat is a cheap belt sander with really coarse grit - no super tight belt over a hard steel platen. But once you do that grind once, you never do it again. A coarse wheel on a bench grinder is a better compromise.

Far as the side of the tormek wheel (maybe I said this or maybe I missed it earlier), they go to sleep pretty quickly, and if you try to put a diamond hone against the side of the wheel it will just eat the hone (i've tried it). You'd probably have to take the tormek wheel off and rub it on a sheet that was covered with loose abrasive that is very coarse. Like 40 or 60 grit silicon carbide.

The alternative is to hold something like this against the wheel, but it would take a while to do the whole wheel:

http://www.amazon.com/POWERTEC-71003-Diamond-Grinding-Dresser/dp/B00B10LM6O/ref=sr_1_1?ie=UTF8&qid=1414064698&sr=8-1&keywords=diamond+dresser

(I've been using a dresser of that style for 6 or 7 years now on the bench grinder, and I was sure that it wouldn't last very long, but it's held up well and I'm still using the same one, and I used it on the tormek a little bit, too, though it's a bit coarse for that).

Ian - the comment about just having experience is correct. I think you'll (if you want to grind with a bench grinder) gravitate toward a coarse wheel that is either soft or that is hard but that is dressed often, and you won't even see temper colors near the edge of anything, let alone blue. You won't be able to do this correcting a bevel, but in my opinion, maintenance grinding on anything results in a tool that you can put into your palm after you grind it if the wheel is coarse enough and dressed well enough.

ian maybury

10-23-2014, 9:20 AM

Sounds like the potential micro burning issue is a dead duck anyway - if only because it's easy to hone away as you guys say.

I can agree about the fast burning scenarios - but despite this as above did fine on the early stages of heavy metal removal re-angling the bevels on the plane blades on a sanding disc on 80 grit AlOx. It'd burn the edge or a corner in a moment once it starts to thin down towards the edge though. Keeping the entire area of the bevel in contact at all times is important too to stop burning - i used a honing guide off a DIY perimter table. I did one on a Bosch variable speed belt sander with 80g AlOx - the 200m/min variablke speed gives good control, but it needs the right platen and flush jointed belts. I also hollow ground a plane iron on the Tormek, and then flattened the bevel on the WorkSharp - works OK too, but slower.

I managed to demolish a diamond plate trying to dress the Tormek wheel too. :) Tormek do a carborundum dressing stone too which might work. Or maybe set up their screw fed point diamond in an appropriate way. I haven't done anything about trialling a set up to use the side of the wheel as a primary flat bevel grinder because it's a bit slow and apart from the water didn't seem to bring a lot to the party.

The Worksharp (working with a honing guide off the accessory top surface/table) actually does a very decent job. A slowish surface speed (around 500ft/min) means it doesn't heat all that much if the abrasive is kept fresh (you would have to be heavy handed to do harm), and the level of aggression is about right for chisels. It's very slow to remove significant amounts of metal from a plane blade though. The self adhesive abrasive discs get very expensive over here, and diamond discs while cooler are probably not a great deal more cost effective as they don't last as I had hoped. (on heavier jobs like plane blades anyway)

The one size fits all primary bevel grinding solution (capable of forming a plane bevel as well as doing maintenance grinding right down to small chisels) remains elusive it seems, especially when the preference for a flat bevel is factored in…. (low speed bench grinders with soft wheels sound like a candidate if a hollow grind is OK)

lowell holmes

10-23-2014, 9:33 AM

I have a variable speed bench grinder, but seldom use it.

If I need to re-grind a chisel, I will put it in a honing guide and turn a belt sander upside down in a bench vise, and then grind it on the belt.

Afterwards, it will be honed in 3 grades of diamond hones. After stropping on mdf charged with green honing compound, the bevel is mirror finish.

This is the only time I use honing guides.

David Weaver

10-23-2014, 9:41 AM

The one size fits all primary bevel grinding solution (capable of forming a plane bevel as well as doing maintenance grinding down to small chisels) remains elusive it seems, especially when the preference for a flat bevel is factored in…. (low speed bench grinders with soft wheels sound like a candidate if a hollow grind is OK)

Use of a bench grinder with coarse wheels satisfies everything except the flat grind. There is no real advantage of such a flat grind, though, and with the smallest of chisels (less than 1/4" and even those), it may make just as much sense to hone those without grinding.

A knife grinder/belt grinder would also work instead of a bench grinder if you want a flat bevel and are willing to keep a coarse abrasive belt on it and learn where you can finesse it to avoid burning.

ian maybury

10-23-2014, 10:35 AM

That's the way my train of thought is headed too - but so far I'd rather stick with the flat bevels. Already have a variable speed Bosch belt sander which doesn't get a lot of use on other stuff.

Sounds like the trick may be to get it set up properly - to organise some fixtures etc.

The Tormek is 10 years old but not much used. (i always did the planer thicknesser knives on it - but until the waterstones hand sharpened hand tools on diamond plates) It'd be nice to sell it, but I have most of the fixtures which can be adapted to other devices and no doubt no sooner than it would be gone some need or other would arise….

Thanks again David/guys, it's always great to be able to bounce stuff around. It's always tempting to think that El Dorado in whatever field is just around the corner, to question the status quo...

ian

Derek Cohen

10-23-2014, 12:14 PM

In the past I have ground A2 blades on a belt sander with 40-60 grit sandpaper.

http://www.inthewoodshop.com/WoodworkTechniques/TheSecretToCamberinBUPlaneBlades_html_m4429b60d.jp g

One can remove a lot of steel without danger of overheating it - just dunk in water regularly. The belt sander runs cooler than a dry grinder.

http://www.inthewoodshop.com/WoodworkTechniques/TheSecretToCamberinBUPlaneBlades_html_33aa4e76.jpg

I've done the same on a dry grinder. Again, slow work and use of water regularly. Here is a D2 jack blade I cambered using a 46 grit 3X wheel (I just hate the mess!) ...

http://www.inthewoodshop.com/WoodworkTechniques/GrindingNirvana_html_m7bc2497c.jpg

http://www.inthewoodshop.com/WoodworkTechniques/GrindingNirvana_html_7f1f6dda.jpg

Today the 8" 180 grit CBN wheel arrived. I set it up on the grinder. It replaced the 3X wheel. The guards were removed - the CBN wheel is solid steel and is not going to blow up! Using the Tormek BGM-100 set up I tested it on a 1" Stanley chisel. In no time it created a full hollow that resembled the Tormek hollow (smooth and even) but only took seconds to do. And no heat.

Regards from Perth

Derek

Chris Fournier

10-23-2014, 12:44 PM

The effort required to ruin an iron or chisel on a dry bench grinder would be monumental and there would be severely burnt digits involved. Sure you might monkey up a portion of blade, but having to grind back more than a 1/16" to 3/32" would be something.

The hollow bevel you get off of a bench grinder makes honing super fast and efficient and the right bevel angle for any given job prevents any undue damage to your tool. Given the advantage of registering a bevel on two contact points, the front and back of a hollow grind I'd be willing to bet that you use up less tool steel while acquiring sharp rather than having to deal with a flat bevel.

The bench grinder requires a workable tool rest, an appropriate wheel - grit and friabilty, and balancing. A good jig to hold your tool isn't a bad thing either. Once you have the machine sorted you simply need to take the time and develop the skills to use the tool. These forums are full of guys who haven't, won't, or can't effectively sharpen tools on a bench grinder. What is missing? In my opinion: patience and perseverance.

Set up your grinder while its turned off. Get the tool rest angle right and make sure that only the tiniest bit of steel is going to be removed in a pass. When you have run the tool over this setting until no more steel is removed simply give the tool rest a tap with your knuckle and go at it again until your hollow bevel is ready for honing. It takes time to develop the deft touch that allows you to walk up to this machine and get a good result with little fuss but it is by no means a black art. With time you will not even give the process a second thought.

The bench grinder is grat for metal working cutters as well as wood!

paul cottingham

10-23-2014, 12:48 PM

ian maybury

10-23-2014, 1:41 PM

Pardon my cutting across your question Paul. Thanks Derek, I've seen your stuff on setting up a belt sander for tool grinding - and confirmed it with a test… It was in large part what informed the decision to think in that direction.

:) Then I got sidetracked into building a grinder based on a disc sander which works just fine with a honing guide - I was attracted by the prospect of the nice flat disc. It sorted out some plane blades for me - but it definitely has quite a high heating tendency. Changing the self adhesive discs is a bit of a PIA also - although not bad if a heat gun is used to soften up the bond first. Notwithstanding what I said about setting up the belt sander another option might be to reduce the rpm on the disc - about 1/2 speed would place it with most tool grinding systems...

Jim Koepke

10-23-2014, 2:32 PM

It takes time to develop the deft touch that allows you to walk up to this machine and get a good result with little fuss but it is by no means a black art. With time you will not even give the process a second thought.

This may be the hardest part to understand and accept by those new to sharpening. The biggest impediment to learning to sharpen may be the fear of causing damage.

When my sharpening teeth were cut, a few of my blades did turn blue at the tip. The bright side of this is the metal is softer, it hones away easier. :eek:

To all the beginners, it is a process easier learned by experience than by reading or being told about it. What is even more amazing is no matter how sharp my skills can make an edge, I find there are still more things to discover about sharpening.

Most recently a thought struck me while using one of my pocket knives to shave a stick. This knife was given to me years ago and mostly sat in a drawer. It is kind of big for my everyday use and only has a single blade. Recently the knife was sharpened for the purpose of easily cutting rope. It was able to push through a rope and make a clean cut with little effort. When whittling the stick, it was a little difficult to get a good slice right handed, but it worked well left handed. There wasn't a bevel on one side of the blade and the bevel looked to have been made with a grinder on the other side. The bevel appeared to have been made by someone holding the handle of the knife to the right of the grinding wheel. This would be natural for someone who is right handed at the grinder. Slowly but surely I have been erasing the damage done in the past and making it work better whittling with either hand.

A few times at the Farmers Market a man named Dean has talked to me. He has done sharpening professionally. Hope to get together with him when we both have a little time this winter so he can share some of his knowledge.

jtk

Bruce Mack

10-23-2014, 2:48 PM

[QUOTE=Chris Fournier;2325123]

The bench grinder requires a workable tool rest, an appropriate wheel - grit and friabilty, and balancing. A good jig to hold your tool isn't a bad thing either. Once you have the machine sorted you simply need to take the time and develop the skills to use the tool. These forums are full of guys who haven't, won't, or can't effectively sharpen tools on a bench grinder. What is missing? In my opinion: patience and perseverance.

Set up your grinder while its turned off. Get the tool rest angle right and make sure that only the tiniest bit of steel is going to be removed in a pass. When you have run the tool over this setting until no more steel is removed simply give the tool rest a tap with your knuckle and go at it again until your hollow bevel is ready for honing. It takes time to develop the deft touch that allows you to walk up to this machine and get a good result with little fuss but it is by no means a black art. With time you will not even give the process a second thought.

Chris, I'm sure you're right and I like your explanation. My requirements have been met by my present set up so I don't think adding a grinder and tool rest etc. would improve my results, given my limited goals. Maybe in the future.

Chris Fournier

10-23-2014, 7:55 PM

So total grinder newbie question here, (I currently grind on stones or my Viel, the red sander/grinder from LV) when you grind on a wheel, how close to the edge do you get? Especially if you are grinding a new edge on a tool that has chipped, or is damaged?

I grind a brand new edge so effectively I grind over the edge! I realise that this may seem impossible to a person starting out but with the right touch it is easy as pie. As I mentioned, you won't wreck a tool with grinding mistakes, you'll simply use more steel than you really need to. When I say deft, I mean light and by light I maen feather light. The challenge is to understand how light is right.

HSS is a treat because you can blue it up as you please and it won't degrade the steel but our typical chisel and plane blades ain't HSS and blue is bad! Honestly if you are really watching what you are doing, straw, yellow, brown are all coming up before blue, purple and black!

David Weaver

10-23-2014, 8:27 PM

I'd agree with the edge comment, too - I grind mine pretty much off, but try to stop short of making a large wire edge. It doesn't present a burning problem, there's not much metal removal going on with a typical refresh grind.

Mike Holbrook

10-24-2014, 9:24 AM

It has taken me quite a while and a great deal of reading to figure out that my experience with the Tormek is not actually atypical. It is very slow, it wasn't something I was doing wrong. No amount of dressing the stone fixes the problem for very long. The other thing that I am a little surprised to learn, but should not be, is the belt grinder is potentially the fastest "conventional" route. Again this information corresponds to my personal experience. I have achieved my fastest results with the belt sander. I have found, much like David and others have explained concerning bench grinders and friable wheels, the heat can be managed if one pays close attention.

I am concerned with the dust created by a friable grinder wheel or belt though. I have had a number of bouts with allergic reactions in the last two years which give me reason to be paranoid of air borne metals & dust and skin contact with fine metal particles. The only real solution I see for me is the CBN wheel Derek mentions just receiving above. I understand that these wheels do not pollute the air nearly as much as friable grinders. I am also reading that these wheels can be wet down to further reduce and consolidate the refuse. Running one of those wheels on a Tormek seems like the "perfect" solution to me. Derek posted a link to a company in AU that apparently sells a CBN wheel that fits a Tormek. I am in contact with them trying to find out how crazy the shipping cost will be. I keep thinking that some company in the US should carry the same wheel but thus far I have not been able to find one.

Apparently Derek bought a 8" CBN wheel for his bench grinder instead of a 10" wheel for his Tormek. I am guessing his motivation was partly financial. I also think Derek may want to leave the regular wheel on his Tormek for bevel touch ups. I do not have a bench grinder at the moment. I am trying to figure out whether I am better off buying a new grinder and 6-8" CBN wheel or ordering the 10" wheel from AU. My guess is the two options will cost about the same if I don't go with an expensive grinder. I do not recall anyone commenting on brands/models of grinders which seems a little odd considering how much has been posted about people using grinders. From posted pictures it looks like just about everyone uses a different brand/model.

I have read about a CBN wheel with a rounded edge, which may be the reason Derek went with a grinder mountable wheel instead of a Tormek wheel? I am still researching, but I think the Tormek wheel in AU is the regular version of the wheel. I sharpen quite a few large green wood tools with curved, often hollow ground, blades so a curved grinding surface may be important to me. I also think the wheel speed of a Tormek is slower which may reduce the effectivness of a CBN wheel.

It is starting to look like a new grinder and CBN wheel are in my future. I know this is not the most financially conservative approach. Considering how much I have paid Dermatologists... and the amount of time and money I have spent researching and exploring options I am good spending the money if I am confident I have finally found a REAL solution to grinding bevels.

David Weaver

10-24-2014, 9:30 AM

(enabling people with little will power...)

Derek, you're an enabler. I just ordered an 80 grit wheel from a different seller. I'd assume that d-way tools is selling a wheel that someone else makes, but don't know for sure. The wheel I ordered looks a little different - the radius is similar, but it doesn't have a bushing (the bore hole is 1/2 inch on a 6 inch wheel).

The only reservation I have about CBN wheels is they warn you not to use them on softer metals (anyone who has stripped diamonds off of a nickel plate diamond hone will know why). I'm not sure how it will hold up with laminated irons, but it will make a good pairing with the pink wheel (which wears sort of fast..but not too bad I guess, and I have no cheap source for another one when mine wears out).

Derek Cohen

10-24-2014, 11:19 AM

David, you really do not need anyone to "enable" you to purchase sharpening equipment! :D

The 80 grit is indicated for heavy work. From what I could determine, the 180 grit is nearly as fast and provides a smoother finish. I am very impressed with this wheel so far, and well get the 80 grit for heavier work.

I got mine from D-way in the USA. I liked their presentation and reputation, and Dave Schweitzer answered all my emails promptly and thoroughly. You can find a few of his videos on Youtube. Plus the wheel they sell is 1 1/2" wide compared with the 1" wheel sold locally. I went for the radius edge as I thought it may be more useful, not only for lathe chisels (as they demonstrate), but also for entering and exiting on straight edges. Possibly for hollow blades as well.

David assured me that the CBN wheel will grind all hard steels. With regard laminated blades where there is soft steel, he mentioned that a grind on hard steel will remove any loading, if this occurs.

Installing the wheel is a simple affair. D-way (http://www.d-waytools.com/tools-diamond-grinding-wheels.html) sell a beautifully machined bushing that slipped over the 5/8" arbor on my half-speed grinder. This has a 1 h.p. motor, so is powerful enough to easily push this heavy wheel. It is so well balanced, however, that I imagine a less powerful machine just needs a manual spin (which I do anyway) to start it along.

I have not yet tuned it up - just slapped on the wheel and bolted back the tool rest. Still, I could not resist grinding a beater chisel.

http://i13.photobucket.com/albums/a262/Derek50/Sharpening/CBN%20Wheel/2_zpsab867457.jpg

http://i13.photobucket.com/albums/a262/Derek50/Sharpening/CBN%20Wheel/3_zps0a002adb.jpg

Grinding the hollow was quick, and there was minimal heat at the edge. This is the hollow on a 1" Stanley yellow handle chisel ..

http://i13.photobucket.com/albums/a262/Derek50/Sharpening/CBN%20Wheel/4_zps77008379.jpg

The microbevel after a Ultra Fine Spyderco is too small to see, however it proved its sharpness on Radiarta Pine end grain ..

http://i13.photobucket.com/albums/a262/Derek50/Sharpening/CBN%20Wheel/6_zps4dff5c6f.jpg

Regards from Perth

Derek

David Weaver

10-24-2014, 11:30 AM

I'm sure the 180 is plenty good for grinding bevels. I ordered the 80 grit because a seller offered me a cheap deal as I'd made an offer on a wheel on ebay but he sold it before responding to my offer.

I usually touch up turning tools with a diamond hone and sharpen them on a belt grinder, otherwise I'd have wanted a finer wheel too, to do turning tools.

It'll be interesting to see if it's cooler than the pink wheel (the pink wheel is fantastically cool for a wheel that doesn't release much grit).

Mike Holbrook

10-24-2014, 1:51 PM

I love this thread, very helpful! Woodworking=>Sharpening=>grinding bevels in my experience. After what seems like FOREVER I actually think I have the solution. Sure once we have a good bevel we can sharpen in a hurry, but first we have to have a good bevel, not getting around that as far as I can see.

So I called Dave and ordered a 1/4" radius 8" CBN wheel, and I don't even own a bench grinder, yet. Just so everyone is aware Dave does make a CBN wheel for the Tormek. His Blog/Web site does not reflect everything he has. He sells 10" wheels, which are not listed. He also says some people have used 8" wheels on Tormeks. Dave offered that the slower wheel speed would make the Tormek slower grinding even with a CBN wheel. Dave likes Jet 8" grinders and he has a Delta variable speed that he has used for 8 years. All Dave's wheels come with a 1" hole. He sells bushings to adapt any grinder to the 1" arbor.

Dave mentioned that Robo Hippy/Reed Graves a SMC member makes and sells a tool holding rig that works well with CBN wheels and grinders.

David Weaver

10-24-2014, 1:57 PM

I'd stick with a dry grinder, too. I don't know if he was explicitly saying any such thing, but low speed and high pressure is hard on grinding surfaces.

Good grinding frees you up to use anything to sharpen without worrying about how fast a particular stone cuts - that's a nice thing.

bridger berdel

10-24-2014, 2:49 PM

Daniel Rode

10-24-2014, 3:11 PM

That pretty much sums up why I started using a dry grinder. I can grind back a secondary bevel in a seconds or change the primary or radius in a couple minutes.

Good grinding frees you up to use anything to sharpen without worrying about how fast a particular stone cuts - that's a nice thing.

Kees Heiden

10-24-2014, 3:18 PM

I've read something some time ago about this, so I don't remember exactly. These sparks are something burning, a carbide or an oxide, don't know exactly. But they need ignition heat, and that comes from the rubbing of the steel against the wheel. They measured temperatures up to 600 degrees in a microlayer in the steel.

