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Derek Cohen
03-05-2015, 1:29 AM
A short while ago I posted a warning about purchasing the radiused CBN wheels for grinding flat blades (bench planes and bench chisels) as I had been experiencing difficulties obtaining a straight grind. I posted this as I felt a responsibility having written such glowing praise about the CBN wheels I built into a grinding centre.

It is relevant to note that the CBN wheel have been around a long time (several years at least) and have a superb reputation among turners. They were, however, little know among flat woodworkers .... mainly because they offer the capability of grinding the steels that are more commonly used by turners than flat woodworkers (such as HSS). In other words, they were designed with turners in mind.

The performance of the 180 grit wheel I purchased from D-Way absolutely blew me away, and I wanted to share this with all that they could also work on flat blades.

There are different shape CBN wheels available. I purchased ones with a radius as I was impressed with their potential for lathe chisels, which I also use. There are also available straight wheels (similar to standard grinder wheels). In retrospect, that is what I should have bought instead.

There is nothing wrong with the radiused wheels for grinding lathe chisels. They are perfect for that purpose. However, they are not designed for flat grinding of plane blades, where the wheel area is narrower than the plane blade. A straight wheel would be better suited for this purpose.

I am still 100% behind the CBN wheel. They have that much potential in my opinion. So much so, I am am replacing the radius wheels with straight wheels.

The service and backup I have had from Dave at D-Way has been superb. Not only has he answered my emails, but we discussed the nature of the set up I have by telephone.

Regards from Perth

Derek

Matthew N. Masail
03-05-2015, 2:15 AM
Derek I very much appreciate this.
It is still not clear - is the slight concave center is purposeful for rounded turning tools, a different manufacture tolerance between the wheel shapes, simply a by product of the rounded corners... ?

Derek Cohen
03-05-2015, 2:26 AM
Hi Matthew

Some have reported a slight concave, like mine, and others have not found this. I don't know what to conclude. I have had a report from the factory to say that the section between the radii is ground flat. The radii are ground after the faces are ground flat, and it could be that on some wheels this pushes the steel up a little - I am hypothesising here. Please do not take this as fact. The point is, however, that the radiused wheels are fine for turners and that the straight wheels are probably better suited to flat woodworkers. I trust this assumption enough to get two replacement wheels, both straight.

Regards from Perth

Derek

Kees Heiden
03-05-2015, 3:04 AM
Thanks for the update Derek. This puts me off the fence again. i would really like a radiused edge for things like moulding plane irons and stuff like that.

Matthew N. Masail
03-05-2015, 7:54 AM
Hi Matthew

Some have reported a slight concave, like mine, and others have not found this. I don't know what to conclude. I have had a report from the factory to say that the section between the radii is ground flat. The radii are ground after the faces are ground flat, and it could be that on some wheels this pushes the steel up a little - I am hypothesising here. Please do not take this as fact. The point is, however, that the radiused wheels are fine for turners and that the straight wheels are probably better suited to flat woodworkers. I trust this assumption enough to get two replacement wheels, both straight.

Regards from Perth

Derek

I also thought that the grinding of the rounded corners might be what causes the aluminium to bent slightly, as aluminium is know the twist when welded and such. I truly hope you are right with your assumption that the flat version will indeed be flat, because that is a lot of money to spend for a not perfect grinding wheel. do you know if they offer any guarantee for flatness? I would hesitate to spent over 200$ to get one over here once my white wheel is used up if they do not offer any guarantee.

Tom M King
03-05-2015, 8:18 AM
I'll repeat what I said on the other thread. My 180 grit radiused edge wheel from D-way is still dead flat, where it should be, after 15 months use. If I go back over there today, I'll get a picture. Just based on the differences between Derek's and my results with the same wheel from the same place, I don't think the dishing problem is simply a result of the radiused edges.

Pat Barry
03-05-2015, 8:24 AM
There is nothing wrong with the radiused wheels for grinding lathe chisels. They are perfect for that purpose. However, they are not designed for flat grinding of plane blades, where the wheel area is narrower than the plane blade. A straight wheel would be better suited for this purpose.
Hey Derek, Its interesting that the corner radius is creating problems for you with regard to grinding the blades. In most cases, the blade is wider than the wheel. You need to move the blade across the wheel uniformly to get a straight edge. I don't see why having a radius on the corner of the wheel would change that, in fact, I was thinking the corner radius would actually be beneficial to easing the blade across the wheel and not having the propensity to dig in on a corner. Much like the reason you might round over the corners on your plane blade, to keep the corner edges from digging in. I would be interested in more of your reasoning for advocating the straight wheel vs the radiused wheel

Derek Cohen
03-05-2015, 8:36 AM
Hi Pat

What needs to be recalled is that my grinding set up uses the Tormek BGM-100 tool rests. These move the blade in a line parallel with the tool rest. If the wheel has hills and valleys, and the blade runs along this, the blade will end up with an irregular edge. This does not apply if one free hands the blade, as I mentioned in my previous report. In fact, a curved wheel face is recommended by Joel Moskowitz in his FWW article, and it is what I used when freehanding on a white Norton wheel. If one uses the BGM-100, however, the wheel face needs to be flat and straight - as the Tormek wheel is required to be flat and straight when grinding a blade.