Sorry to be so vague. I really think it doesn't matter though. The overheated crystals are being removed when you hone the edge. And even when you accidentilly blue the steel a little bit, it isn't the end of that chisel. It is suboptimal, but it will be removed in the next sharpenings. There is no need to be anxious about grinding.

ian maybury

10-24-2014, 6:05 PM

Guess i can accept that minor heat effects are (probably - i'd love to see objective/microscopic proof of this) relatively easily honed off, but i'm not as relaxed as some seem to be about the risk of burning an edge. It isn't just a matter of skill/practice and good technique - not at least when the full range of grinding tasks is considered.

It's also a lot to do with matching the abrasive, surface speed, pressure and time between coolings to the actual job. i.e. it's necessary to have the right equipment setup (one that gives good control) as well as the right technique. Most woodworkers seem to do little except grind the honing bevel off on existing tools, and with a set up optimised for this it's not hard to get right - but it becomes a different ball game when the full range of possible jobs is considered.

Volume and area of metal to be removed are huge factors in choice of setup because pressure and speed are important variables so far as heating effect and metal removal rate are concerned. A set up that's fast enough to grind a new primary bevel on say a narrow chisel is going to be dog slow when it comes as I said a while ago to removing amounts of metal measured in mm grinding a new bevel on a 4mm thick + BU plane iron. The set up that does the plane iron in decent time will burn a narrow chisel in moments.

I'm as before influenced by having recently had to re-angle a lot of bevels and then sharpen the tools - everything from regrinding narrow chisels to re-angling the above plane irons. I have to say that I ended up frustrated as hell at not having a good one stop grinding solution to cover this full range.

I did my best. I have a Tormek and all the bits bought about 10 years ago, but while the water cooling is great it only grinds hollow and proved dog slow on the stock wheel on heavy jobs. (wonder if there is a coarse wheel available that significantly speeds it up?) I have a WorkSharp and it does a great job of producing flat bevels on smaller work off the top platform with a honing guide - but it's again dog slow on heavy jobs, eats expensive consumables like there is no tomorrow and isn't all that robust. Then I set up a disc sander based grinder like the WorkSharp for heavier jobs, and it can certainly shift lots of metal. Lots of care is needed though to avoid overheating once the bevel starts to thin a little - it runs at about double the surface speed of the WorkSharp, and it's too aggressive for light work. Plus it needs frequent abrasive changes.

So the one stop (flat bevel grinding) solution remains elusive, and doesn't seem to exist on the market. This thread has confirmed the thought that belt sanders have promise because because they run fairly cool, because there's a good range of abrasive types available, and because variable speed can easily be added. Low heat wheels on variable/low speed grinders ditto, but they grind hollow. Coarse waterstones are slow - hand techniques don't seem to cut it unless perhaps some of the Japanese lapping techniques can hack it? Then there's the CBN wheels Derek has just put up. They seem to run cool, they don't wear, they hopefully given the price last almost indefinitely, they are accurate, and they hopefully don't generate boron dust as it's very dangerous indeed from a health and safety point of view.

;) Wonder if there's a flat CBN grinding disc done that would fit a (maybe DIY) heavy duty variant of a WorkSharp equipped with variable speed?

David Weaver

10-24-2014, 6:18 PM

Steve Voigt

10-24-2014, 11:10 PM

you're way over thinking this

+1 to that. I have to admit I'm bemused by this whole thread. I tend to think that threads like this arise from thinking abstractly about sharpening, and reading internet threads about sharpening, rather than actually sharpening.

Guess i can accept that minor heat effects are (probably - i'd love to see objective/microscopic proof of this) relatively easily honed off, but i'm not as relaxed as some seem to be about the risk of burning an edge. It isn't just a matter of skill/practice and good technique - not at least when the full range of grinding tasks is considered.

No, that is simply not correct. It is a matter of "skill/practice and good technique." The order is reversed, though. Read up on the technique first, practice the technique, and once you've practiced enough, you will have acquired the skill. Just like any other woodworking skill. There's nothing magical about it.

Ian, I'm reading your posts and seeing you talk about Tormeks, Worksharps, CBN wheels, belt sanders, etc. All of these are expensive solutions to a non-problem. As has already been suggested by David, Kees, Dan, and others, not to mention folks like Joel Moskowitz and Larry Williams, the simplest solution is a dry grinder. Sell the Worksharp, Tormek, and all the other junk, buy a dry grinder, and you'll have enough $$ left over to buy some nice boards and a six pack.

David Weaver

10-24-2014, 11:42 PM

Ditto that, the real problem is that all of those other things were bought before a dry grinder. That was my problem, too (though I had a cheap dry grinder, early on before this was a topic on the forums, I had a 100 grit white wheel, which was not an insurmountable problem, but it wasn't a coarse wheel).

I've never once missed the tormek.

There is no "level of damage" on the edge of an iron or chisel, that kind of supposition has sold a lot of tormeks, but it has no practical place in a discussion with someone who has refreshed the grind on a couple of dozen irons (or fewer).

And bloggers and magazines have written about the "dangers of burning an edge" at length, which is hocum. Sure, you can do that if you do it wrong. You can also make miscuts on a dovetail if you don't use a router jig.

ian maybury

10-25-2014, 10:41 AM

One problem is that we really only find out the capability of the various methods when we try them - despite many being pushed as universal sharpening solutions.

The focus here is to sort out a good grinding solution, but we're maybe going to have to agree to differ on that one. The thread follows directly from my experience in the past couple of months in setting up a bunch of chisels and BU planes - using what I happened to have available.

It's not even a subtle issue - it's that a method that shifts steel fast enough to be efficient on a job like re-angling the bevel on a heavy plane blade is far too aggressive for safe (for the tool) back flattening and bevel grinding on a chisel. Or vice versa - that a WorkSharp (bought to put flat bevels on Japanese chisels, and doing that and flattening backs on them very nicely) simply hasn't got the clout for jobs like the heavy reworking of a plane blade described. As it happens I got by on the plane blades using the adapted disc sander described before, but it produces a hell of a lot of heat and forced dropping back to the WorkSharp to finish stuff once the bevel started to significantly thin.

Presuming that it occupies the magic minimal heat/high metal removal rate space (something I'm happy to accept) I'd happily use a coarse white wheel or even CBN on a dry grinder - but neither does the flat bevels I'd prefer to stick with, there doesn't seem to be a variety in either case that uses the flat side of the wheel (please say otherwise if this isn't the case), and anyway I don't have a tool grinder.

I've got this far, and can continue with what I have since it's going to be mostly about relatively light duty re-grinding of bevels to eliminate the honing bevel from here on - but I'm left looking at what is an unsatisfactory mish mash of solutions. There has to be scope for a one size fits all flat grinding solution. e.g. a belt grinder with variable speed that at one end of the scale cuts at about the rate of the WorkSharp, but that at the other can shift a lot more metal and not cost an arm and a leg for consumables.

There's no fundamental issue in that there's something that I need to sharpen that I can't - but my instincts very much suggest that there has to be a single/one stop/much more elegant solution possible that would allow the offloading of all of the half and high risk solutions….

Derek Cohen

10-25-2014, 10:59 AM

Why did I go down the Tormek wet grinder route, then (several years later) purchase a CBN wheel for a dry grinder?

First off, I am not trying to send a message that says "this is the best and this is what everyone should also get". Everyone must do what they feel suits them best.

All I seek from a sharpening system is one that is efficient and leads to sharp edges with the minimum of fuss. However, what works for me does not necessarily work for others. Follow my lead at your own risk.

Is it cost effective? Does it cost too much? Frankly, that is of little importance to me. I can afford what I have purchased. It is not up to others to decide what I can afford. Decide for yourself what you can afford. There are lots of ways to spend money on sharpening systems, some of them in my opinion are a waste of time and money, and some of mine are no doubt for others a waste of time and money! :)

On average I can grind a blade and hone it in just a few minutes. Resharpening takes under one minute. CBN wheel for grinding - to the edge of the blade. It is warmer than a Tormek, but much much faster. The final hollow is slightly deeper. It will last slightly longer. It is important that the edge is smooth and the hollow grind is straight. This means much less work to do in terms of preparing the edge with a coarse stone.

I freehand on the hollow and, after the CBN, shape in a camber on a broken-in Eze-lap Fine grit. I've had this stone over 10 years now. Magic! This is followed by a Medium Spyderco, which raises a very fine microbevel in about 8 strokes. On a PM-Vll blade it is so small that one must look carefully to see it. Five strokes on a Ultra Fine Spyderco, and I could call it done. A few strokes on either Veritas green compound on planed hardwood or the 0.5 micron diamond mesh, and the blade is very, very sharp.

No water. No mess. I can focus on the important part of woodworking - working the wood.

The irony is that the CBN wheel creates a perfect hollow and the Spydercos remove so little steel that the hollow looks like it will last a long time ... and grinding will be done so infrequently! :)

Here are images of the edges created on a 1" PM-Vll chisel blade. Firstly off the 180 grit CBN wheel ...

http://i13.photobucket.com/albums/a262/Derek50/Sharpening/CBN%20Wheel/1-CBNa_zps7ef5a096.jpg

Secondly, the Medium Spyderco ...

http://i13.photobucket.com/albums/a262/Derek50/Sharpening/CBN%20Wheel/2-Medium-Spydercoa_zps439caf8f.jpg

Then the Ultra Fine Spyderco ...

http://i13.photobucket.com/albums/a262/Derek50/Sharpening/CBN%20Wheel/3-Ultra-Fine-Spydercoa_zpsee6e86ce.jpg

Finally, a few strokes on a 0.5 diamond mesh to add a final polish and ensure the wire edge is gone. And demonstrating that edge on soft Radiata Pine ...

http://i13.photobucket.com/albums/a262/Derek50/Sharpening/CBN%20Wheel/6-Paringa_zps031ff8b9.jpg

The stones: Medium, Ultra Fine Spydercos, Diamond mesh (on perspex on hardwood), and Fine Eze-lap.

http://i13.photobucket.com/albums/a262/Derek50/Sharpening/CBN%20Wheel/7-stonesa_zps37617ac7.jpg

Regards from Perth

Derek

Mel Fulks

10-25-2014, 11:08 AM

Mike Holbrook

10-25-2014, 11:13 AM

My problem with a grinder has been concern over the refuse they throw in the air more than the heat issue. My allergy issues create a level of caution beyond what most people would be concerned with. I picked up a Delta 8", variable speed grinder yesterday when I was at Lowes. The low speed is 2000 instead of the more typical 1750 or 1800 low speed on more expensive grinders. The top speed is 3400. I am not sure I need the speed adjustment anyway but it might come in handy. Any reason this specific grinder might not handle typical grinding chores?

I have a 8" CBN wheel with rounded edges, hopefully shipped. I am wondering what to do with the other side of the grinder. I would like something that would provide more grinding help, maybe Dave's 80 grit CBN wheel. I don't plan to order another expensive CBN wheel though until I try out the 180 grit I ordered. I was also wondering about a leather or felt wheel for buffing. The Tormek has a leather wheel I can use but it will remain in another room, the rotation speed is quite slow and I might sell it or trade it off. I wonder if a buffing wheel of some type moving between 2000 and 3400 rpm might be useful? I don't think most buffing wheels throw off much in the way or airborne refuse. I plan to do the major part of my touch up sharpening on my Spyderco stones, but a little buffing might help too? I am also considering a stone/ceramic wheel if I can find something that does not toss up too much dust. I do have dust masks, although I don't particularly like wearing one. They tend to fog my glasses among other things.

Derek Cohen

10-25-2014, 11:22 AM

Have not used the pm 11 but have been reading the good reveiws. I'm surprised at how ragged the newly ground edge is
in that photo. Was it ground without moving the chisel side to side, or is that just the nature of that steel?

Hi Mel

I thought that someone would comment on that. It is not typically ragged like that off the Tormek. It may be that the CBN wheel is new and still wearing in. It may also be (more likely) that I ground a little further than I would usually as the wheel on the dry grinder is set up fractionally off the line of the Tormek, and it was necessary to grind fractionally further to square the edge.

The final edge was smooth.

Regards from Perth

Derek

Steve Voigt

10-25-2014, 12:00 PM

It's not even a subtle issue - it's that a method that shifts steel fast enough to be efficient on a job like re-angling the bevel on a heavy plane blade is far too aggressive for safe (for the tool) back flattening and bevel grinding on a chisel.

I hate to keep saying this, but the above (at least the part about bevels) is simply not true and just reflects a lack of practical experience with dry grinders. I have used a cheap 6" grinder to grind 1/8" chisels, and I have used it to put a 20° skew on a 2 1/2" plane iron and then regrind a whole new primary. The dry grinder is perfectly fine for both tasks--the difference is simply a matter of touch. Use a delicate touch for small things, be more aggressive with larger objects. That's it, that's all there is to it, other than practice.

In my old machine shop, where time was money, we used dry grinders for virtually all rough sharpening tasks. The only exception was really large lathe drills. If I needed to sharpen a 3" diameter drill, I'd do it freehand on a belt or disc sander. But that is a scale of metal removal that the hobbyist woodworker is unlikely to encounter.

For flattening backs, the dry grinder is obviously no help. But that is a completely different task from grinding a bevel, and it seems rather quixotic to expect one device to be able to do all things equally well. A tablesaw is great for all sorts of things, but I don't expect it to cut curves.

bridger berdel

10-25-2014, 1:09 PM

For me that optimal setup is a dry grinder, 2 stones and a strop. It does require a minimum skill level with the grinder, so there is an investment of time and a few practice pieces, but the payback in time saved down the road is pretty good.

Mike Holbrook

10-25-2014, 1:21 PM

Derek, thanks for the additional pictures and report. It sounds/looks like grinding nirvana to me.

From what I understood from Dave concerning the longevity of his CBN wheels, I suspect this solution will turn out to be very cost effective over time as well. Maybe, including the spyderco ceramics and a couple diamond plates, we have a complete system that will be very fast and likely outlast us. Will be nice to get back to working wood with sharp tools vs worrying with sharpening issues so much of the time.

David Weaver

10-25-2014, 1:54 PM

Have not used the pm 11 but have been reading the good reveiws. I'm surprised at how ragged the newly ground edge is
in that photo. Was it ground without moving the chisel side to side, or is that just the nature of that steel?

V11 holds on to its wire edge pretty stiffly, so you're not going to get a clean toothy edge like you'd get from hard water hardening steel. If you thin it, it comes off fine, though, especially if you strop or use a really fine stone (as in the edge is still smooth).

David Weaver

10-25-2014, 1:58 PM

Bruce Mack

10-25-2014, 2:49 PM

David, could you talk about a basic set-up, recommending grinder size and make(s), wheels, tool rests and/or jigs, truing tools? I'm not sure I want or need to do this but do want to think about it. Thanks.

David Weaver

10-25-2014, 3:26 PM

* Low speed 8" grinder or high speed 6" grinder. The make isn't that important, an import grinder is fine, just don't use the cheapest looking thing you can find because it'll have trash rests and a very low amp motor. $100 will get something 6" and import that's pretty good. i don't know what the price of the 8" slow speeds are, but they probably have wheels for turners on them instead of hand tol users, anyway.
* 46 grit wheels of moderate softness. Best I've seen so far are pink surface grinder wheels, but they are not cheap. it's nice to have one on one side and a harder wheel on the other for tool making or heavy grinding.
* dresser can be anything - I use the cheap T grinder that you can find on amazon. It strips the wheel of glazed abrasive fast
* need two piece rests. I use stock rests, nothing else. Everything else, actually, is a nuisance to me. When I had a cheap import grinder (I have a baldor now), it had two piece aluminum rests with detents. I ground the detents off so that it wouldn't settle in at specific angles and it was fine with the aluminum stock rests. I didn't really need to get a baldor, but I guess I was into treating myself, and at the time, baldors weren't that expensive (mine was about $270 or something as the 6" grinder with cast guards and cast two-piece rests. I think they want the moon for them now).

That's pretty much it. Keep the rests free of rust or anything sticky and keep the wheels dressed fresh. The remainder of the equation is just touch, and not that much of it is required. That and experience (and not that much of that is required, either.

Bruce Mack

10-25-2014, 4:11 PM

Thanks David. I think I'll do it. Just had apparently successful back surgery so will wait until I get clearance for lifting, probably 3-6 months.

ian maybury

10-25-2014, 5:33 PM

Reinis Kanders

10-25-2014, 7:17 PM

I use worksharp with foot pedal and 100 grit diamond plate and it works pretty well for flattening backs of the blades, but I only flatten first inch or so. Seems to work, same for chisels, but there I flatten a bit more than inch. Everyhing seems to be sharp enough. I mostly work with soft HD pine, fir, cedar or soft maple because that is all I have around here within a 45 min drive.
Diamond plate also dissipates heat better and I vacuum off swarf from it while flattening.

Chris Parks

10-25-2014, 8:30 PM

I have a question for Derek, is the linisher you are using high or low speed?

David Weaver

10-25-2014, 9:01 PM

Think there's cross purposes involved here David, and it'd be a pity to end up arguing. I can assure you that a WorkSharp can do an excellent job of flattening chisel backs when correctly used. Anything that gives good control, removes material fast enough to be reasonable (multiples of the rate of removal by a 120grit waterstone), puts in minimum heat and creates a surface flat enough to subsequently clean up all over in a minute or two on a 1,000 grit waterstone can't be doing a bad job. It requires a fair degree of finesse in use, but if you too found yourself with little option but to work through a full set of chisels (bought some years previously, left untouched as a result of illness/other priorities and past being returned) with unexpectedly badly humped backs one after another you would likely find yourself quickly looking for a power assisted back flattening method too...

You're a better man than me though if you can get a WorkSharp to remove the large amounts of metal needed to reset the bevel angle on a thick BU plane iron within a reasonable period of time, and without requiring a second mortgage for consumables. Especially at UK £ to dollar prices. I wouldn't think of trying to use it to flatten the back of a plane iron unless it was very close already, it's just not big enough. Luckily the issue hasn't arisen given the excellent flatness and surface finish of Lee Valley BU plane blade backs.

For sure it's also possible to correctly grind a small tool on a high speed high heat inducing grinder - it's only a matter of reducing the pressure and contact time enough, and of achieving accurate alignment from first touch. It's clearly not the preferred option though, because it all becomes a very touchy operation - you wouldn't be using pink low heat low heat stones on your own grinder if it was.

It seems clear that what you describe is a proven high speed/low heat solution, but it's hollow grind.

You may well be correct that a hollow bevel is OK on japanese chisels (and it's clearly very convenient), but there's an awful lot of people out there that would (rightly or wrongly) beg to argue that it's not a good idea. I don't have a firm view on the matter. The decision to sharpen my set of chisels single bevel was entirely pragmatic. i.e. it was made on the basis that (as a person new to Japanese chisels) I wasn't if I could help it going to risk finding out the hard way that there is good reason for the caution about hollow grinding them.

I'm not keen on using all sorts of different bits of equipment if I can avoid it, hence this thread in the hope of flushing out some one stop flat bevel grinding solutions (a variable speed belt sounding very promising because it should be able to handle the more delicate tasks done by the WorkSharp, and also the faster metal removal with low heat build up that's useful for working heavy blades) - but don't mistake my floating a question based on a line of thought for dogmatism or some sort of fascination.

It may or may not prove a good option in practice, but it seems worth a look before discarding the possibility. One option should it prove impractical would be to trial a few chisels with a hollow grind and see how that goes...

I'm not defending the worksharp, I think it was popular for reasons that I don't know, and for a while it was really popular. I'm describing a dry grinder as the only power sharpening tool anyone needs to have in a shop to work quickly and without damaged tools.

A couple of other items:
* Japanese tools shouldn't need a grinder at all, they are designed to be honed on the full flat bevel with very soft metal backing the iron. I haven't had to grind a tool that's in use in several years (in terms of japanese tools) and have only ground an inexpensive jack plane and some used or cheap irons that have showed up far out of shape. The plane that I have set up like a jack does get ground with a dry grinder from time to time with no ill effect.
* backs on all tools should be lapped by hand - it needs to be done only once, and it's best if it's finished on whatever will be used to polish the wear off of the back of an iron. If someone uses a worksharp from A to Z every time they hone, then it may be appropriate for flattening backs because there will be no stone for it to disagree with.

The case that there is no damage to blades off of a dry grinder with an experienced user is not dogmatism. The opposite is nearly true. For years we heard about dry grinders burning edges and hollow grinds being weak, and things didn't change until there was a magazine article about using a dry grinder. As far as the hollow goes, there still seems to be people believing that there may be some weakness from a hollow off of a 6" in diameter wheel, and that's not the case. I challenged the entire forum over a period of years to show damage on any edge that was suspected to be due to a hollow grind on any common grinder in use and there has never been any.

I used to trouble over the same thing and try to set my edges so that the lowest tangent off of the hollow would be as great as what I would've had for a flat bevel, but all of that stuff is such a waste of time.

Derek Cohen

10-25-2014, 9:13 PM

Hi Chris, by linisher I assume you mean the belt sander. It is such a basic machine that would not give it a more prestigious name! :)

http://images.machineryhouse.com.au/products/L107/700/Main.jpg

The first machine I purchased was a cheap sander for wood and intended solely as a grinder for blades. I could not justify spending more on a linisher for metal. It developed electrical problems and the store took it back and I spent a little for a better model. This has 1 hp and runs at 1400 rpm.

Again, it was erely intended to grind metal. The graphite plattern was removed to work on the flat cast iron. The belts used ranged from 40 grit upward. It worked very well as a grinder: relatively cool - much more so than a dry grinder wheel - and the jig I built was accurate enough for repeating a bevel angle. I still have it, but now it is mainly used for the disk sander. I stopped using it when I started freehanding blades more regularly and discovered that a hollow grind was easier to use in this regard.

Regards from Perth

Derek

Chris Fournier

10-25-2014, 10:36 PM

Those sparks indicate heat being REMOVED from the blade. It's the heat that remains that is the issue

Someone has actually learned about sharpening, but likely not from a woodworking forum! Sparks can fly and you can still touch the cutting surface when all is right.

Get the right bond, frialbility, and 46 to 60 grit will serve you well forever on WWg tools. No need to ramp things up to anything fancier unless you are sharpening HSS all the time. Even then CBN is not a must, nor is diamond. I have CBN in my machine shop for use on carbide, all HSS for th elathe and mill gets the AO cup.

Folks over complicate and invest in sharpening processes all the time. KISS and trust the time honoured methods, you'll be just fine and missing out on nothing from a practical standpoint. Bragging rights? You may be second in line.

Chris Fournier

10-26-2014, 12:03 AM

Ian, you're way over thinking this, there is no point where you'll have any practical problem with a dry grinder unless all get and swarf must be captured.

You don't need to hone off any appreciable amount with the stones, either. I don't, and I grind right to the edge and did when I used a cheap gray wheel. It just needs to be coarse and dressed. I don't even keep water at my grinder.

I have been waiting for this for some time David! The pot calling the kettle black. Over thinking is stock in trade around here if you know what I mean, and "practical problem" had me bent over gasping for breath between peals of laughter. Thank you for the comic relief, contextual of course. Nonetheless you are absolutely correct, there is "overthinking" afoot, it thrills me that you recognize this!

David Weaver

10-26-2014, 10:27 AM

Reggie Jackson strikes again!!!..."pselling" error and all.

Chris Fournier

10-26-2014, 12:02 PM

Reggie Jackson strikes again!!!..."pselling" error and all.

It was a pie cooling on the window sill David, too good to pass up. "Reggie Jackson" was a nice touch! I had to Wiki him to get the full meaning.

All future pies will stay on the sill. Chris.

Noah Wagener

10-26-2014, 6:40 PM

[QUOTE=ian maybury;2324887

It's early days for me on the white steel chisels David, so it's not a case of having a firm view. A coarse stone that will hand regrind bevels fairly quickly sounds like a good test. Perhaps it's because so far i've mostly been forming/re-angling bevels, but even the Shapton 120 seems a little slow though. Wonder if a coarse Crystolon would do any better?[/QUOTE]

I happened across an Australian forum where Stu Tierney wrote that a Sigma 120 is about as fast as a powered grinder. I do not know if your Shapton is a glass stone but he also wrote that that stone (the 120) is rubbish. i would think Crystolon stones need to be very friable as they are silicon carbide. The sigma apparently does not wear yet maintains speed.

Noah Wagener

10-26-2014, 6:47 PM

ian maybury

10-26-2014, 8:11 PM

This is to respond to several posts at once. This isn't meant in a combative sense, but it's all very well to talk about over thinking, and once a person has a simple method that works for their purposes it's got to be very temping to fly that particular kite. The fact is though that almost everybody here talks of working through potentially quite a long evolution of methods to get to what now is 'obvious', but which in retrospect wasn't obvious at all. Not only that - if it's so obviously the 'right' way to do a job, why is it that so many don't necessarily agree? (there's lots of reasons many of which don't hold water and some which do, but the end result is a cacophony of competing recommendations)

:) I guess it'd certainly help a lot if there were 'certified' solutions out there. It equally though ought to be possible to table problems and/or possible development directions on a forum.

One complicating factor in all of this is not everybody has the same set of requirements - because their situation or tool is different enough to matter. I keep on banging the drum on this, but grinding a new bevel angle on a thick BU plane iron is a very different ball game to just grinding off the honing bevel on a relatively much thinner BD iron for example.

The other issue is prior investment. So a soft bond wheel on a low speed grinder is the greatest? Wonderful, but what if you have already invested to head down a different road which has some strengths too. Do you change tack buy a new grinder and soft wheels, only for example to find that as a method this contains shortcomings too? That doesn't mean that it's not the right thing to do, but for sure you're going to seek ways to get your current investment working better before dumping it...

That's been my situation, and I'd so far rather stick with flat bevels. Be that as it may it's become clear that the classic bench grinder is a highly cost effective solution. Minimum parts count, simple fixtures, minimum cost, good access to the wheels for changing angles etc. Add variable/low speed and low heat wheels and it takes another step forward. A belt type grinder has some potential advantages - but it's for example instantly a more complex and more expensive piece of kit - a fact reflected in the relatively higher cost of decent quality linishers etc. Plus it seems that there's little available with the variable speed etc that would be ideal.

That sander Derek is sold in the UK under the Clarke (a moderate cost eastern) brand. This guy might be a prospect too, but it's going to be a bit more expensive, and would ideally need variable speed: http://www.vansantdistributing.com/Multitool_4x36_Belt_Grinder_Attachment_p/mt364.htm Quick belt changes between a wide variety of grits is an advantage.

Thanks for the input on the 120 waterstones Noah. I actually have a 120 grit Shapton professional, but have been quite disappointed by it. I'm even suspicious that it may be a bad example - it had three relatively significantly harder granules at one end for quite a long time. They have by now ground away, but it begs the question of whether or not it's a good example of the type. It cuts at nothing remotely near the speed of 80 grit Al oxide paper on a 1,420 rpm disc sander (and is multiples slower than the WorkSharp too on the same grit) - but the sander is running at about 3,500 ft/min or about x4 the surface speed of a WorkSharp which must go a long way to explaining both the high metal removal rate and the heating the former produces.

David Weaver

10-26-2014, 8:27 PM

This is to respond to several posts at once. This isn't meant in a combative sense, but it's all very well to talk about over thinking, and once a person has a simple method that works for their purposes it's got to be very temping to fly that particular kite. The fact is though that almost everybody here talks of working through potentially quite a long evolution of methods to get to what now is 'obvious', but which in retrospect wasn't obvious at all.

Many of us, myself included, don't like to settle on someone else's knowledge all the time. And the trouble with that is it costs us a great deal of expense to fiddle around with everything. I was lucky to get a tormek used, but I bought some accessories for it. I sent them to george. I'm down $500 on that. Waste.

I then bought a version of the viel grinder and blew up the motor on it. I still have the grinder parts in my shelving in the garage, I've got to find someone who has a motor and wants a grinder, and who will pay enough to make it worth putting in a box (which isn't much).

And then I had either an 80 or 100 grit wheel on a ryobi grinder, white wheel - that's what rockler had in stock here. Bad choice. Maybe good for HSS, bad for other stuff.

I tried using a belt sander of the style derek shows, but a bit smaller. It wasn't as precise as a belt grinder, and I replaced the viel with a small kalamazoo grinder (nice machine for the price).

And before that, I went back to the gray wheel on my ryobi grinder and used the grader every time I ground something (the gray wheel that came with it was 46 grit). That was the end of it. Even the gray wheel didn't burn things that easily, the grit size is the key. And I splurged and bought a baldor.

Most of us want to do this kind of stuff, fiddle. I have four wheels for my baldor grinder. Two brown gemini wheels, a white H hardness wheel and a pink surface grinder wheel, and now a fifth - the CBN wheel coming.

I've done enough tinkering that if george tells me something now, I'm willing to believe it. You can go and spend all the money you want, and you can discount what we have concluded (many of us who have thought the same thoughts you're thinking before - none of us is as unique or cunning as we like to think we are, someone else has thought the same things, and recently.). Just don't be surprised if you either:
* don't conclude the same things we have, and find yourself never quite satisfied with the method you choose
* do conclude the same thing and find yourself quite satisfied and realize this was all a waste of time, and has stunted you from thinking about things that will really matter in the shop, most notably training your eye

David Weaver

10-26-2014, 8:35 PM

I wish i would have read this thread a few days ago. I bought an 80 grit grade k stone and it is not much better than the gray wheel. Despite the claims that i will never blue a tool; on thin bevels it gets hot in seconds and the grinder is only foot powered. It is a neat feeling how the hollow ground bevel registers on the stone though.

You can obviously avoid bluing things with a wheel that fine, but it takes willpower to keep the touch light, especially when you have that last little corner that's left with more on than you want, etc.

A 46 grit wheel will solve your issues.

80 and 100 grit white wheels create a lot of heat, even when just resetting a bevel.

David Weaver

10-26-2014, 8:53 PM

I happened across an Australian forum where Stu Tierney wrote that a Sigma 120 is about as fast as a powered grinder. I do not know if your Shapton is a glass stone but he also wrote that that stone (the 120) is rubbish. i would think Crystolon stones need to be very friable as they are silicon carbide. The sigma apparently does not wear yet maintains speed.

Crystolon stones are a great bevel grinding stones. I know stu's stones had loading problems initially, but that's probably because they're harder than crystolon stones, and also because they're not using the right fluid to carry away coarse swarf. Coarse swarf needs a thicker fluid.

A coarse crystolon is probably the best bevel work stone I know of, though I haven't used stu's sigma stone (which is some type of silicon carbide like a crystolon stone). I'd personally rather have a medium crystolon, though, and use it a little bit more often.

I don't know of any stone that works as well as a grinder when the grinder is properly set up. I'd imagine it's less than 30 seconds of actual grind time for me to remove 4 or 5 honings worth of wear and stop right at the edge.

Derek Cohen

10-26-2014, 9:27 PM

it's all very well to talk about over thinking, and once a person has a simple method that works for their purposes it's got to be very temping to fly that particular kite. The fact is though that almost everybody here talks of working through potentially quite a long evolution of methods to get to what now is 'obvious', but which in retrospect wasn't obvious at all.

Hi Ian

That is a fair comment. Sharpening is one of those skills that everyone needs and most can do well enough to get by .. and therefore there are lots of opinions .. probably more posts on sharpening than anything else. Not all of it is helpful to someone that has moved past the beginner stage and has begun recognising their own special needs, and questioning the advice given. There are too many variations possible to prevent this being anything but a minefield for the intermediate sharpener. One of the other issues that goes with this is that our direction in woodworking can change as well, and with this our methods.Some of us here have been around long enough to know what we want, and have spend time (and money) learning what works for us. At times we forget that we have differences of need and personality, and advice can sound quite black-and-white.

One complicating factor in all of this is not everybody has the same set of requirements - because their situation or tool is different enough to matter. I keep on banging the drum on this, but grinding a new bevel angle on a thick BU plane iron is a very different ball game to just grinding off the honing bevel on a relatively much thinner BD iron for example.

I assume that you are using 25 degree primary bevels and adding a secondary micro bevel on your BU irons? If not, read this article I wrote some years ago: http://www.inthewoodshop.com/WoodworkTechniques/TheSecretToCamberinBUPlaneBlades.html

Whether you prefer a belt sander or a wheel grinder to create a primary bevel here, the aim is simply to create that primary bevel, and not to "sharpen" the blade, er se. I tried that and gave it up many years ago. I still have belts for the belt sander that will take the edge to about 10000 grit! It is just too much work and too slow. A secondary microbevel is much quicker. This is best done with a honing guide (not freehand - save that for BD planes and chisels) to achieve the angles needed. This said, the grit needed for a belt/wheel is best as coarse as possible to keep down the heat.

This is the direction I took.

Regards from Perth

Derek

Steve Voigt

10-26-2014, 11:28 PM

I wish i would have read this thread a few days ago. I bought an 80 grit grade k stone and it is not much better than the gray wheel. Despite the claims that i will never blue a tool; on thin bevels it gets hot in seconds and the grinder is only foot powered. It is a neat feeling how the hollow ground bevel registers on the stone though.

Hey Noah,
This is a little OT, but…I'd love to see some pics of your pedal-powered grinder. That sounds really cool. Did you build it yourself, or is it a vintage grinder?

ian maybury

10-27-2014, 11:52 AM

Think I should have said as well that another factor in the scenario is misleading marketing by those selling the sharpening hardware. That becomes a major issue when you live a long distance from stockists, and it's not possible to inspect stuff before purchasing.

Have to say that your circuitous path to Nirvana makes me feel OK David. :) Truth be told i think we're screwed once we stop taking responsibility for ourselves/listening to our own insight (that doesn't mean ignoring external input - but there has to be a filter) - so maybe it's inevitable that we each have a path to follow. There's a Buddhist saying on what is perhaps the broader reality of stuff like this that approximates to: 'the cows all take different paths to the barn, but they get there just the same'.

There's no question of trying to sharpen off a grinder Derek - i've been getting great edges off Shapton waterstones. The WorkSharp was bought solely to grind flat bevels and backs. Trouble is its turned out (inevitable i suppose given its DIY/price point led and pretty minimalist spec) to deliver relatively low rates of metal removal (pretty much inevitable on single speed given that it has to handle chisels too) and to eat (over here) very expensive consumables. On the positive side it does a great job when the area/thickness of metal to be removed is minimal - but no more. Plus I'm a bit wary about longevity. The Tormek is a legacy from years and years ago bought primarily to sharpen power planer knives. It proved dog slow on the stock wheel for that, the jig wasn't great and (so far) not wanting hollow ground bevels I've avoided using it for hand tools. It does lots of odd jobs though.

Your site actually switched me on to using 25 deg BU blades for everything, and honing camber and micro bevels as required by the job. Trouble is that previously (some years ago) I unthinkingly bought a few BU planes and some spare blades in various bevel angles from Lee Valley, and wasn't going to throw them out. (it's not cost effective to bring over small lots of stuff, and it's much more expensive here) I got them re-angled very nicely using the previously described 80 grit disc sander - but it's a very touchy job given how much heat it produces at its high surface speed and I'd prefer something a little more forgiving of a minor slip.

Hence as before the continuing search for a one stop flat bevel grinding solution - which is proving rather more difficult than expected given some additional requirements.

It's very helpful to be able to grind using a honing guide to set the angle as it means the Japanese chisels subsequently sharpen single bevel very easily on the waterstones. It means though that the any flat grinding solution with this requirement in mind must if lots of remedial waterstone work is to be avoided (a) have a platform that can be accurately adjusted level and absolutely flush with the working surface of the disc/belt, (b) grind accurately flat surfaces (bevels and backs - and belt sanders don't seem necessarily to do this), (c ) be capable of running at low WorkSharp like surface speeds/metal removal and heating rates for small area/finer work (e.g. chisels etc), and (d) be capable of being adjusted to cut much faster for the occasional heavy job that comes up like the re-angling of the plane blades. (which probably suggests a requirement for variable speed)

David and others will by now be having fits, but right now i'm thinking seriously of sticking a small VFD on the disc sander which is already set up with a work platform. It's advantage is a dead flat aluminium backed surface, the disadvantage is that changing the self adhesive sanding discs requires use of a heat gun and is a bit of a job compared to throwing a new belt on a belt sander...

David Weaver

10-27-2014, 11:58 AM

You'd be far ahead with a belt grinder with a VFD and hard and soft platens (if that's the route you want to go). Sooner or later you'll get a catch on a disc sander with an aluminum backing (most of which do have some flutter) and when you do, catastrophic things can happen - like irons bouncing across the shop.

A disc sander is a widely available but not very good option. You have to create some kind of fixture that will keep your iron from grinding out of square, too. (well, you don't, you can just use a fixture that gets the iron close and then allows you to use touch to correct small squareness issues.

ian maybury

10-27-2014, 12:23 PM

That seems to be about the choice David - with biting the bullet on hollow ground bevels and reverting to a bench grinder based solution as the other feasible route. Perhaps i've been lucky, but the sanding disc in this case (an old 90s Record) is dead flat.

The Lee Valley mk2 honing guide with the full width cylindrical roller does a good job of holding a plane blade square - although it needed some dialling in first (by filing the mounting surface on the roller assembly bracket) as the roller wasn't as delivered quite in the same plane as the blade clamp.

I did one blade using the cambered roller in the guide, and relying on my eye-balling the squareness. It worked, but it's very touchy. Even a small amount of extra pressure applied to one or other side of the blade will cause it to tilt out of square as a result of extra metal being ground off from that side. Worse still - do it on the other side as well and you would end up with a humped bevel which would greatly increase the amount of honing subsequently requiring to be removed on the waterstones to create a full width micro bevel….

David Weaver

10-27-2014, 12:34 PM

These are things you would completely avoid with a hollow grind. there are times I've noticed irons or chisels getting slightly out of square, but never close to outside of the adjustability of a plane or outside the envelope of easy use with a chisel.

When you notice something a tiny bit out of square with a hollow grind, you just favor that side of the tool when sharpening for a grind or two and it's out.

I'm going to send subliminal messages in type and say I'll see you back here in this thread next year when you have glowing thoughts about a dry grinder.

(my CBN wheel arrives today, I might make a random comment about it if I get a chance to use it tonight. I'm curious as to whether or not it may actually be cooler than a coarse pink wheel).

ian maybury

10-27-2014, 1:16 PM

It's very possible David. (the glowing comments)

The CBN looks very interesting. The big question for me presuming it does the business is the life - it's expensive enough at around €180 per wheel.

If it gave a long life it'd be dead interesting for doing flat bevels if there was a fully coated disc available - even a disc that fitted the WorkSharp.

It's possible as well to grind a flat bevel off a wheel (whether CBN or something else) by feeding the item in the direction of the plane of the disc too...

dan sherman

10-27-2014, 2:47 PM

I'll add my two cents.

A six or eight inch dry grinder with an appropriate wheel is probably the cheapest powered way of quickly removing material from the edge of a tool. In my opinion the number one thing people screw up, is getting the appropriate wheel. Usually then end up with a high grit hard wheel that's designed more for touching up hss turning tools than sharpening a tool steel plane or chisel.