Regards from Perth

Derek

Mike Holbrook
03-05-2015, 9:16 AM
I have two CBN wheels a 180 from D-Way and a 220 from WoodTurners Wonders. I have not used either wheel heavily but have reground bevels on both. To date both wheels look flush across the top, using my engineers square to visually check them.

I do find that the fine wheel tends to heat up faster. I still use it and the heat created has not caused a problem but the difference is noticeable.

I have two tool rests: 1) the typical LV rest with the sliding blade holder 2) Stuart Batty rest from Woodworker's Emporium (the curved sided rest)

Mike Holbrook
03-05-2015, 11:23 AM
Derek I am wondering if deflection of the Tormek tool holding bar could in some way be contributing to the issue you are finding? I used different tool rests on my CBN wheels because it seemed to me that when applying the higher pressure to grind a radius/bevel in a wide plane blade on my wide Tormek wheel I might have been deflecting my BGM-100 tool bar enough to cause an issue. I should probably mention that I have an old Tormek and the older rest jigs. I believe Derek and David did some strenuous testing soon after getting their wheels in order to determine how much heat these wheels produced in hard use, which might be the variable producing a different result in Derek's case. In my experience finer abrasives can cause more heat and I believe Derek's wheel had a finer abrasive than David's.

Another possible issue could be the wheel not turning precisely on the arbor. I am having a hard time figuring out if my wheels are rotating properly. I believe both CBN wheel "manufacturers" I dealt with mentioned this issue and methods of preventing it. My understanding was that some of the arbors that come on grinders may not be perfect or retain burrs from manufacturing...I bought a washer set from WoodTurners Wonders (I think). The washers are suppose to help dial out wobble by rotating them in opposite directions. So far, I am having trouble figuring out how to tell when/if I am improving the wheels wobble. I am no geometry/physics whiz but I think these much wider/hollowed/heavy wheels compound any wobble/pressure/heat issues vs smaller solid "stone" wheels. Tormek uses an even wider wheel, but they rotate it at a much slower speed.

Another thing I wonder about is the alloy used to make these wheels. I think the last wheel I bought is aluminum. I suspect "other" wheels may contain aluminum or other metals that might deflect under heat and pressure. I know the weight of these wheels can be hard on some grinders and the manufacturers apparently are experimenting with alloys, wheel sizes etc. to deal with all the weight. Until a sizable manufacturer, aka Lee Valley, decides to invest a sizable amount of time & money in research we may be feeling our way in the dark. I am also thinking about calling someone who forges woodworking tools, Barr Tools maybe, to see if they can offer any insight into heat and pressure with these types of metals. Maybe one of our posters can help?

I am just trying not to do too much grinding too fast on my wheels until I am comfortable with weight/heat/wobble factors and how they may or may not affect: my wheels, my grinder and the tools being ground.

Derek Cohen
03-05-2015, 11:42 AM
Hi Mike

The Tormek tool rest is quite substantial and very difficult to deflect. It occurred to me and I tried to make it do so. It would not. Using the tool rest on the Tormek is different to using it on the CBN wheel. On the Tormek one tends to use a great deal of downforce (I do), but the CBN wheel only requires a very light touch. So where would the defection come from?

Keep in mind that my initial experience with the 180 grit CBN wheel was very positive, with a perfectly straight grind. So what happened? I bumped the set up and through it out. I could never get it back again. I suspect that I got lucky the first time by working on a sight angle - I was using the set up directly from the white wheels that the CBN replaced. The problems began when I tried to set it up square.

Again, it is possible to freehand on this CBN more successfully than when using the BGM-100 tool rest.

Regards from Perth

Derek

Tom M King
03-05-2015, 11:50 AM
I use the Veritas grinding stand, and guide most of the time, so I don't think the stand is the issue. The Veritas stand is very rigid as well. The other difference I noted is that I only use O1 tools. I wonder if the harder steel tools make a difference in wear. At this point, there is not enough evidence to say exactly what caused the problem, if it existed to start with, or if it presented after an amount of use. I'm sure I've used mine way more than any hobbyist woodworker would use one in a year, but again only with soft steel tools.

Steve Voigt
03-05-2015, 1:02 PM
Derek,

Just wondering if this experience will affect the way you go about recommending tools and gear in the future. I imagine a fair number of people went out and bought a radiused wheel and a Tormek guide based on your (very enthusiastic) recommendation. If they now buy a flat wheel, they are in for close to 400 bucks. That's more than I would spend on grinding gear in a couple lifetimes. When this subject came up a few months ago, I got a fair amount of grief from a number of people for expressing skepticism about these wheels, but I think skepticism was warranted.

Perhaps it would be a good idea to wait 6 months or so before issuing endorsements, to see if the items pass at least a minimal test of durability. I know I have certainly purchased tools and been very enthusiastic about them initially, only to be disappointed later.

On the specific topic of CBN wheels, I'll paraphrase what I said in earlier threads. A traditional grey or white wheel, or Norton 3X, can be ground to any profile you want. That flexibility is very useful, and it also means you're not at the mercy of the manufacturer's standards for flat, straight, or perpendicular. The cutting surface can be renewed almost indefinitely, whereas the durability of cbn wheels still seems to be an unknown quantity. And even the relatively expensive white or 3X wheels are a quarter of the price of the cbn wheels.

Steve Voigt
03-05-2015, 1:05 PM
Thanks for the update Derek. This puts me off the fence again. i would really like a radiused edge for things like moulding plane irons and stuff like that.

Just get a soft wheel. You can dress it to whatever radius you want.

Kees Heiden
03-05-2015, 3:48 PM
Yes that's what I do now with a 3X wheel. It's a messy wheel though, creating a lot of dust. I hoped the CBN wheel would be an answer to that, but I understand your concern too.

Steve Voigt
03-05-2015, 4:50 PM
Yes that's what I do now with a 3X wheel. It's a messy wheel though, creating a lot of dust. I hoped the CBN wheel would be an answer to that, but I understand your concern too.
Yeah, the 3X wheels are still pretty hard. I think most people use the softer white wheels for profiling--not necessarily less dust, but faster and easier to profile. The 3X are great for more general grinding, though.

ian maybury
03-05-2015, 5:19 PM
I guess that if the work is guided/supported in 3D as it tracks in a straight line across a wheel then a little irregularity may be no problem, but if it's relying on the wheel for support then it may well be.

Don't know enough to have a clue what the situation might be here, but CBN wheels are used all over industry for very high precision grinding tasks. e.g. http://www.reishauer.com/en/CBN-profile-grinding-wheel-103.html A specific enquiry made when buying my wheels (which are of a different brand) resulted in an assurance that they were accurate to within a small part of a thou. So far as i can tell before use they check out fine.

It doesn't seem all that likely that this is a fundamental flaw/anything to do with the nature of the beast - more that if there are instances of issues that it's a quality problem. To do with the manufacture of the specific wheel, or a batch or some examples of them. The sort of thing the original manufacturer might be expected to stand over?

Tom M King
03-05-2015, 6:06 PM
My feelings as well Ian, that it was probably some manufacturing error, but not a universal one, since my CBN wheel is fine. I'm still loving mine, and won't ever go back to anything else. I expect mine has already paid for itself in hours not spent doing other, slow grinding.

Derek Cohen
03-05-2015, 6:54 PM
Ian, my thought is that there are a few rogue wheels - just like any tool - and I had one (actually two, both radius wheels from different sellers). In both cases, the back up service has been superb, and one should have no fears purchasing one of these wheels in case of a dud.

Steve, I agree that one needs to be careful when recommending any tool and that there is a high level of reliability included, which is generally something that occurs with re-testing over time. If I report something enthusiastically, as I did, I take responsibility if turns out faulty. I had looked into the history of the wheels beforehand, and in this respect the information about the product was not premature. I do not know the answer here - one of my conclusions must be that my report was too soon, however.

As mentioned before, the CBN technology is the future. I have no doubt. The question is whether the accuracy level is there for guided tool rests, such as the BGM-100, not whether they work. I am confident enough that the technology is indeed here, and will report back later on the new wheels.

Regards from Perth

Derek

Derek Cohen
03-07-2015, 8:57 AM
One more piece for the follow up file ...


Dave at D-Way returned my payment for the wheel, which I then sent back to him. I plan to keep and use the 180 grit radiused wheel for lathe chisels. It may not be suitable for bench chisels but it will be fine for the lathe. I plan to hook it up to a grinder alongside the lathe.


In the meantime, the 180 grit 1 1/2" wide straight CBN wheel arrived from my Oz supplier. It is nicer than I imagined, with a wide, flat section on the side that may be useful for flattening the backs of blades. The 80 grit wheel is on its way back to the US supplier, who will exchange it for a straight wheel. He has been just superb in his service.