If you turn to the abrasive section of just about any industrial wholesalers catalog, you will find a chart like this that explains how to decipher a girding wheels information code.
299090

Another good source of information is the actual wheels manufacture. Take a look at what Norton recommends.
http://www.nortonindustrial.com/uploadedfiles/sgindnortonabrasives/documents/catalog_pdfs/nortoncatalog-toolroomwheels-technicalandcrossreferences.pdf

For reference this is what I have on my 6" grinder. It does an excellent job at removing stock quickly and not producing a lot of heat.
http://www.use-enco.com/CGI/INSRIT?PARTPG=INSRAR2&PMAKA=890-8909&PMPXNO=3507702

For flattening the back of a plane or chisel, a work sharp is probably the cheapest powered option. The best option is probably a variable speed 2x72 belt grinder with a glass planten.

Bruce Mack

10-27-2014, 2:51 PM

I think, therefore I dither. Confession: at home sharpening aids include Worksharp (acquired at low cost), King stones, Naniwa stone, Shapton stones, Veritas plates with oil soluble diamond paste, granite plate for scary sharp, Diasharp coarse for flattening Shaptons, Spyderco stones (given to friend), Eze Lap coarse and fine on order, Eclipse, Kell and 2 Veritas jigs, crystalon stone, steel plate and silicon grit for flattening same. Haven't yet gotten a grinding wheel or Lap Sharp. Are my blades sharp? Yes. Thing is I like to mess around in the shop, sometimes more than working wood. In my other life I was disciplined and productive. Here I'm a happy advocate of Brownian movement. Sorry to hiccup the thread.

Noah Wagener

10-27-2014, 4:57 PM

A coarse crystolon is probably the best bevel work stone I know of, though I haven't used stu's sigma stone (which is some type of silicon carbide like a crystolon stone). I'd personally rather have a medium crystolon, though, and use it a little bit more often.

That is surprising that the Sigma is a silicon carbide stone. I thought silicon stones had to be soft because the abrasive is so hard and brittle and breaks down. All the talk about it was how hard it was and difficult to lap. I have used loose, coarse SiC and it breaks down to polishing in under ten seconds. I would not want that securely bonded on a coarse stone. I bought an old Crystolon by accident and it slurries fast. Well most of the time. It is quite a vexing stone as sometimes it is obnoxiously loud and fast and other times it seems to not work at all. It is at its worst after lapping it and seems to harden up. sometimes the spent slurry smears into the stone and i cant rinse or work it out. I am using it on backs though and i recall you seeing it does not work well on them.

Ian, chefkivestogo also has some uber coarse bench stones for flat bevels. By Nubatamo or something. Like 24 grit. It did not seem to slurry in the video. It looked almost like it was the texture of it that was grinding.

Steve, i did not so much make the grinder as assemble it. According to Carl Sagan everything is like that. "If you want to bake a pie from scratch, you need to create a universe." It is not cool at all. They are all kinds of neato multitask machines powered by bike. I have one of those grinders with a pulley in the middle and i just put a belt around an old bmx bike wheel as a fly wheel. The chain is attached to a treadle that is returned by a bungee (it is a freewheel hub [correct term?]). I also have one of the big sandstone wheels but it just throws water from the trough all over and empties it. It is too cold here as well to have a water cooled grinder. It is pretty slow as well yet puts some random deep scratches in.I happen to have some pics for craig'slist on hand.

299103299104299105299106299107

dan sherman

10-27-2014, 5:14 PM

That is surprising that the Sigma is a silicon carbide stone. I thought silicon stones had to be soft because the abrasive is so hard and brittle and breaks down. All the talk about it was how hard it was and difficult to lap. I have used loose, coarse SiC and it breaks down to polishing in under ten seconds. I would not want that securely bonded on a coarse stone. I bought an old Crystolon by accident and it slurries fast. Well most of the time. It is quite a vexing stone as sometimes it is obnoxiously loud and fast and other times it seems to not work at all. It is at its worst after lapping it and seems to harden up. sometimes the spent slurry smears into the stone and i cant rinse or work it out. I am using it on backs though and i recall you seeing it does not work well on them.

The Sigma Select II are silicon carbide, but I don't think the other lines are. If memory serves, The Select II's are sintered silicon carbide, and thus 100% abrasive. So, when it breaks down all it does is expose new fresh abrasive.

David Weaver

10-27-2014, 5:21 PM

Love the grinder!!

I saw some of those coarse stone videos from chefknivestogo, and though I've bought plenty of things from them, I don't think that there is any free lunch in their stones. A 24x stone is not really a stone that is going to work well with hardened steel - it's like saw teeth. You want the abrasive to be the appropriate number of points per inch in the stone or it's just rasping instead of uniformly abrading.

Stu hasn't told me anything about his stones, but the way they're described and looking at them, there's not too many things they could be. Silicon carbide stones are black, and off the top of my head, I can't think of much else that is. Getting the "count" of the points right can get a good fast cut with less break down of the grit for a little bit, but a stone that isn't a little friable and that doesn't have a heavy oil to move stuff will create a stone that clogs.

Old crystolon stones if they are old enough will be rock hard and cut like crazy and feel almost dangerous at first, but as the grit on the surface breaks down, they become slow, and because the abrasive is so friable while the aged binder is not, they become almost useless. All of my old crystolons are like that. They are also a bear to wake back up without other silicon carbide that is coarser, or at least something strong enough to rip the particles off.

Moral of the story being that stu provides loose grit to bring the stones back to life, and nortons newer crystolons are very friable and unsuitable for flattening things because of it (they can't bite deep enough for that, anyway). The crystolons are great for bevel grinding, though.

ian maybury

10-27-2014, 5:48 PM

Ta Noah, that's the coarsest of the coarse in stones all right: http://www.chefknivestogo.com/nuume25gr.html Wonder how its supposed to be flattened? Reminds me very much of the composition of the presumably silicon carbide stones with a handle we used to sharpen scythes, sickles and other (pre-strimmer) grass and hedge cutting devices in my youth. The bicycle power is neat. :) Must help to have a minion to hand to pedal while you focus on grinding!

It's an interesting question as to how heavy metal removal was handled back in the day - in that it's hard not to suspect that in the end any bench stone that's used manually can only be very slow indeed compared to what a powered grinder or belt can do - the work simply can't be moved fast enough over the stone for there to be enough cuts happening for it to be otherwise. The alternative might be for very heavy pressure to result in deep enough cuts, but that seems unlikely except in the case of very small blades and work areas.

As before the volume of metal to be removed/the area being worked makes such a difference. 'Fast' on a small tool/work area becomes dog slow on something much larger and thicker...

David Weaver

10-27-2014, 6:07 PM

In the past, cutlers had very large sandstone wheels running off of mill power.

Shops had smaller sandstone wheels or large coarse sandstone bench stones.

I've got a sandstone bench stone and it's quite fast with carbon steel. I'd imagine 18th century workers were quite good at avoiding damaging tools with nicks and chips and didn't spend much more time sharpening than we do.

dan sherman

10-27-2014, 7:35 PM

In the past, cutlers had very large sandstone wheels running off of mill power.

Shops had smaller sandstone wheels or large coarse sandstone bench stones.

I've seen a few of these wheels,and all them either used a water bath, or could be used with one. I'm betting that helped a lot.

David Weaver

10-27-2014, 8:09 PM

I've seen a few of these wheels,and all them either used a water bath, or could be used with one. I'm betting that helped a lot.

That and some luck in getting one that would shed its grit a little. Of course, these days, you could just go to home depot and get a very coarse rub stone out of the floor tile section for a few dollars. I don't know what the tile guys do with them, maybe clean up the edges of snapped tiles.

Those wheels were everywhere I went as a kid, I guess most farms had one for implements of destruction. I haven't seen many in good shape, except for one at the apple harvest festival north of gettysburg, there used to be a guy who would sharpen everyones' pocket knives. He'd put a big fat wire edge on their knives and grind away a whole bunch :eek: That was probably 25 years ago now, and the guy was charging a buck or two bucks for the service to put on an edge that looked like what you'd get off of a crystolon stone. His wheel cut fast, though.

Steve Voigt

10-27-2014, 8:31 PM

Noah, awesome grinder! Thanks for the pics!
I think I need some pedal power in my shop.

David Weaver

10-27-2014, 8:35 PM

80 grit CBN out of the box is too coarse. Cuts deeper than a pink 46 grit wheel.

When I got the pink wheel, it was on clearance for $13. I still like it the best of the options as far as the combination of heat, speed and finish.

I think folks would like the 180 grit CBN as derek says, though. Hopefully the 80 grit wheel will break in, but initially it's a bit coarse. I can literally feel bits of steel hitting my fingers as I'm grinding, and I'll be using safety glasses (something I don't normally do).

When you use it, it rings like a bell on a thick chisel.

Almost no heat at all, though. Barely even warm, you can just put the chisel on the rest and hold it against the wheel without moving it. It takes away the need for technique!

In a short year or so, I've already worn half an inch off of the pink wheel, which is no problem when they're $13, but a big problem when they're $45.

Reinis Kanders

10-27-2014, 8:53 PM

Where is a good place in US to buy the 180 grit CBN wheel. Amazon is out of stock.

Mel Fulks

10-27-2014, 8:55 PM

There is a water bath type grinder that turns up on ebay fairly often. Cast iron trough base ,like most of them I've seen it
turns so slowly it would be hard to over heat the steel even if you didn't use water. Nice beefy design,though.

David Weaver

10-27-2014, 9:33 PM

Where is a good place in US to buy the 180 grit CBN wheel. Amazon is out of stock.

I got mine from a guy who has a site called woodturner's wonders (you can find it by googling that).

The wheels take up all of the arbor on the baldor grinder, and with a thick washer leave the nut on about halfway (but it's tight).

They are incredibly heavy wheels, as all of them probably are.

Reinis Kanders

10-27-2014, 10:20 PM

Thanks. I found the website, just was not sure about it.
I have a 10 year old six inch ryobi grinder that I relatively decent. Do you think it is worth to get an 8 inch grinder and cbn wheel or should I get a six inch cbn wheel?
I am trying to make less mess in my basement so cbn seem to be the ticket.

ian maybury

10-27-2014, 10:22 PM

David Weaver

10-27-2014, 10:28 PM

It works well on a 6" grinder. I don't really know whether or not there's a real reason to buy another grinder. That's up to you, though. The slip that came with mine said they recommend an 8" slow speed grinder (I like the deeper hollow from a 6, though).

David Weaver

10-27-2014, 10:30 PM

Interesting write up on CBN vs. diamond and more: http://www.pferd.com/images/Praxis_Galvanik_72dpi_en.pdf

Seems to suggest that while CBN doesn't like soft metals or steels that diamond offers only short life on steel as a result of some sort of corrosion effect...

CBN (unfortunately) doesn't appear to be available on discs in the same way as diamond is on lapidary discs.

You could use lapidary diamond discs and just use them at a slower speed. At high temperatures grinding steel, carbon exits the diamonds and the topic of what happens next to it is subject to arguments (either migrates into the tools or dissipates into the atmosphere).

CBN is generally more expensive than synthetic diamonds, and other than use for steel at high speed, i'd rather have diamonds everywhere else. There's some traction for submicron diamonds for razors instead of pigments and diamonds, but that kind of thing is not for me (it's not unusual to see a small spray bottle of CBN for $40).

Mike Holbrook

10-28-2014, 10:34 AM

I got my 8", 180 grit CBN at the place Derek linked to:

http://d-waytools.com/tools-diamond-grinding-wheels.html

Dave Schweitzer is very helpful and offers nice videos both on his site and YouTube. I just got mine this weekend and I am in the process of mounting it and trying it out. Dave's wheels all have 1" holes. He sells precision made bushings to adapt the wheels to 1/2, 5/8 or 3/4". Dave sells 80 & 180 grit 1 1/2" wheels. The wheel I ordered has a 1/4" radiuses on each side of the wheel. Dave also tells me that although he does not mention it on his site he also has 10" wheels. Dave says the 8 or 10" wheels can be used on a Tormek. Dave also sells a 6x2x1/4" CBN hand hone that has 600 grit on one side and 360 on the other.

David Weaver

10-28-2014, 10:57 AM

Thanks. I found the website, just was not sure about it.

By the way, I noticed the website was a bit plainer. I contacted the guy through ebay on a best offer auction for a damaged wheel (that had shipping damage around the back side of the radius that a turner might care about, but we wouldn't), and then found his site after looking up the logo on the wheel because someone else bought the damaged wheel before he got to the offer I submitted. I figured if I wasn't buying the wheel listed on ebay, I didn't need to give them 10% of his money, they made their cut on the wheel I missed out on.

From the time I located his website to the time I had a radius wheel (like the ones being discussed) at my doorstep was two days. Since I have a grinder with a 1/2 inch arbor, I figured I'd rather buy a wheel milled to that than have to buy a separate bushing. The only thing I'd choose different on a second purchase is a 180 grit wheel instead of 80, but the grind is not so harsh by any means that you can't use the 80 grit wheel, it's just not necessary to have it that coarse when we do mostly light grinding.

Long story short, the website is legitimate and so is the guy. (I have no affiliation with him and he didn't give me a discount to mention him or anything).

Reinis Kanders

10-28-2014, 11:10 AM

Derek Cohen

10-28-2014, 11:14 AM

Thanks for the info Dave and Mike. I am now trying to decide on whether I should I go with and 8 or 6 inch wheels.
After some thought it seems that 8 inch wheels do not really have any real advantages since CBN wheel diameter does not change with wear.

Reinis

8" will create a shallower hollow. Put another way, the 6" wheel may create a deeper hollow that you might want.

Regards from Perth

Derek

dan sherman

10-28-2014, 11:27 AM

An 8" will also remove material faster than a 6" if spun at the same rpm.

Reinis Kanders

10-28-2014, 5:25 PM

Decided to go with 8 inch from Wood Turners Wonders, but now they are out of stock so I have to wait.
After I pulled it out of storage my grinder actually turned out to be 8 inch one which made my decision an easy one.

I was also looking at Sorby's belt sander setup because two CBN wheels and new grinder end up costing almost the same.

David Weaver

10-28-2014, 5:54 PM

I think you'll be happier with the grinder and wheels than the belt sharpener. No consumables, either. Two of those wheels in 8 inch size will have a ton of rotational energy.

ian maybury

10-28-2014, 8:24 PM

Thinking aloud to share some more on possible options for flat grinding bevels for anybody that may have an interest. Think there's several more or less DIY options that may be runners since there's not a lot ready made coming up. Thinking as well that bench grinder based solutions have a lot of potential - if fitted with CBN or low heat wheels, and possibly if run at low speed. (this latter might compromise metal removal capability more than is ideal for heavy jobs/but high speed may be OK too with low heat wheels)

1. Use a bench grinder, but fit one end with a cup or recessed centre wheel of appropriate type - and grind by moving the bevel (and dressing tool as needed) acros the side face of the wheel. CBN would be really nice, but may not be available in this format. (?) Hopefully something like Norton 3X is. This video is about building a fixture to hold lathe tools for grinding this way, there's pictures of the final rig around 7.00 onwards. It could be done more simply - not much more costly than a hollow grinding set up - but it illustrates the principle/layout: http://www.youtube.com/watch?v=JdoVWoUMBVs

One advantage is that the grinder would be available for other work, and would permit hollow bevel grinding if this was required also. Presume a 6in machine would be Ok, probably also high speed.

2. Adapt a belt sander with a properly set up platform from which to mount jigs and/or use a honing guide to set bevel angles. Getting quite a bit more expensive (belt systems inevitably have more parts and complexity), but perhaps advantages too if a Multitool bench grinder mounted item is used: http://www.trick-tools.com/Multitool_4_x_36_inch_1_hp_Belt_Grinder_Bundle_MT3 64_100_Bundle_5271#.VFAxq94kMlw A normal high speed single phase induction motor might be a better option than a bench grinder, in that it would permit VFD control of speed if required.

3. Adapt the currently used disc sander to mount a 10in dia diamond lapidary disc using self adhesive magnetic sheet (cooler and longer lasting and more easily changed than self adhesive abrasive discs - turns out that 10in discs are available from China on EBay), and add a VFD for speed control for lighter work.

Just flying kites while waiting for inspiration/insight to dawn. Hollow bevel grinding on a bench grinder is pretty clearly the simplest and most cost effective option.

george wilson

10-28-2014, 9:11 PM

8" grinders usually run slower than 6" grinders so their wheels don't fly apart.

Bruce Mack

10-28-2014, 10:20 PM

Just flying kites while waiting for inspiration/insight to dawn. Hollow bevel grinding on a bench grinder is pretty clearly the simplest and most cost effective option.[/QUOTE]
Hello Ian. As you have redone the 50 degree bevels of the Veritas irons, and do have the option of buying either 25 or 38 degree irons for your bevel up planes, I'm wondering if just the Shapton 120 with a jig or freehand might be sufficient to give you a flat bevel and remove small edge chips, allowing you also to remove microbevels if you choose? You're (we're) sharpening for only yourself and not a woodworking school.
I've valued the advice on this forum, especially David's. I can see myself successfully grinding a 1/2" chisel but not a 2 3/8" iron. To have any chance at the latter without gouges and serrations I would need an additional sliding guide attached to the tool rest. Reading reviews of the sub $100 grinders, I envision wobbly wheels from bent shafts or distorted fittings. I have bought too many mediocre goods to readily go that route again. These are just my thoughts, not meant to counter the observations of those adept at grinding.

bridger berdel

10-29-2014, 12:08 AM

Just flying kites while waiting for inspiration/insight to dawn. Hollow bevel grinding on a bench grinder is pretty clearly the simplest and most cost effective option.
Hello Ian. As you have redone the 50 degree bevels of the Veritas irons, and do have the option of buying either 25 or 38 degree irons for your bevel up planes, I'm wondering if just the Shapton 120 with a jig or freehand might be sufficient to give you a flat bevel and remove small edge chips, allowing you also to remove microbevels if you choose? You're (we're) sharpening for only yourself and not a woodworking school.
I've valued the advice on this forum, especially David's. I can see myself successfully grinding a 1/2" chisel but not a 2 3/8" iron. To have any chance at the latter without gouges and serrations I would need an additional sliding guide attached to the tool rest. Reading reviews of the sub $100 grinders, I envision wobbly wheels from bent shafts or distorted fittings. I have bought too many mediocre goods to readily go that route again. These are just my thoughts, not meant to counter the observations of those adept at grinding.[/QUOTE]

The skill to grind a decent bevel isn't too hard to acquire. It does take some practice, but don't assume that you need jigs.

ian maybury

10-29-2014, 7:38 AM

Ta George, add Bruce and Bridger's observations and it's pretty clear that a cheapest of the cheap bench grinder would not be a good choice. Need to buy a bench grinder anyway, as i've been getting by with a unit self built on a saw spindle about 35 years ago. We don't get the same choice here as in the US though - tends to jump from junk to expensive.

Guess I'm past the worst on the re-angling of plane irons Bruce, and the WorkSharp will certainly re-work bevels/grind off honing bevels. Against that, and given the way this stuff tends to shake out it'd seem a pity when going for a grinding solution not to get/build something with the full range of capability as sure as eggs some unforeseen need will come up.

On guides when grinding. Lots manage it freehand using a finger against the tool rest to guide the tool. Veritas and others do a grinding rest with a built in guide rail: http://www.leevalley.com/US/wood/page.aspx?p=32973&cat=1,43072,45938

I'm starting to sound like a commercial for hollow grinding and using a micro as opposed to single bevel - in that what's acceptable when bevel grinding depends a lot on what of sharpening method you are using. The hollow grind/micro bevel route has got to be a lot more tolerant of minor grinding inaccuracies. Single flat bevel sharpening in comparison on e.g. Japanese chisels requires a really flat and accurately angled grind if lots of remedial work when honing on the waterstones is to be avoided - especially if using a honing guide. The Veritas Mk 2 honing guide (but it needed some dialling in to sort out a roller misalignment) makes a good job of this on the top of the WorkSharp. I'm hoping a you have said that the 120 Shapton will prove fast enough for doing it too - it'd be much simpler and less prone to errors.

Flat bevel grinding/re-grinding of BU plane blades is also less critical/tolerant of minor misalignments if micro bevels are being used - it's the single bevel that ups the ante.

The insight that pops out of this sort of discussion is that even seemingly simple sharpening techniques depend on a whole series of stacked assumptions to work....

Mike Holbrook

10-29-2014, 10:40 AM

A couple questions about setting up these CBN wheels. I picked up a Delta 8" variable speed grinder the other day at Lowe's to try it out with the CBN wheel. I have not turned the new machine on with the new wheel yet as a couple things worry me a little. I still have the box and can return it.

Wheel guards
Most of the pictures I have seen of mounted CBN wheels are of grinders without any sort of guard. Either they are removed so that viewers can see better or they just are not needed or both. I have read, at least in the case of the 80 grit wheels, that sizable particles are removed. I imagine one can protect eyes, face and hands with a welders mask. I have the 180 grit wheel but I am considering the 80 too. It would seem like the clear plastic, see through guards might help, but on the Delta these guides attach to the inside wheel guard. On the Delta the outside guard has to be removed to mount a 1 1/2" wheel, but the inside guard can be left on, retaining the clear guards. I suspect the major reason for the wheel guard on grinders is the rare case of a stone wheel coming apart at high speed. I don't think the heavy metal CBN wheels are apt to come apart, even in the highly unlikely case of a crack so I suspect the main reason for these guards is a mute point on a grinder running CBN wheels? Were I to decide to use the Delta grinder without any guards on the side with the CBN I am not sure if it would be a problem to leave the guards on the remaining stone wheel. Dave mentions in his video that he does not feel it is a problem to run a solo CBN wheel on a standard 2 wheel grinder. If this is the case then I doubt leaving all the guards in place on one side of the machine will cause balance or vibration issues on the CBN wheel side. It does seem logical to me though that having two different shaped, different weight...objects on opposing sides of a spinning arbor must have some consequences. Ultimately I think having two CBN wheels of the same size and weight would be optimal but, I am not sure what differences not having equal spinning object might entail?

Arbor space
The 1 1/2" wheel I have fits on the 5/8" arbor fine (with the 5/8" bushing) but the bolt does not quite have enough room to get entirely through the nut. I don't think this is a big problem as the nut is engaging all but maybe one or two threads, still probably not optimum? On the D-Way web site Dave has a video on installing his wheels. In the video he says his wheels require 2 1/8" of usable arbor space, but he also has a message that comes on the screen saying that Dave meant to say 2" minimum. The Delta grinder has just a hair over 2" according to my Starrett square.

I am wondering if I should look into another type grinder with more arbor length on each side and a larger motor?

David Weaver

10-29-2014, 10:43 AM

There are substantial particles coming from the 80 grit wheel, I can confirm that. You don't want them to end up in your eye. I've been in the ER before with metal in my eye, it's a nuisance for several days after you get it removed. At a minimum I would wear safety glasses grinding with one and no guard, and I generally don't use safety glasses with my grinder - I stand to the inside of the guard so that no particle can get in my eye without at least having to bounce off of another surface and lose a lot of momentum.

(my eye issue was actually from metal particles coming off of a belt sander and not a dry grinder)

Derek Cohen

10-29-2014, 10:53 AM

David, how high up the wheel are you grinding? Off the 180 grit I get just a little fine dust, which goes straight down. The guard is off my wheel. Is yours?

Regards from Perth

Derek

David Weaver

10-29-2014, 11:13 AM

My guard is on. I grind where the stock baldor rests go, which is probably halfway up the wheel or a little more. I do have part of my cast guards on (there is no way the wheel would fit inside them), which is the inside half and I can avoid flying particles by standing just to the left of the rest (or rather putting my head there).

It's possible that the pieces that have hit me in the head have bounced off of something, most of what I feel us large particles hitting my fingers below the grind point.

The 80 grit wheel takes off big particles. You'd be surprised how deep it cuts. The grind marks must be twice as deep as the pink 46 grit wheel.

Derek Cohen

10-29-2014, 11:31 AM

mmm ..... David, there appears to be a big difference in our wheels. I wonder if this is the grit level (80 vs 180) or the make? My 180 creates a surface similar to the Tormek (which is 220).

Can you remove your guard altogether to determine if the grit spraying out is bouncing off this?

Regards from Perth

Derek

David Weaver

10-29-2014, 12:40 PM

I could remove it at some point. When I do, I'll report back.

I think your wheel and my wheel are made by the same place, and if not the same place, the same spec. I think the grit on my wheel is probably 2 or 3 times the micron size (based on a grit conversion chart, that would be exactly the case if the grits are graded properly - vs. 180 and 220).

When I look at the pictures of the radius wheel from ken rizza, the 180 and 220 grit wheels look very similar to the dway, much finer than 80 grit.

ian maybury

10-29-2014, 5:36 PM

It seems that grading of CBN wheels is a bit of a hit and miss job - one UK supplier of turning tools that I spoke to today really didn't want to talk in terms of grit sizes at all - just extra fine, fine, medium, coarse etc. Arguing that it doesn't correlate to performance (finish and metal removal rate) in the same way as with say AlOx. Which may well be the case, but means that it puts a lot down a lot to getting some experience.

I'm thinking seriously of trying a counterbored/recessed/cup wheel on a bench grinder solely for grinding new bevel angles (heavy metal removal - occasional requirement) and re-grinding bevels/grinding off honing bevels (moderate metal removal) on the flat/side/end face of a CBN wheel - it looks like there are some available in the UK with a roughly 15mm wide cutting band on that face. The CBN sounds very promising re. low dust, no wear, long life, minimal heating etc.

Do you think at this early stage that it's possible that a CBN wheel can handle the above (by AlOx standards) pretty wide range of removal rates off a single wheel on say a low (single speed) bench grinder? Or might it require say the 80g for occasional rapid metal removal on heavy pieces, and the 180g for regular lighter work/re-cutting the bevel before honing on waterstones? (two would be starting to get expensive)

PS Think i've answered some of my own questions. Digging through the turners sites 80 grit CBN is typically presented as being for 'shaping' tools, while the 180 is for 'sharpening'. Another complication emerging seems to be that only Optigrind do coated sides for side/flat surface grinding, but only in the 180 grit. The sharpening supplies guys seem to figure there's not much demand for side grinding in the 80 grit. There's far fewer 8in wheels about too.

Noah Wagener

10-29-2014, 7:08 PM

Ian,

You had mentioned grinding on the side of Norton 3x wheel. I bought one of those precisely for that. For jumpstarting lapping badly pitted tools. For some reason the side of my wheel mirror polishes. It may be the hard grade and finer (relative, it is 80) grit and larger contact area than intended. Even the intended grinding face of it is not much faster than a sandstone wheel.
That sandstone wheel i have is actually probably faster on my tools than the Norton when i use a lot of pressure but i can not keep the wheel spinning when i do that. Cooler running as well despite no water. I may experiment with a bigger crank but I ordered one of those Sigmas as they are only 25 dollars US with shipping and if that works as tauted i think i will clear up some space jettisoning the grinders.

ian maybury

10-29-2014, 9:26 PM

Thanks Noah. I thought of the 3x, but moved on to considering the CBN option based on Derek's very helpful comments. CBN wheels are made in lots of formats, including specifically for side/face grinding: e.g. http://www.cuttermasters.com/portfolio/cbn-grinding-wheels/ Norton have long lists of various types of CBN wheels too - it might even be a cheaper way to buy if we could tie down the required specification. Optigrind/Holzer Hartsstoffteknik in Austria (possibly ex of UK) also do some wheels with a band of CBN on the side as well as on top - they pop up in the catalogues of quite a few wood turning supplies places in the US and around the world.

One issue to be solved with using the side of a wheel in a material like 3x is that it presumably needs to be dressed to keep on cutting, but i'm not sure how this might be done. Wonder if your wheel was possibly glazing? (just a guess - i don't know how fast they cut when freshly dressed) Bench grinders and wheels may not be intended to handle much side force either, although it likewise may not be an issue.

More crank should increase your torque a bit, but might slow your eprson powered grinder down. Could help though. I remember building a pedal powered potter's wheel once - one immediate discovery was that the human body/our legs are very sensitive to getting the gearing right. Too fast/high and we can't turn it, but too low and we just as quickly run out of rpm. Maybe a ten speed grinder? :)

Noah Wagener

10-30-2014, 2:40 AM

Wonder if your wheel was possibly glazing? it is brand new. polished right out of the box. it is the first wheel i have ever bought and i do not know the standard operating procedure for them. maybe you are supposed to dress them when new.

maybe a ten speed grinder? :) That is what i originally wanted to do. i tried this:

299255

but i use my bike and did want to take of the fork. you can see how uncomfortable it would be leaning forward with the pedals behind you like that and with the fork on it was worse. plus you had to pedal backwards. i was not handy enough to mount a second wheel next to the rear wheel as a fly wheel.like these people:

http://cache.wists.com/thumbnails/7/cf/7cfd2387a0d9011a135ecac4b0ba5665-orighttp://cache.wists.com/thumbnails/6/92/6927617b06a3f6235de1379b9e1d9fee-orighttp://cache.wists.com/thumbnails/7/9c/79ccf493e681714bcc2e17b595ec3033-orig

Mike Holbrook

10-30-2014, 12:33 PM

I just talked to Ken Rizza at WoodTurner's Wonders. Turns out Ken is in Lawrenceville, GA not far from where I live. Ken's CBN wheels are a little different than the D-Way Tools wheels. Ken offers 1 1/4" wheels that fit on the newer shorter grinder arbors better. Ken's wheels do not require a bushing. Ken also offers 80, 180, 220 and 350 grit wheels. Ken's latest wheels, which apparently arrived just before my call, not only have a radius on the wheel corners but also have grit on a 1" area on the side of the wheel. The grit on the side of the wheel is for flat bevels. Another interesting product Ken sells is a 3 piece set of self-aligning washers that help keep grinder wheels running smooth without wobble. Ken's price for the wheels with the additional side grit are lower than D-Way Tool's for the regular radius edge wheels.

Mike Holbrook

11-01-2014, 6:23 PM

WoodTurner's Wonders (same .com address) has a picture of their new wheel on line now. This CBN wheel has rounded corners continuing into a 1" flat CBN covered area on the wheels side. Check it out in the catalog. The picture will zoom in for a close view and out for an over all. Then click the picture and get more info.

This one does not come with washers, but they have a special "Self Aligning Spherical Washer 3 piece set" (For One CBN Wheel). I did not figure this out so I guess I am ordering the 3 piece set now. I will post more information when I get the washer set and have a chance to compare the 180 D-Way to the 350 grit WoodTurner's Wonders. Ken informed me that he frequently uses turning tools right off the 350 grit tool so I went down vs up in grit for my second wheel. From what I have read I think the 180 will be great for forming new/different bevels and I am hoping the 350 will be great at refreshing and smoothing the bevels off the 180. From there I hope a few swipes on my Spyderco medium and extra fine stones will keep my tools very sharp very fast with little or no water. I may spritz my CBN wheels with water to consolidate the smaller refuse.

Yes, I am serious about being able to sharpen fast. Now all I have to figure out is what to use as a tool rest/guide. Derek apparently made something to hold a Tormek bar. I assume this allows him to use Tormek tool holding devices at his CBN grinder or Tormek. Dave at D-Way mentioned another jig that I have not been able to run down yet. Then there is the Lee Valley rest...From what I understand, the CBN wheels stay the same diameter so I am hoping there will not be the constant issue of adjusting to a changing wheel size. It might be possible to set a jig with a scale up and be able to switch between angle settings for different tools, BU plane blades at different angles....and not have to adjust it all the time. Yes, even more speed!

ian maybury

11-01-2014, 7:56 PM

Thank you very much for sharing that Mike - those WTW wheels are exactly the sort of thing I've been searching for in that they can handle flat bevel grinding off the sides.

This is the Lee Valley grinding tool rest i've seen: http://www.leevalley.com/en/Wood/page.aspx?p=32973&cat=1,43072,45938 Sorby do something fairly similar it looks like, but no idea how well it works: http://www.robert-sorby.co.uk/universalsharpsys.htm I've been toying with the possibility of setting something like the Veritas up at 90deg to the usual direction to grind off CBN wheel sides to do flat bevels - but it'd have to very accurately maintain its setting/reliably stay locked.

One issue from my perspective (probably not in the US where it seems many have 5/8 shafts) is to find an 8in grinder (the WTW sheels seem to be 8in OD x 5/8 in bore X 1 1/4in wide) with a 5/8in shaft and able to handle 1 1/4in width. It's hard to know whether or not the cheaper Eastern ones on offer are likely to be good enough - smooth enough running.

It could end up requiring getting the wheels bored out to fit a stock larger diameter reducing sleeve to match whatever grinder I guess - but would need a decent machinist to ensure it all was properly centred and fitted.

I've been thinking towards 80 grit in the CBN for fast metal removal/forming new bevels in plane blades, and maybe 180 for refreshing before honing - but don't know if this is a good call. (you are thinking finer) It'd be even better if a single wheel would handle both forming and refreshing bevels…..

The other call is whether or not to go for a low or high speed - the choice in the former is very limited here. Not sure which would be best with the CBN - the answer depends I guess on just how well the promise of very low heating is delivered by it, and on what else gets done/other stones will be run on the grinder.

The last (for now) question on CBN wheels is perhaps life - given the cost they definitely need to last more or less indefinitely as advertised.

It's more or less simultaneously emerged that the Sorby Pro-Edge looks like a decent option too - it's not cheap (similar to the cost of a grinder with 2x CBN wheels), but seems very well engineered and solidly built. There's a supplier in the UK doing belts for it in a wider range of grits and abrasive types than the stock items (e.g. coarser than the stock 60g) which should help widen up its capability. I'm inclined to doubt that the stock 700ft/min will remove metal fast enough for forming new bevels on plane blades when a lot of metal has to come off, but a VFD seems like it should (?) sort that out by maybe doubling the stock speed.

It's also claimed to be a 'cool running' solution, but the question I guess is (a) how cool, and (b) how fast cutting when equipped with say a coarse ceramic belt.

It really needs getting hands on with both solutions - there's otherwise (for me anyway) a fair amount of guesswork and hence risk involved in making the call between the two.

Decisions decisions.

Think i may have the opportunity to test run some CBN wheels during the coming week with a local wood turner who has some set up. It seems that Sorby's rep is demonstrating the Pro Edge in our local shop the coming weekend too, so maybe for once the stars are lining up...….

Steve Friedman

11-01-2014, 8:55 PM

Mike,

I'm not Derek, but he has his grinder set up with the Bench Grinding Mounting Set from Tormek. Here's the link to his site where he describes it. http://www.inthewoodshop.com/WoodworkTechniques/GrindingNirvana.html

I have spoken to the Tormek folks about it and it accommodates a few of their jigs. I don't know enough about the Tormek to understand why some jigs don't work with it. I have the LV one, but the Tormek one definitely looks like it might be better for carving tools with the Tormek jigs.

Steve

Steve

Edward Moore

11-01-2014, 10:56 PM

It doesn't matter if you burn the tool's edge.

You'll do it once, maybe twice. Then never again.

When you do burn a edge, you just need to sharpen it again a bit sooner. No big deal. If you are really pedantic about these things you could just grind it back a bit, which is only 10 minutes of your life gone.

If you sharpen with a honing guide then your grinding can be rough as guts. Just don't grind past the honed edge and use that as a visual reference for your progress. If you want to be more accurate you can clamp a honing guide onto your blade and reference that against the tool rest.

I have been using a hand-cranked grinder with a very course wheel and Veritas tool rest. It takes slightly more practice than a powered grinder because you can only use one hand but it is still easy to get a nice, even grind. You have precise control over the speed, obviously, so it is really difficult to burn the tool and you can grind right to the edge.

I also have Stu's 120 grit Sigma stone. It does cut very quickly indeed but it is unpleasant to use. The clogging problem is overcome by regularly lapping with course silicon carbide grit and by using the stone while almost submerged in water. For course flattening work it is excellent. (Although I suspect David's idea of using a steel plate and loose diamonds would work better).

I have only been playing with sharpening for a few years. I am still learning and improving. However, the grinding seems like the least difficult and least important part of the process. I don't understand why a special machine is necessary. Buying a Tormek for a home woodshop seems like buying a Lie Nielsen scrub plane (although the comparison is unfair because Lie Nielsens are, at least, pretty).

Incidentally, hats off to Derek's grinding. That is like the Platonic form of a chisel bevel.

Derek Cohen

11-02-2014, 1:14 AM

I have only been playing with sharpening for a few years. I am still learning and improving. However, the grinding seems like the least difficult and least important part of the process. I don't understand why a special machine is necessary. Buying a Tormek for a home woodshop seems like buying a Lie Nielsen scrub plane (although the comparison is unfair because Lie Nielsens are, at least, pretty).

Hi Edward

"Platonic form", eh :)

I must say that I have a morbid fascination with sharpening. It is my least favourite part of woodworking. I know it has to be done, and do not look forward to it. At the same time, working with sharp tools is a pleasure - there is something magical about a blade sliding effortlessly through wood to create a desired shape. The wood I work with is so abrasive that I have to sharpen frequently. Trying to use less-than-razor edges is a errand in frustration.

Now I disagree that grinding is the "least difficult and least important part of the process". Indeed, I consider it the most important. It is the key to all that follows.

Yes I know that some do not grind at all, and some use a different grinder, but that is simply because there are many methods of sharpening. When it comes to hollow-grinding-based sharpening, the hollow can make all the difference in the edge obtained.

Simply put, a hollow that is to the edge of the blade leaves the minimal amount of steel to hone. Getting to the edge without burning the steel and altering its temper is the challenge. Doing this on a wet grinder, such as the Tormek, is pretty easy, but it is slow.

Grinding a ragged hollow - where the metal has not been removed evenly - means extra work on a coarse stone to straighten the steel along the hollow. This also removes the hollow and increases the amount of steel to hone ... which leaves you back at step one with more steel to hollow. Slow.

There are a number of ways to achieve a good hollow, and one does not require a CBN wheel to do it. I've posted pictures of some pretty decent hollow grinds that were done freehand. I've been doing this for a while now. I would not recommend a beginner start where I am - not because I think that one should earn the skills first (that is advisable), but because what is right for me is not necessarily right for others. I do not love sharpening. I just want a fast way of getting back to the wood.

Regards from Perth

Derek

Mike Holbrook

11-02-2014, 9:32 AM

Exactly what Derek said only different. I agree with everything Derek said, in spades, except I actually like to sharpen. I know it may be a sickness, but I find it a little meditative. I may be a little OCD too, because I yearn for the same perfect bevels Derek's tools exhibit.

Flat Vs Hollow bevels
For me the whole argument about whether to hollow or flat grind has become a mute point. Show me a perfectly "flat" bevel! I look at it like matching edges for glue ups. We know we are going to leave the "matching" surfaces either a little concave or convex. We know slightly concave edges make a better glue up. We know convex edges tend to rotate when pressure is applied while concave edges hold together. For some of the same reasons, I think a slightly concave bevel is better too. I use to think a convex bevel was fine and might have some sort of advantage. What I have learned from doing things the hard way for quite a while is a convex bevel rocks around on a flat stone or wheel and prevents solid registration of the bevel against the sharpening devise. The hollow grind holds tight against a wheel or flat surface, making registering the tool much easier. I also prefer to sharpen by hand as much as possible which personifies any rocking issues. Try registering a concave and convex ground bevel against both a wheel and stone by hand and I think the difference becomes clear. Since I will not ever be able to regain all the steel I have ground off bevels trying to make a straight convex bevel I finally decided to try it the easy way. So for me, bevels are not just an important factor in sharpening they are THE factor.

Grinders
I have not been able to stir up much if any discussion of various grinders Ian. Everyone on SMC seems to use a different type and there seems to be very little loyalty to brands or models. I talked to both of the CBN guys about grinders and although they both mentioned slow speed grinders I understood that they both prefer to use higher speed grinders. Ken at WTW says he started making his wheels 1 1/4" wide vs 1 1/2" because grinder manufacturers seemed to be making arbors shorter on newer models.

Why CBN Wheels & which ones
Although I can not confirm via personal experience yet I hear that one can hand hold a blade against a CBN wheel without stopping while sharpening and not create enough heat in the blade to make it unpleasant to hold. The WTW wheel I just got came with a little card in it- Lifetime Guarantee. Dave at D-Way says he has sold thousands and has yet to have one returned because of wear. Assuming they live up to expectations, the CBN wheels start sounding like a long term bargain to me in terms of longevity, safety, ease of use, repeatability.... I wanted two wheels and decided on the 350 grit as my second wheel via discussion of my needs with Ken at WTW. I want speed and the 80 and 180 wheels may leave deep grooves in the steel that my Spyderco finishing stones may not remove easily, slowing me down. I understand Ken uses a 350 as his second wheel and finds the edge it produces works as a final edge for his turning tools. The little I have read suggests that grit changes on CBN wheels may not provide the same difference in grinding aggressiveness as in other wheels. I elected to go down to 350 instead of up to 80 for my second wheel because I think the 350 will quickly produce a surface that my Spydercos can polish easily/quickly. I suspect the new WTW 1 1/4" wheel is heavier than the D-Way 1 1/2" wheel. The WTW wheel has a solid metal 1" edge, which is covered in abrasive. The solid 1" metal edge adds substantial weight on an 8" wheel.

Tool Rests for grinders
The information I read on LV's tool description of their general purpose tool rest suggests that their rest has a 1" opening for the wheel, which may not accept my 1 1/4 & 1 1/2" wheels without modification. I am still trying to locate the rest Dave at D-Way tools uses in his CBN wheel demos before making a purchase.

David Weaver

11-02-2014, 9:51 AM

I have something to do today that should give an idea about heat buildup.

A while ago, mel fulks sent me a couple of chisels in trade. They are both 1/2" timber framing mortise chisels that he found in his travels and he mentioned that he already has enough of such a thing that he'd pass them along, and thus he's got no use for them and hasn't used them.

I looked at the one and got a chuckle, the yard saler who sold them to him had ground the bevel upside down on one of the chisels - they are the type that has a curved taper along their length, and I'll bet the person using that chisel wondered why the bottom of the chisel "wasn't flat" :D

So, I figured I'd set it aside because there's two and one has the bevel on the proper side.

I will sometime today take the chisel that has the bevel on the wrong side and hold it against the wheel and literally grind the entire bevel off and grind another one the other way (effectively two entire bevels of work), and I'll see how much heat is generated and how long it takes to do that. I'll check the loupe then and see if there are any temper colors anywhere near the final edge.

This is a job I haven't done yet only because I don't have water at my grinder and this literally would've required it and some discretion in grinding. With a regular wheel when grinding something like this, i grind in facets so as to work a small surface at a time and build less heat (though I won't do that with the CBN wheel), and only grind the full bevel as I'm finishing the grind.

The other thing about that kind of work is while a pink wheel like I like to use leaves a nice surface and doesn't build up a lot of heat, heavy grinding wastes a pink wheel if you get heavy handed with it.

ian maybury

11-02-2014, 10:21 AM

Have to agree Derek - ability to sharpen effectively is arguably the primary gateway to working to a high standard. Also that grinding matters a lot. Depends on what you're shooting for, but it's got to be a big deal/the foundation if you ony want to run very fine micro bevels like you showed with the Spydercos, and that has the side benefit of minimising the need to regrind. Likewise when sharpening chisels single bevel the ground surface must be flat and very accurately aligned/angled, and that angle accurately transferrred on to the waterstones (hence my interest in using the Veritas Mk 2 guide to align both grinding and honing without disturbing the tool in between - not sure yet how to do this on CBN wheels) to avoid the need for lots of waterstone work.

Sharpening has a certain sort of fatal fascination for me - boring, but also highly dependent on doing it just right. There is something deeply satisfying about seeing a polished micro bevel emerge, and finding that it delivers a wickedly sharp edge.

Be careful of your CBN wheel David - although your information Mike suggests that the things are pretty much bullet proof. Agree that if they balance properties as claimed (balance of heat/metal removal/speed insensitivity/wear/cleanliness/life/safety) that they are a vey attractive proposition indeed. The safety issue is no minor factor.

Reading what gets published (says a lot when a mag refuses to apply a rating) the problem on DIY/hobby grinders it seems to be that it's very easy to get stuck with one that's not very well balanced, or has runout/poor fits. They are pretty much the primary example of a power tool made down to a price i think. Those Baldor ones Tools for Working Woood sell look great, but the price tells all. One of the UK turning supplies outfits sells a budget one that they say they check before shipping. As ever it's not a big deal if you can buy up the road, but is a disaster if there's significant shipping cost involved. Turns out there are some grinders on sale in the UK with a 5/8 shaft, although so far all are std speed and run narrow 1in or so wheels.

It'd simplify things a lot of it proved that stock RPM was OK on an 8in grinder - but both David and Derek are on Low speed with 8in CBN wheels.

It'll be dead interesting to hear how you get on in terms of heating and rate of metal removal David. It's at the centre of the decision as to just how coarse a CBN wheel is needed to shift large amounts of metal - in that once the metal removal and heating rates are acceptable then the finer the better..

David Weaver

11-02-2014, 12:02 PM

I just ground the chisel, literally a triangle of hardened steel a quarter inch thick and an inch long. Halfway through the chisel was too hot to touch, so I brought a spray bottle over and sprayed the chisel every 5 seconds or so.

Total grind time was about five minutes, no tempering colors appear anywhere on the chisel.

Ian, large amounts of metal should only be removed as a matter of practice when steel is annealed, and I wouldn't want to use a nickel electroplated wheel on soft metal.

Too much of what I did today would probably result in short wheel life.

Mike Holbrook

11-02-2014, 1:03 PM

Thanks for making the mega check on these grinding wheels David. Sounds like the pre press was fairly accurate. I can't even imagine grinding that much hard steel that fast. I had to grind something like 1/8" off a Japanese mortise chisel, with a broken corner. I did it with a 120 grit DMT Dia-Flat Lapping Plate. It took 4-5 much longer sessions over two days to get the job done.

So who has tried a Japanese chisel or plane blade on one of these wheels? I am wondering about the softer steel not the harder steel.

David Weaver

11-02-2014, 3:28 PM

I haven't done anything not fully hardened yet.

Here's what the grinder looked like after the buildup of the swarf:

299414

I spray water freely around my grinder. There's enough loose metal dust, etc, that comes around after this that the rust is never around very long. The spray is only focused at the wheel, not up at the arbor. If there was every anything more than what's on the rest there, I'd stone it off with an india stone or something, anywah.

That matted bit of stuff between the rest and the wheel, here's what about 2/3rds of it looked like...it feels as though it's stuck together like a piece of foam rubber and you can tear it apart like that. When you're grinding, the top layer of it is spark, I don't know what's holding it together, maybe the heat of the sparks.

299415

The finish of the wheel is better now than it was when it was brand new. The deep grooves could've been rogue plated particles, or maybe I'm just getting used to the finish of the wheel.

Steve Voigt

11-02-2014, 4:33 PM

It doesn't matter if you burn the tool's edge.

You'll do it once, maybe twice. Then never again.

When you do burn a edge, you just need to sharpen it again a bit sooner. No big deal. If you are really pedantic about these things you could just grind it back a bit, which is only 10 minutes of your life gone.

Exactly. The fears about dry grinding are so overblown, though I am sure they are useful to the purveyors of expensive alternatives to dry grinding.

I have been using a hand-cranked grinder with a very course wheel and Veritas tool rest. It takes slightly more practice than a powered grinder because you can only use one hand but it is still easy to get a nice, even grind. You have precise control over the speed, obviously, so it is really difficult to burn the tool and you can grind right to the edge.

I bet your results are just as good as those spending hundreds or thousands more than you've spent.

I have only been playing with sharpening for a few years. I am still learning and improving. However, the grinding seems like the least difficult and least important part of the process. I don't understand why a special machine is necessary. Buying a Tormek for a home woodshop seems like buying a Lie Nielsen scrub plane (although the comparison is unfair because Lie Nielsens are, at least, pretty).

Agree again, though I don't want to minimize the importance of good grinding technique, because that can save gobs of time.

Great post! This is only your 3rd? Looking forward to more!

ian maybury

11-02-2014, 4:49 PM

Thanks for being so brave with your (80 grit/low speed grinder?) wheel David. I won't be able to go at it like that in my trial later this week as it'll be somebody else's grinder.

That's mighty impressive - much more aggressive than presumably most users would try anyway. Especially given the relatively narrow chisel. My tendency would be to seek to form a bevel in passes - out of caution. The chisel bevel looks very decently finished as you say too - tends to suggest that the 80 grit wheel alone might be a reasonable choice for bevel grinding once run in. There's two sides to that: (a) cost saving, but (b) it leaves the other end of the grinder free to put a stone on for more general purpose mild steel and other grinding - presuming you have one grinder.

The other positive is the almost (from this distance) pristine condition of the wheel after what (especially with a narrow workpiece/high pressure) was probably a very decent work out. There's no very obvious change in look/colour around the corner where presumably you didn't grind. A look with a loup would be interesting - did it tear out any grits for example?

I've seen a build up a bit like you got when heavily grinding mild steel fabrication parts on a std carborundum wheel, except that yours looks less tightly bonded together. My impression then was that it was caused by molten or almost molten particles of steel bonding/sintering together - suggesting that a lot of the heat is transmitted into the grinding dust...

David Weaver

11-02-2014, 4:51 PM

I think I get edward's sentiment, that grinding is just something you need to do and you need to get on with it sometimes.

i do agree with the other comments, though, that getting precise allows you to sharpen with anything. I can sharpen modern steel with oilstones or japanese natural stones as easily as I ever did with synthetic stones, and with more control. It's worth really getting the results in order and whereas the comments used to be about not waiting to go to the stones (as in never work with a dull tool), I'd say it's critical to me to not wait in going to the grinder. 3 or 4 hones on a grind and back to the grinder again rather than working a large area of steel.

Mel Fulks

11-02-2014, 5:16 PM

Good to see them ready for employment!

ian maybury

11-02-2014, 5:17 PM

A PS on grinders, especially @ Mike:

It's as you said very difficult to find (especially over here) a decent grinder that doesn't cost an arm and a leg, but which at the same time is good enough to at least be a predictable quantity in terms of runout and balance.

Creusen in Holland do some well regarded models, but they are not I think sold in the US. They don't have a low speed in 8in, but this seems not to matter given David's result. It's unclear whether their 8in model has enough shaft length to handle 1 1/4in wide CBN wheels. The underlying shaft is 15mm dia, which if accurate is inconveniently just smaller than 5/8in. (which might possibly explain why they are not sold in the US) : http://www.brimarc.com/products/Creusen-HP7200T-Powerline-Grinder-22330.htm

The stand out option coming up for me (in a somewhat higher priced/higher spec/better quality but not daft money grinder) is the 8in Metabo DS 200 bench grinder which is also sold in the US. It's a normal speed (3,570 rpm in the US on 60Hz, 2975 rpm here on 50Hz) grinder. Might be worth putting some time into adapting one (presuming it's practicable) if it's as smooth as in the first video below. (PS added later - both David and Derek are usig low speed grinders - so that probably rules out the Metabo - see below)

It lists 32mm grinding wheel bores, and it isn't clear if it has enough shaft length to handle a 1 1/4in wide wheel. Looks judging by the parts list below like the 32mm bore comes from a wheel mounting and spacing sleeve slid over the actual shaft. Could be that the sleeve can be machined to suit the width WTW CBN wheels - but questions remain. What diameter is the underlying shaft, and is it long enough given that the stock wheels are 1in wide.

I plan to phone Metabo in the UK tomorrow to enquire, but in the meantime it'd be great to hear from anybody who has one....

Some DS 200 Metabo related links:

http://www.youtube.com/watch?v=Ufx6CSm8TSM (hear one running - 0.41 and on)
http://www.youtube.com/watch?v=rBw1QPDqTfY (lousy voice over)
http://www.ereplacementparts.com/metabo-ds200-19200420-8inch-bench-grinder-parts-c-8879_9109_291299.html

ian

Mike Holbrook

11-02-2014, 6:10 PM

I found the Metabo DS 200 over here too Ian. The information I found said it ran at 3750 rpm, faster than the average which is why I stopped looking at it. I will probably stick with the Delta 8" Variable Speed Grinder for now. It runs smooth with the new wheels on it. I tried putting a washer on it since I did not have a penny and it stayed pretty much in the same place. It runs fine without being bolted down, although I will probably bolt it to some surface sometime so I can position a tool rest consistently. It seems to have as large a following as anything else and I know people who have used one for many years. The 2000 low speed is a little faster than most low speeds but it is nice to be able to turn the speed up or down. The arbor on the Delta may be a hair short for the 1 1/2" D-way wheel but I believe I can fix that easily with a thinner washer or different bushing that I understand D-Way makes for short arbors.

ian maybury

11-02-2014, 6:45 PM

Thanks Mike. I was suffering brain fade. David and Derek are both using slow speed grinders with 8in dia CBN. I've added PS to my posts above so as not to mislead. Pardon me.

For anybody looking in from over this side - another look turned up this low speed 8in/200mm dia x 1 1/4in (32mm) width wheel grinder in the UK from Axminster one of my usual suppliers. Not sure how i missed it: http://www.axminster.co.uk/axminster-trade-series-at8srg2-slow-running-grinder May not be the right shaft size, but that's fixable. Trouble is I've seen a very similar example get bad press from Derek for rough running, so it needs checking out.

No sign of any reviews of it - but their house stuff is normally pretty good...

ian

ps another Australian grinding jig: http://www.woodworkersinstitute.com/images/WT/articles/OptiGrinder200mmSlowSpeedBenchGrinder/gallery/IMAGE-2.jpg

David Weaver

11-02-2014, 7:20 PM

I'm using a regular speed 6 inch grinder, which isn't much different in wheel speed than an 8 inch slow speed.

I didn't notice any damage or stripped grains on the wheel, but it does seem to be a little more broken in on that spot. Still cuts (and sparks) plenty, though.

My grinding is definitely not any harder on the wheel than the round scrapers, etc, that only have one point of contact on the wheel. I just ground that by holding the chisel against the wheel.

ian maybury

11-02-2014, 7:46 PM

Thanks for that David

David Weaver

11-02-2014, 9:00 PM

Good to see them ready for employment!

They are very nice chisels, very cleanly finished. I already have a 1/2" timber framer, but it is unmarked and not as nice.

ian maybury

11-04-2014, 8:03 PM

Just to report on the brief trial run tonight on a very helpful wood turning contact's CBN wheels fitted on an 8in 1,425 rpm slow speed bench grinder (he's been running the fine one sharpening turning tools for months and reports no signs of wear) - in this case one was a 'fine' Optigrind. Probably the 'fine' 8in listed here http://www.toolpost.co.uk/pages/Grinding_Systems/O_Donnell/Grinding_Wheels/grinding_wheels.html They don't grade in terms of grit - but it looks like 180 or maybe even finer. The other a very coarse CBN wheel by another unknown maker.

I brought an old bevel down plane blade to play with. Basic observations:

1. CBN removes a lot more material than aluminium oxide for a given grit size - for very little pressure, and very little 'drag' on the wheel. The fine wheel above cut much faster than for example 80 grit AlOx on a belt sander, and with almost no sparks - it cut a new bevel on a 3mm plane iron in minutes. It'd be even faster to re-face a bevel/remove a honing bevel. A CBN wheel reportedly significantly speeds up a Tormek compared to the stock wheel too.

2. Heating as David found is very low. Three or four passes across the wheel formed the bevel, but the blade by this stage was just on the hot side of warm. Still easily handled - which means significantly less than 60 deg C. Very impressive.

3. The price of this free cutting and low heating seems to be (for a given grit size) deeper cuts/scratches in the surface than would be the case with even a much coarser AlOx grit. i.e. AlOx grits seem to break down quickly, and to as much 'wipe' material off the surface as cut it away. This possibly smooths the resulting surface somewhat, but probably also contributes to drag/friction and heating. My guess is that the CBN grits remain intact/function much more clearly as individual cutting points. (?)

4. The coarse wheel (which was new) was much more aggressive. It removed material significantly more quickly, but produced more sparks (still low heat) and left a very obviously grooved surface. i.e. running a thumbnail at right angles over the grooves resulted in obvious bumping/clicking. Rough enough that I think I would (guessing since the option wasn't available to hone the blade) prefer to use something finer before moving to honing on waterstones - for fear that it would require significant honing to get back down to a smooth edge and undisturbed metal.

5. Grinding throws out signfificant amounts of metal dust - enough to 'taste' half an hourafter working. Steel dust/mill scale is not harmless: http://www.gerdauameristeel.com/products/msds/docs/Mill-English/Steel%20Mill%20Scale%20MSDS%20_NA_%202-15-12.pdf CBN dust is likely not good either - there's some cobalt, boron plus all sorts of metals in there. My insincts are to wear a decent dust mask, and to ensure that I have enough extraction in the area so that the air is moving away from me.

It's very hard to draw definite conclusions based on this limited test and since there is reportedly quite a lot of difference between different maker's wheels, but i've decided to invest in a grinder and some wheels. On the basis that presuming it lasts well CBN seems definitely to offer the ability to remove metal fast enough with low enough heat input to efficiently get the heavy bevel forming jobs done that have previously caused me problems - while at the same time remaining controllable on smaller tools.

I'm going to buy an 80 and 180 grit pair because shipping is expensive to here, because for me the ability to remove metal quickly matters (not necessarily everybody) and because there's discount from Mike's source for a pair: http://woodturnerswonders.com/products/copy-of-cbn-wheel-4-in-1-design-180-grit It's possible however that something like the 180 alone would cover most normal sharpening requirements for many people, and leave the other end of the grinder free for a more traditonal stone for knock about grinding - hard to know.

Separately I got lucky on sourcing a grinder - it turned out that a fairly local supplier (unusually) had a stock of the above 8in low speed 1,425rpm bench grinder. He even helped me by doing most of the work in hand picking a good one - we ran a few with the wheels off to check for a true running shaft and reasonably well balanced motor. I'm sure it's very normal with budget eastern bench grinders, but the test tended to suggest that they vary quite a lot in this regard. Also that any underlying balance and true running issue can easily be greatly worsened by loose fitting and/or imprecise wheels and spacer sleeves. I've a sneaking feeling I'm goingt to end up turning up a set of accurately fitted spacers/sleeves.

The latter is likely to matter quite a bit with CBN wheels - any 'bounce' will reduce control, and tend to wear only one part of the wheel. Bottom line - it's not for nothing that an accurate grinder like a Baldor or a Toycen Tradesman costs lots of money….

ps some more grinding rests: http://www.woodworkersemporium.com/woodworking_tools/Woodworking_Sharpening_Tools?page=2

Mike Holbrook

11-05-2014, 12:35 AM

A little more information on the new WTW wheels arrived in my email. Apparently the wheels with the thicker edges were quite heavy so Ken elected to change the metal his wheels are made from. I thought the new wheel I got looked like aluminum and according to the latest info. on WTW that in fact is what it is. According to the information I was recently sent from WTW the old wheels were almost 8lbs each and the new ones would have been even higher so they elected to use 6061 aluminum. Apparently the electroplating process works better on aluminum too. I think the inside corner of the new wheel may be a little different than the standard 1/4" rounded edge if I am understanding the new information:
"There is a 9 mm 90 degree gap (about 1/3 of an inch) space shoulder on the inside edge of the grinding wheel for making relief cuts or tapers on hook type scrapers or box scrapers."

ian maybury

11-05-2014, 5:29 AM

Ta Mike, will have to check that out. Another snippet from last night prompted by the thought of aluminium. (although WTW's rims are so thick it's unlikely to be an issue) Seems it's not unknown for a machinist to put dents in the working surface of some of these wheels when machining the bore leading to three 'bumps' - sounds like some care is needed when chucking them, at least the ones with thinner rims..

Mike Holbrook

11-05-2014, 8:35 AM

WTW offers a set of three washers or two sets of three for two wheels that may help with wheel wobble issues. My D-Way wheel is a thread or two oversized for my Delta arbor, using the supplied bushing and huge washer. My WTW wheel is not quite wide enough to reach to the threaded area and nut. I ordered the WTW double set of washers hoping to get that perfect fit and balance both wheels in the process. "The spherical washers act as a ball and socket to compensate for slight misalignment and to eliminate undue stresses from the shaft nut".

I guess time will tell in regard to using aluminum for the wheels. It worries me a little in terms of the metals hardness but if the plating works better, it reduces weight and possibly dissipates heat better the positives should outweigh the negative. Ken did tell me he has been testing his new wheels a while so hopefully there will not be any big surprises.

ian maybury

11-05-2014, 5:49 PM

I guess it'd be important that aluminium wheels didn't result in any risk of displacement or tear out of grits. The softer material mght be more prone to getting scraped or gouged, but that should only happen if the grits were somehow removed by which point the damage would probably already be done anyway. Presuming a decent bond the grade of alloy could make a big difference. A decent heat treated high strength alloy should have very comparable strength to mild steel, but it tends to be quite a bit more flexible/less rigid.

The relatively light pressure required to get good cutting and the low drag/friction should help a lot, but time will tell...

Reinis Kanders

11-06-2014, 1:05 PM

I received my new wheel and a grinder yesterday. Wheel is 180 grit 4in1 from the woodturners wonders (WTW), grinder is Steel City industrial 8 inch low speed grinder.
Wheel is lighter than I thought it would be. Mounting it was a bit of a fiddle because it has in-between size of 1.25", Arbor had too much space even with the spherical washer set from the WTW. I actually ended up using a flange washer from the grinder to make things work until a more permanent solution. So in conclusion I wish I had bought a wider 1.5" simple radius edge wheel made from steel, which I will do for my 80 grit wheel. Advantage of this smaller wheel is that I can grind on the sides and wheel guards fit. I think I will use the wheel guard to keep the dust to minimum since this grinder has a dust port. Wheel does grind nicely, vibration is minimal, etc. I did not do any extensive grinding yet because I need to setup Tormek grinder rest.
Steel City grinder is pretty decent. Has thick, big machined arbor flange washers, that have weights in them to tweak wheel stability. Grinder is quiet even with the stock wheels. Pretty decent, no Baldor, but way better than my old 8 in Ryobi.

Mike Holbrook

11-06-2014, 2:11 PM

Interesting that the Steel City grinders arbor was still too long even with the WTW washer kit. My Delta Variable speed's arbor was just a few threads too long to work with just a bolt & 1 1/4" wheel. It should be fine with the WTW kit. The 1.5" D-way wheel is a couple threads too wide with the large washer and bushing that came with it. I hope I can work out a little better fit with my other WTW washer kit, which I hope to get later today. The D-Way washer is about 1/8" wide and the bushing on the other side protrudes about the same amount, so together they use 1/4" of arbor space. Apparently the arbors on these machines can be significantly different in length.

Ian I am wondering if the electroplating might be the determining factor in terms of grit staying put? If so, the aluminum, according to the WTW information, actually enhances that process.

David Weaver

11-06-2014, 3:15 PM

You guys who are turners could probably make a pretty nice washer out of brass or corian.

Steve Friedman

11-06-2014, 3:16 PM

Mike,

Did you end up getting two wheel? One D-Way and one WTW? I am torn between them. I like the flat on the side of the WTW, but not crazy about losing 1/4" of width. On the other hand, my grinder is only 1/2 HP, so the lighter weight wheel may be a big plus.

Steve

David Weaver

11-06-2014, 3:24 PM

I have the wide one from WTW, and my arbor nut is only halfway on (it's tight though). I'd rather (on a 6" grinder) have the 1 1/4" wide wheel, as the one I have is 1 1/2.

Steve Friedman

11-06-2014, 5:40 PM

I have the wide one from WTW, and my arbor nut is only halfway on (it's tight though). I'd rather (on a 6" grinder) have the 1 1/4" wide wheel, as the one I have is 1 1/2.
Why? Just because of the extra weight or because the shaft is so short?

Steve

David Weaver

11-06-2014, 5:50 PM

Because the shaft of the baldor is short. Weight doesn't appear to be a problem.

To be honest, I'm perfectly happy with it, anyway. It's a new product that does just what it advertises, and is really nicely made. I wouldn't buy another one just because of the width, it's not as if it's going to come off.

Mike Holbrook

11-07-2014, 4:02 AM

Yes Steve, I have a D-Way 1 1/2" 180 and a WTW 1 1/4" (4 Way) 350. I was out of town touring colleges with my daughter for a couple days and have not had a chance to test them yet. I just got the washers I ordered from WTW today and spent the little time I had playing around with them. I will be calling Ken with a question or two about those tomorrow. If I like these wheels as much as I think I will I may buy an 80 grit wheel for my Tormek. I'm not sure if WTW makes a wheel to fit my Tormek but I understand D-Way does. I run a 12 acre dog park and have lots of tools other than woodworking tools to sharpen: hoes, shovels, axes, splitting mauls, machettes/kukras, shears, mower blades, scythes.... I also like green woodworking which employs inshaves, large gouges, spokeshaves ( one of mine has a 5" blade), travishers, adzes, axes, drawknives...I may have more to sharpen than the average woodworker.

I like the 1" flat edge on the WTW wheel, I'm not sure how much I will actually use it but it is nice to know I can grind a flat bevel/side...if I decide I want/need to. I don't think the 1/4" difference in width will be significant. The 1 1/4" wheel definitely fits on the Delta arbor much better even using the extra wide 3 washer set from WTW. Apparently the Delta arbor is a little longer than David's 6" Baldor arbor, as the nut on my D-Way 1 1/2" wheel makes it through all but maybe one nut thread which I imagine is plenty secure. My arbor has 2- 2 1/8" available for wheel, washers & nuts.

Mike Holbrook

11-07-2014, 10:16 AM

Steve Friedman

11-07-2014, 10:49 AM

I don't have a tool rest yet, but I could not resist trying out the CBN wheels on a real blade. I took the Stanley SW blade out of my #5, the longest blade I have, and worked it lightly on the 350 CBN wheel.

Just what I was hoping for. I immediately see the result of the wheel on the bevel of the plane blade. One of the difficult things for me in the past was grinding away on the Tormek, or a coarse waterstone for quite a while and not seeing much result until I finally figured out my bevel was not where I wanted it. Because these wheels cut so much faster it is much easier to see the results of even a single light pass over the wheel. With the slower cutting mediums all those extra swipes tend to hide the over all pattern being created. The feedback, even with the 350 grit stone, is immediate.

Of course the other missing piece of the puzzle in my situation is a tool rest that will allow me to repeat passes at the same distance and angle to the stone. I am taking the fact that Lee Valley just posted a free shipping offer as a sign and ordering a Veritas Basic Grinding set which includes: the tool rest, a grinding jig and the jig for setting angles.
Don't you just love it when you get signs like that?

Thanks for the report on the wheels. I was actually thinking of getting the 180 and 350 from Ken because the cost of the second one is only $150, but then I would need two platforms.

Just another FYI for anyone (like me) with an odd-ball 7" grinder. Dave indicated that he makes a 7" wheel, albeit without the rounded edge. I'm going to get an 8" because it will fit with the housing removed.

I am really tempted to try the Robo Rest rather than the Tormek jigs because of the cost difference and simplicity of setting the angle, but think the Tormek may be worth the extra cost just to reduce the human error factor in getting repeatable results.

Steve

Derek Cohen

11-07-2014, 10:54 AM

Hi Steve

Get the Tormek rig. Look at the set up I have. I can switch between the blade holder, which creates a perfectly even grind, or I can slip on the flat tool rest, and use it like a regular tool rest. The Tormek angle finder enables you to set exact and repeatable angles very easily. And then you also have the option of all the other Tormek jigs.

Regards from Perth

Derek

Steve Friedman

11-07-2014, 10:56 AM

Mike Holbrook

11-07-2014, 3:17 PM

Derek,
Did you buy an extra Tormek rest or are you using the same rest and jigs, moving them between the two grinders? I figure there are two wheels, so I still have to figure out what I will do at the second wheel. I thought i would rig something like Derek has at my second wheel, with the Tormek rest and jigs I have and see how I like using them on the CBN wheels.

Derek Cohen

11-07-2014, 7:12 PM

Hi Mike

The kit from Tormek comes with a single arm and (I am not sure about this) a single base. I have a vague memory of purchasing a second base for the other wheel.

Tormek BGM 100: http://www.tormek.com/en/accessories/bgm100/index.php

I have toyed with the idea of purchasing a second arm so that both sides may be set up independently of one another. In this photo the second arm is borrowed from my Tormek ...

http://i13.photobucket.com/albums/a262/Derek50/Sharpening/CBN%20Wheel/2_zpsab867457.jpg

In practice it does not work well to have two arms as, being coplanar, they get in the way of one another when removing or replacing either the blade holder or tool rest. So the simple solution is the cheaper one: a base for each side and one arm.

Regard from Perth

Derek

ian maybury

11-07-2014, 8:00 PM

Just to say that i've done the deed and ordered the 80 and 180 grit pair of CBN wheels (chickened out on betting whether one or other alone would do the job) from Ken Rizza at Wood Turner's wonders - the key point for me being that they have the previously mentioned roughly 1in wide strip of abrasive on each side which should permit face grinding flat bevels, and the grits will hopefully enable rapid metal removal (e.g. re-angling bevels) and/or finer re-cutting/finishing of bevels as required.

I enquired about the durability of the aluminium wheels, Ken confirmed that they have never seen a problem and that the wheels are guaranteed for life against failure of the bond holding the grit - but obviously not against normal long term wear and tear in use. He also indicated that they are manufactured to an overall tolerance of significantly less than 1 thou (e.g. in terms of runout/eccentrictity and side to side wobble) which sounds excellent - the grinder is unlikely to match that.

Flat grinding requires moving the tool across the face of the wheel as on a disc sander - with a bar/miter slot/something to guide whatever is holding the work. Re. Derek's use of the Tormek fixtures. I have most of them from years ago - hopefully they will prove useful off a bar placed at right angles to what Derek has and be able to handle this face grinding situation also. (need to think it through) One fallback if it proves problematical might be a cast iron table and tilt adjustment from a deceased 10 or 12in disc sander...

Derek Cohen

11-07-2014, 9:06 PM

ian maybury

11-07-2014, 9:18 PM

I agree entirely that it complicates matters Derek, although if the face grinding CBN wheels and Tormek accessories work out as hoped for it won't once the method has been sorted be by very much. It's more that using CBN wheels to grind flat bevels is not a standard and well proven set up (at least not a widely published one) as in the case of hollow grinding - so there is some risk of unexpected issues arising.

My primary driver is that I have two sets of Japanese chisels in white steel. There's those that argue that they need the bevels ground flat to avoid the increased risk of breaking the hardened edge off that supposedly arises with hollow grinding, and those that argue that it's no problem whatsoever.

I guess I chose to take the conservative/safe route, and grind them flat. Having done so I really like the look and feel - and so have (somewhat pig headedly/against some very well intended advice) persisted in searching for a method of grinding that handles heavy metal removal entailed in re-angling bevels on wide baldes better than a disc sander. I'm also aware that for whatever reason it's traditional, and that there is a perhaps smaller but definite population out there that prefers for whatever reason to grind them flat.

My disc sander method was getting the job done, but tends to put a lot of heat in which slows metal removal right down. Which is a pain when e.g. re-angling plane irons. One alternative was to switch to a belt sander like the Sorby system, but the reports from yourself, David and others (and my own short trial) of the CBN wheels were so good (that they were doing such a remarkable job in terms of rapid metal removal for minimum heating) that it seemed a pity not to seek a way of using them. Especially since the cost is similar to the Sorby system, and it was proving tough to establish just how cool running it is.

Mike's posting of the availability of the WTW side/flat ginding wheels was the key enabler.

PS The fallback is that if for whatever reason it's not working out the same hardware (bench grinder + CBN wheels + Tormek accessories) can easily be set up for hollow bevel grinding...

Derek Cohen

11-07-2014, 9:35 PM

Ian, I have hollow ground my Japanese chisels for years now. Never experienced any issues at all. Neither has David Charlesworth, whose lead I followed. Another was Jim Krenov.

My only caution has been to avoid overheating the hard steel in the lamination. The 10" wet wheel of the Tormek never was an issue. I suspect - and will soon find out! - that the 8" wheel of the CBM wheel is also fine. After all, Krenov ground his Japanese chisels on even smaller wheels.

Test this out for yourself on a wider chisel first. Just go slowly ...

Regards from Perth

Derek

paul cottingham

11-07-2014, 11:09 PM

So here's a question. I am now grinding my blades with a 42" belt grinder. Is there any benefit to using a microbevel? As I see it, a microbevel basically is a way of not needing to waste energy regrinding the whole bevel every time. I realize it also may save some metal, but that is not as important to me.

bridger berdel

11-08-2014, 12:33 AM

When you say grind, do you mean that you follow the belt with honing on stones? If so, hone the microbevel. If you are using the belt as your final abrasive, don't bother.

So here's a question. I am now grinding my blades with a 42" belt grinder. Is there any benefit to using a microbevel? As I see it, a microbevel basically is a way of not needing to waste energy regrinding the whole bevel every time. I realize it also may save some metal, but that is not as important to me.

paul cottingham

11-08-2014, 12:56 AM

When you say grind, do you mean that you follow the belt with honing on stones? If so, hone the microbevel. If you are using the belt as your final abrasive, don't bother.
Yes, i should have been clearer. My final belt is around 2000 or so. I can strop as well.

ian maybury

11-08-2014, 7:57 AM

Thanks Derek. I knew you were hollow grinding your chisels, and working hard woods too - which is one reason why i know it's fine. Then there's the advantage when hand sharpening too - the solid lock in of the honing angle. All of which and more being reasons why I'm maintaining the option to fall back to doing so.

Don't mind my peculiarities in trying for an effective flat bevel grinding method, especially one also capable of removing lots of metal when needed - the intention is not to promote it as better or as a mainstream technique...

As a part of the above Paul I've been using a waterstone honed microbevel over a flat primary on plane blades. It's pretty incredible how quickly the honing goes in this situation (a hollow ground bevel would be similar) - just a few strokes are required on each stone to get an edge, and maybe only 10 or 12 on each side to add a moderate camber. Add the precision of a honing guide and work down to a very fine stone and the result (as i only recently discovered with help from especially David) is a spectacularly sharp, polished and flat but only about 0.5mm wide working micro bevel.

The single bevel sharpening i've been using on the Japanese chisels once an initial edge has been established while still quick takes a little longer. It's quick provided the set up (I'm using a dialled in Veritas Mk 2 honing guide) can return very accurately to the original bevel angle and blade alignment - even a slight misalignment makes it necessary to remove material over the entire area of the bevel which can be quite slow. The Mk 2 guide works well in this regard, but isn't perfect in that a tiny amount of misalignment can creep in on occasion.

One very big advantage of using a microbevel is that it's much less sensitive to variations in honing or grinding angles. It's got to make hand sharpening much easier than it would be done single bevel/Japanese style.

I've not tried fine belts, but if doing so would want to take care to avoid overheating (if the belt was running at a typical sander sort of speed - the Sorby ProEdge runs at about 700ft/min which is relatively slow). While it would be influenced a lot by the set up, another caution would be the risk of the belt not lying flat/of a ripple forming and running ahead of the tool - which if it happened might result in less than flat honing. Plenty of tension, and a flat platen underneath would seem advisable...

Mike Holbrook

11-08-2014, 8:57 AM

I think some of these issues are very much related to relative amounts. Hollow grinding that causes an extended very fine edge may be functional for straight razors that need to be very sharp but do not cut thick hard materials. Tools like straight razors are also hollow ground on both surfaces, making a much finer edge. I understand why this degree of hollow grinding will cause a problem on a chisel. Certainly the small amount of hollow grind Derek puts on a single side of his chisels is not the issue that deeper hollows may cause, especially double hollows.

For those who may not have Derek's penchant for invention:
Checking out the Tormek site I find the new BGM-100 Bench Grinder mounting set Derek mentions above. This kit offers all the hardware one needs to build a Tormek tool support/holding jig for 6-10" bench grinders, user supplies wood/material for base. The kit also contains a booklet with specific instructions on how to fit and adjust this jig to fit different size grinders. The kit includes a two piece height adjustable block that allows the user to set the tool bar at exactly the correct distance from the grinder wheel, both vertically and horizontally. The kit also contains rubber feet to be placed on a customized wood surface, supplied by the user, The rubber feet raise the bolts protruding through the wooden platform above the surface. The rubber feet may also dampen grinder/wheel vibration. The kit can also be mounted on a bench top. The kit contains profile labels, designed to be placed on the tool, which allow one to record the three settings necessary to replicate the profile/bevel in the future. Or we could use a Sharpie on the blade or handle.

Set up correctly using the Tormek Turning Tool Setter TTS-100, one can match settings on their Tormek tool rest to those on their bench grinder's Tormek BGM-100 tool rest. The user can then grind, even turning tools, on their grinder and hone on the Tormek without creating all those slightly off micro bevels.

David Weaver

11-08-2014, 9:21 AM

Ian, I have hollow ground my Japanese chisels for years now. Never experienced any issues at all. Neither has David Charlesworth, whose lead I followed.

I've done it from time to time with white steel chisels (the most temperature sensitive) and no problems, either. I only don't do it all the time because of a preference for seeing an attractive bevel on the chisels that I have.

Temper temperature for white steel is somewhere in the range of 275 degrees. Not much of any chisel I have ever gets that hot.

It'll be interesting to see how you guys get on doing it with CBN, which I wouldn't allow to get to the edge of very hard steel if I were grinding (because of the severity of the grooves cut), not because I think there will be a temperature issue but more if you notice whether or not the soft backer causes any issues (since all of the CBN wheels come with a specification to use them only on hard steel).

ian maybury

11-08-2014, 9:57 AM

There seeems to be some blurring on the issue of steel grade and CBN David. Some suggest that mild steel is OK, others that only hardened steel should be ground - and others that it's not a big deal since a touch with a hardened steel will clear any clogging caused by a softer steel. I did ask the question of one supplier about CBN on Japanese chisels, and the answer was no problem - but not of WTW. Hopefully it will prove OK, but mild steel sounds like its sailing close to the wind and these wheels are definitely not for general purpose use.

Build up on cutting edges when machining metal is a common problem. It usually happens when the metal is soft (e.g. a soft aluminium), and the rake angle (as in the pitch of a plane blade) is too steep. It's like it causes enough heating and pressure when the chip impacts the face of the tool to partially weld it to it, and to other chips. So chances are that the build up when grinding soft metals on CBN could be to do with the geometry of the cutting edges on the abrasive.

Agree from the trial earlier in the week that CBN definitely cuts deep grooves. Hopefully (again) if not the 80 the 180 grit wheel will get close enough to make for trouble free honing.

One confusing aspect of the whole situation seems to be that woodturners regard the edge that comes off 180 grit as sharp - they don't in general seem to go for polished cutting edges as we do on a plane for example… So its very possible that we could run into issues when honing...

Mel Fulks

11-08-2014, 10:02 AM

Is there a reduction in the grooves and roughness of the bevel with CBN if you move the chisel laterally? Seem to help when using the white wheels.

ian maybury

11-08-2014, 10:21 AM

It was only a fairly quick trial Mel, but looking at the blades manually ground earlier this week by slowly moving them on a tool rest across the (curved) face of the wheel the 180 grit is slightly lined, but getting close to a visually uniform satin finish. The surface left by the 80 grit (or maybe a bit coarser) wheel is quite deeply lined/grooved - more than enough to catch a thumb nail drawn across it….

Mike Holbrook

11-08-2014, 11:13 AM

Dave at D-Way told me that he felt soft metal could be cleaned off a CBN wheel simply by grinding a harder steel. Dave seemed to think just about anything could be ground on CBN wheels. Ken at WoodTurner's Wonders (WTW) said he felt softer steels could be a problem and grinding a harder steel might help but not be a totally reliable solution. I think Ken felt washing the wheel with soap and water might be an even better solution.

The reason I bought a 350 CBN was I felt from my discussion with Ken that it would smooth out the deeper grooves made by a 80 or 180 CBN. Ken offers a 220 CBN but that may be a little too close to a 180. I think Ken uses his 350 CBN for finishing lathe tools. I believe Dave told me he could not tell a difference in how his lathe tools worked coming off a 80 or 180 CBN, used right off the wheel. I believe both felt that grit changes on CBN wheels are not as significant as grit changes in many other stones.

ian maybury

11-08-2014, 7:54 PM

Just to convey what are probably the sort of tolerances typical of Eastern made bench grinders - I measured up my recently bought fairly generic 8in low speed UK originating example (i think the cheaper model that Derek mentioned first trying in Australia) tonight to see how it might do with CBN wheels on. It was picked as the smoothest out of a batch, and while not tightly toleranced by the standards of a good electric motor turns out not to be too bad. It runs smoothly with the grinding wheels off.

Unlike many US grinders which have a 5/8in nominal (solid) shaft it's a nominal 18mm dia in this case - so the WTW CBN wheels which have a nominal 5/8in bore (just under 16mm) will require re-boring.

The shafts measure from about 17.92mm to 17.97mm dia depending on the end and where measured. Very similar to stock grade bright mild steel shafting, but a fairly loose tolerance by motor shaft standards. To provide something to compare it with - changing the clearance (measured as diameter difference) from 0.029mm to 0.035mm takes the fit of an 18mm dia shaft in a bore from about as tight as is possible while still having a sliding fit, to a slightly less snug but still well located slding fit.

Runout is OK, about 0.025mm (0.001in) one end, and 0.05mm (0.002 in) the other - which is about at the upper end of what's permitted by the IEC standard on a standard quality electric motor.

The motor shaft is offset a little to one side of the grinder - so that the step on the motor shaft that locates the stepped sleeve that mounts the wheels is inside the line of the end face of the housing on one end by about 1mm, and proud of it at the other by about 2.5mm. i.e. a stepped sleeve is needed to clear the motor housing.

What's not so good is the fit of this stepped sleeve - the bore is about 18.1mm, meaning there is potentially plenty of slop to throw the balance out. The stock grinding wheels in turn seem a pretty appoximate fit over these sleeves, but were not measured.

Depending on how the tolerances add up after assembly, a given example running stock wheels could be moderately smooth running, or quite rough.

It seems though that the CBN wheels when bored accurately to fit directly on the shafts will probably run very close to true. A pair of self aligning washers and some ground (hardened and flat) shim washers will also be required too to set up the spacing since there's about 50mm (2in) of shaft length available each side for a wheel width of 32mm ...

Chris Fournier

11-09-2014, 12:02 PM

Hi Ian

I am still trying to work out what advantage you find with a flat ground primary bevel over a hollow ground primary bevel. Why? It certainly complicates matters - possibly unnecessarily.

Regards from Perth

Derek

Absolutely agreed. If you are sharpening your tools because you are working wood, then sharpening is ancillary to the woodworking. I want fast and effective sharpening so that I can stay "in" the project. A hollow grind fits this bill. I have yet to ruin one tool regardless of construction by using a hollow grind. The hollow grind allows me to register the bevel to the stone by feel in a moment, a few careful strokes and back to the woodworking. Reduces "stiction" too I should add.

Reinis Kanders

11-09-2014, 12:54 PM

Do you guys hollow grind to the final bevel angle or do you hollow grind to 25 degrees and then lift the handle for subsequent honing at the workbench?

dan sherman

11-09-2014, 1:06 PM

Absolutely agreed. If you are sharpening your tools because you are working wood, then sharpening is ancillary to the woodworking. I want fast and effective sharpening so that I can stay "in" the project. A hollow grind fits this bill. I have yet to ruin one tool regardless of construction by using a hollow grind. The hollow grind allows me to register the bevel to the stone by feel in a moment, a few careful strokes and back to the woodworking. Reduces "stiction" too I should add.

just because you haven't had a problem with it doesn't mean it hasn't happened to other people.

David Weaver

11-09-2014, 1:20 PM

Do you guys hollow grind to the final bevel angle or do you hollow grind to 25 degrees and then lift the handle for subsequent honing at the workbench?

The latter, but either way works. It takes less effort to hone using the second method, or honing the flats with a coarser stone and then lifting the handle a little for the fine stone.

I've always found a much higher low-effort hit rate with the edges lifting the last stone a little, and using a very fine or slow stone for that part of the edge-making as it removes less metal and leaves you better set up for the next go around.

bridger berdel

11-09-2014, 4:27 PM

Do you guys hollow grind to the final bevel angle or do you hollow grind to 25 degrees and then lift the handle for subsequent honing at the workbench?

I don't always do it the same way.

for very low angle tools I use what approaches a flat bevel with just a little bit of a microbevel.
for thick tools with a high angle, I'll generally hollow grind and follow with a honed microbevel.
for a lot of the stuff in between it is similar to what Paul Sellers advocates: a convex bevel that pretty much includes the microbevel. but when it starts getting too rounded I go ahead and give it a bit of a hollow grind to get some of that metal out of the way. I freehand grind, so I'm not stuck with a hollow grind at the radius of the grinding wheel. it's easy enough to work the chisel around on the stone to produce a hollow grind that is really close to flat, and after a few times at the stones it ends up slightly convex. but I don't obsess over the shape of my primary bevels. as long as the edge is as sharp as I need it to be and is as straight or curved as I need it to be I'm happy.

Chris Fournier

11-09-2014, 6:33 PM

just because you haven't had a problem with it doesn't mean it hasn't happened to other people.

I'm not sure exactly what your point is Dan? I know that other people are having troubles.

My point is that you don't have to have a problem. If someone is hollow grinding and ruining their tools in use then I think that the problem is operator error and that can be fixed with study of the basics and practice. Watch your bevel angle, matching it to the task at hand, and hollow grind to your hearts content, there need not be a problem. I am not a magician, just a woodworker who has applied principles and practices laid out by those that came before me and I have earned the skills with time on the tools and patience accepting that failure is always a possibility.

Personally I think that a lot of what we discuss around here comes down to folks who watch a you tube video or a blog, try it a couple of times themselves and then throw up their hands in disgust or dispair when they don't get perfect results inside of 30 minutes. Perseverance in this instant gratification age is a quality that most of us are lacking. It keeps these forums humming.

dan sherman

11-10-2014, 9:42 AM

I'm not sure exactly what your point is Dan? I know that other people are having troubles.

My point is that you don't have to have a problem. If someone is hollow grinding and ruining their tools in use then I think that the problem is operator error and that can be fixed with study of the basics and practice. Watch your bevel angle, matching it to the task at hand, and hollow grind to your hearts content, there need not be a problem. I am not a magician, just a woodworker who has applied principles and practices laid out by those that came before me and I have earned the skills with time on the tools and patience accepting that failure is always a possibility.

I was responding to your comment on hollow grinding regardless of construction. I don't mean to single you out, your post just triggered something i think needs to be said.

The creek has lost some objectivity in my opinion, and fallen into what I would call "do what we do because it works for us" mentality. It seems, gone are the days when people discussed the caveats of why one method might be better or more appropriate than another.

for example:

Japanese chisels, can be hollow ground, but several caveats should be considered before doing so.

1. is the chisel laminated? not all of them are, traditional woodworker for example sells solid hss versions.
2. what type of steel is it made from white steel, blue steel, other? White is more brittle and temperature sensitive than blue.
3. how will the chisel be used and what angle will it be ground to.
4. what diameter wheel is it being ground on? a 6" wheel produces a much less supported edge than a 10" wheel for a given bevel angle.

So, while someone might not have any problems taking paring cuts with a blue steel chisel hollow ground to 35 degrees on a 10" wheel, a person making light mallet cuts with a white steel chisel ground to 30 degrees on a 6" wheel could have all kinds of problems.

I guess i just wish people espoused understanding the details/cavets over general rules of thumbs.

ian maybury

11-19-2014, 3:16 PM

Guess as is often the said 'the devil is in the detail'. Or more to the point - only your specific case is your reality. Rules by definition are standardised one size fits all procedures...

This post is actually just to say that my 80 and 180 grit CBN wheels have arrived from WoodTurnersWonders, and to offer some thought on boring them to suit the grinder shaft size.

The stock 5/8in bore on the WTW wheels requires opening up to the 18mm nominal of the (UK market) grinder shaft in my case. (actually a shade under - measure each shaft end in several places with a micrometer before deciding on the required bore size - roughly 0.001 - 0.0015 in clearance -diameter difference- should deliver a precisely located sliding fit at this shaft size) Some of the other CBN wheel makers bore their wheels oversize, and offer reducing sleeves to suit common US shaft sizes. I'm planning to bore both wheels to the same diameter to suit the smaller end of the grinder shaft (both ends are not quite the same diameter on my grinder), and to adjust the fit by reducing the diameter of the larger end using emery cloth - so that either wheel can go on either shaft end/side.

It's maybe worth putting up a few thoughts on boring wheels like these - feel free to add views/options. On the basis that there's potentially a few pitfalls in getting the job done right. It's important that both wheels end up running true - both in terms of runout, and of side to side wobble. (the WTW wheels grind off their side faces as well as the periphery to do flat bevels as well as the hollow ground variety, and are 6061 aluminium)

The simple way would be to try it under a drill press, but unless everything is very well set up indeed there's for me an unacceptably high risk of the bore ending up misaligned - plus unless a machine reamer is used after an undersized drill there will likely be problems in achieving a correctly sized hole too.

One method is to use a small boring bar on an accurate engineer's lathe - making sure to check for wobble and runout first (that the wheel is accurately centred, and chucked square) using a dial gauge in both directions. (soft jaws bored to suit in a 3 jaw chuck are a good way to get concentric) Hitting the diameter with the boring bar and setting the chuck requires a skilled machinist, but has the advantage that it by definition finds the true centre of rotation.

It's easier to bore in the lathe using a Morse taper drill and then a machine reamer off the tailstock (and it's certainly the simplest way to accurately hit a given diameter), but there's a risk of inaccuracy if the tailstock is not accurately set up/aligned or a floating tool holder is not used. Which isn't always the case on lathes in less precision oriented machine shops, or on older/worn machines.

The other task is to dig up four sets of 18mm + bore self aligning/spherical washers (M16?) to go at each side of both wheels. This reduces the risk that a less than perfectly square cut thread or shoulder on the shaft will tip the wheel out of alignment when the retaining nut is done up....

dan sherman

11-19-2014, 3:28 PM

The simple way would be to try it under a drill press, but unless everything is very well set up indeed there's for me an unacceptably high risk of the bore ending up misaligned - plus unless a machine reamer is used after an undersized drill there will likely be problems in achieving a correctly sized hole too.

A potentially more reliable method is to use a boring bar on a lathe - making sure to check for wobble and runout first (that the wheel is accurately centred, and chucked square) using a dial gauge in both directions. The boring bar requires a skilled machinist to hit the required diameter within the required 0.001in or so tolerance, but has the advantage that it by definition finds the centre of rotation.

It's easier to bore in the lathe using a drill and then a machine reamer off the tailstock (certainly the simplest way to accurately hit a given diameter), but there's some risk of inaccuracy creeping in if the tailstock is not accurately set up/aligned. Which isn't always the case on lathes in less precision oriented machine shops, or with older machines.

I'd recommend chucking it up in a 4 jaw on the lathe and getting it running true. Then Drill, bore, and finally ream. The drill removes the bulk of the material, the Boring bar insures the hole is true, and the reamer ensures accurate size.

David Weaver

11-19-2014, 4:56 PM

Guess as is often the said 'the devil is in the detail'. Or more to the point - only your specific case is your reality. Rules by definition are standardised one size fits all procedures...

This post is actually just to say that my 80 and 180 grit CBN wheels have arrived from WoodTurnersWonders, and to offer some thought on boring them to suit the grinder shaft size.

The stock 5/8in bore on the WTW wheels requires opening up to the 18mm nominal of the (UK market) grinder shaft in my case. (actually a shade under - measure each shaft end in several places with a micrometer before deciding on the required bore size - roughly 0.001 - 0.0015 in clearance -diameter difference- should deliver a precisely located sliding fit at this shaft size) Some of the other CBN wheel makers bore their wheels oversize, and offer reducing sleeves to suit common US shaft sizes. I'm planning to bore both wheels to the same diameter to suit the smaller end of the grinder shaft (both ends are not quite the same diameter on my grinder), and to adjust the fit by reducing the diameter of the larger end using emery cloth - so that either wheel can go on either shaft end/side.

It's maybe worth putting up a few thoughts on boring wheels like these - feel free to add views/options. On the basis that there's potentially a few pitfalls in getting the job done right. It's important that both wheels end up running true - both in terms of runout, and of side to side wobble. (the WTW wheels grind off their side faces as well as the periphery to do flat bevels as well as the hollow ground variety, and are 6061 aluminium)

The simple way would be to try it under a drill press, but unless everything is very well set up indeed there's for me an unacceptably high risk of the bore ending up misaligned - plus unless a machine reamer is used after an undersized drill there will likely be problems in achieving a correctly sized hole too.

One method is to use a small boring bar on an accurate engineer's lathe - making sure to check for wobble and runout first (that the wheel is accurately centred, and chucked square) using a dial gauge in both directions. Hitting the diameter with the boring bar and setting the chuck requires a very skilled machinist, but has the advantage that it by definition finds the true centre of rotation.

It's easier to bore in the lathe using a Morse taper drill and then a machine reamer off the tailstock (and it's certainly the simplest way to accurately hit a given diameter), but there's a risk of inaccuracy if the tailstock is not accurately set up/aligned. Which isn't always the case on lathes in less precision oriented machine shops, or on older/worn machines.

The other task is to dig up four sets of 18mm + bore self aligning/spherical washers (M16?) to go at each side of both wheels. This reduces the risk that a less than perfectly square cut thread or shoulder on the shaft will tip the wheel out of alignment when the retaining nut is done up....

Are there any small machine shops near you? I'd imagine that since the core of the wheel is aluminum, they could chuck it and drill and ream it pretty easily. I agree that a drill press is a no-no since there is no such thing as truing it again once it's on the wheel. You wouldn't like the wheel if you only had a small contact patch touching the tool.

Steve Voigt

11-19-2014, 6:24 PM

This thread is absolutely mind boggling to me. Spending hundreds of dollars for cbn wheels, and then they need to be modified at a machine shop before they can even be used? And hundreds more spent, no doubt, on tool rests and other paraphernalia. All to accomplish a mundane task that can be done with cheap, off-the-shelf equipment. It's like the woodworking equivalent of a hair shirt.

People can do whatever they want, and spend their money however they want, and it's no skin off my nose. But I worry about about the newbies who come to this site looking for advice. I hope to high heaven none of them are seriously thinking about going down this road. To them I would say: ignore almost everything you've read in this thread. Get a modestly priced 6" grinder and use the stock wheels, or get some $40 friable wheels if you really want to live it up. And then, spend your free time learning how to use it. I submit that would be a more productive use of time than endless hours of forum posting and internet "research" trying to find some skill-free technology that will solve all your problems.

paul cottingham

11-19-2014, 6:38 PM

Yeah, but isn't that one of the points of a place like this? A forum where people can discuss methods of work, that go beyond the basics? I personally have trouble grinding on a wheel, no matter how much I practice. I doubt I'm alone.

ian maybury

11-19-2014, 8:06 PM

Nobody is claiming that CBN is the way to go for all Steve - although if the wheels last almost indefinitely as has been claimed, don't throw grit everywhere, and meanwhile don't wear/change dimensions then longer term in 6in form they may not be such bad value or such an indulgence at $149 a pop: http://woodturnerswonders.com/products/copy-of-copy-of-cbn-wheel-220-grit-6-inch These prices are already dropping, and seem likely with wider adoption to drop further.

The thread though isn't about setting up basic bevel grinding capability, or even just about re-grinding existing bevels. As before it's 100% clear that hollow grinding on a stock bench grinder is a cheap and very cost effective route to this - one that combines many advantages.

It's about trying out some possibilities, and sharing some experience. Which for some of us happens to be a fun activity that draws on other aspects of our backgrounds. But which may not work out.

There's been a few cross purposes, but the thread has from the start been about seeking a set up that can handle jobs from re-grinding to remove a honing bevel right up to the heavy work of putting a new bevel on a blade blank, or re-angling a bevel - all to a high level of accuracy and a good finish, and with speed and minimal risk of overheating. With in this case the ability to be set up to grind flat bevels, or to hollow grind - with the aim for the moment of enabling single bevel sharpening and subsequent honing with a guide.

The boring of the wheels is relatively easy in my own case (David), it's a matter of getting an hour on a friend's lathe. They come in 5/8in bore as stock, which fits many US grinders anyway.

It meanwhile seemed worth posting the piece on boring wheels - to help reduce the possibility of anybody that did find themselves needing to bore wheels (or indeed anything else similar) running into trouble...

Steve Friedman

11-19-2014, 9:02 PM

Thanks Ian,

That was well put. I agree that when it comes to sharpening many of us go way beyond what most may consider reasonable. Even David, who now uses one stone, has probably tried more stones than any of us will see in out lifetimes. If I was trying to make a living as a woodworker, my viewpoint may be different. But, as a hobbiest, part of the fun is trying out different ways of doing things, even though much of it may not be the financially astute thing to do.

Steve

Mike Holbrook

11-19-2014, 10:11 PM

I don't find the information in this thread to be overboard in terms of cost or time spent. Like Ian says the price of CBN wheels is going down and if one compares the cost on a CBN wheel or two to stone wheels I don't think the costs are far appart. If one factors in that one CBN wheel will probably outlast several friable wheels without a change in wheel size going on all the time. The cost of CBN wheels and even "the best" tool rests is small potatoes compared to what many have spent on water stones, particularly the very fine ones. A Tormek or Veritas MKII grinder is more. A good grinder is more. Baldors can cost several times more. A Worksharp with the extras and papers for a year is comparable or more.....Take all the funds a guy like David may have spent exploring a host of sharpening options and it is still a drop in the bucket compared to what many power tool guys spend for machines. The much higher safety factor with CBN wheels vs friable stone wheels is invaluable to me.

The key issue in my book is time. A hand tool woodworker with 4-6 planes 6-10 chisels, hand saws....has quite a few cutting surfaces to maintain. Many of us have far more edged tools. Enjoyment and success with hand tools seems to me to revolve around ones ability to maintain sharp cutting surfaces. We don't just buy new blades for power tools, replace the old ones and power back up. Sharpening is the constant in using hand tools that we can not escape. How to speed up the process of sharpening is eminently relevant to using hand tools. I don't know what could be more relevant. Someone may say just working wood is more important. It may be, but no one gets squat done with dull tools. CBN wheels and good tool rests are relevant because they may be the quickest way to accurate repeatable sharpening of hand tools.