I have set up the new CBN wheel and and I think that we are back in business. So far the grinds are straight. Time to let it settle in. Feedback at a later date.


http://i13.photobucket.com/albums/a262/Derek50/CBN-flat2_zpsyleve1mf.jpg


Regards from Perth


Derek

Tom M King
03-07-2015, 9:46 AM
I really like the looks of that wheel. I've been waiting for the right thing to go on the other end of my grinder that I have the one CBN wheel on-just wish that one wasn't on the upside down part of the globe. Looks like when you turn that grinder off today, that it will still be spinning tomorrow.

Jack Vines
03-07-2015, 11:40 AM
I was asking a machinist friend about CBN wheels and showed him this thread. He read it and said,

"Doesn't anyone there see the irony in using power grinders with CBN wheels and expensive tool holding jigs for sharpening hand tools in a forum called "Neanderthal Heaven?"

jack vines

Brian Holcombe
03-07-2015, 1:00 PM
We're very well kept neanderthals.

Reinis Kanders
03-07-2015, 1:01 PM
That looks like the one wheel to rule all wheels:) How heavy is it?

Derek Cohen
03-07-2015, 7:50 PM
Reinis, you wouln't believe how heavy! The 80 grit wheel I shipped back was a feather by comparison (and my shipping cost to the USA was $62 AUD). I have not weighed the new wheel, but the package was Heavy! So at least twice the weight of the other.

I have no doubt at the new wheel is available in the States. There are not a lot of manufacturers for CBN wheels. Use this photo and ask around.

Regards from Perth

Derek

Reinis Kanders
03-07-2015, 9:11 PM
Thanks Derek. I have a wheel envy now:)
I might get a wider wheel for my grinders other side, but I will wait for a bit and see how it plays out with my current wheel. So far it has been great and I appreciate that you started the CBN wheel movement on this forum. I don't do any turning yet and had no idea that such a nice solution exists.

Chris Parks
03-14-2015, 5:07 AM
Derek, where did you get that wheel from, CWS?

Derek Cohen
03-14-2015, 10:44 AM
Hi Chris

Yes ... http://www.cwsonline.com.au/shop/category/woodcut-cbn-grinding-wheels

Jim Carroll is the guy to work with.

Regards from Perth

Derek

ian maybury
03-14-2015, 1:53 PM
Think that ideology has no place in woodworking - whether or not it's hand tool based...

The new wheel looks the business Derek - spot on for flat bevel grinding off the side too.

To be fair to D Way it sounds like he's very much standing over the product, and that whatever problem is likely to be restricted to a batch.

There's however another issue in the CBN wheel situation that has the potential to be troublesome when grinding tools requiring accurately flat bevels.

The machining of the spindle on your average Eastern made grinder isn't necessarily a high precision deal. It's not just about straightness and concentricity, it's also about how square the step the wheel is tightened against is, and how squarely the threads on the end of the shaft and in the nut have been cut. The relatively small diameters used on most grinders and the soft steel mean they have very little resistance to bending.

The point here is that spindle precision not so important in the case of friable stone that's dressed in the traditional manner - because the dressing will likely ensure that it ends up being cut to run fairly true. A CBN wheel doesn't have this 'adjustability'.

The shafts on my own grinder clock with a dial gauge as running pretty true, but one end when the securing nut is tightened up develops a bit of a wobble. Most of which (subject to final checking) seems to have been eliminated by fitting the previously mentioned spherical washers like those offered by WTW.

Presuming reasonable manufacturing significant eccentricity is not so likely, but some side to side wobble is a definite possibility. Unlikely to be avoided in fact. There's also the matter of how precisely the wheels are bored, and how that adds to or compensates in the mix.

How some mix of slight eccentricity and sideways wobble might work out in terms of the straightness of the bevel grind and uneven wear is potentially a bit unpredictable - it'll make a difference whether the iron pivots forward on to and is supported by the wheel a la Tormek jig, or whether the jig locates the iron firmly in all axes as in the case of say the Lee Valley jig. It needs some calculation to figure out how much out flatness inaccuracies in the various directions may induce for both types of jig.

The good news i guess is that we're grinding primary bevels here, so there is presumably some tolerance for a less than perfectly flat bevel - especially if the subsequent honing is micro bevel over hollow grind based. Less so if the target is a flat bevel Japanese chisel style - but it will still be OK if the bevel pretty quickly cleans up all over on say a 1,000 grit waterstone. Or even using a honing guide on the top disc on a WorkSharp if you have one - the real benefit of the CBN wheel for me is for low heat heavy rates of metal removal when e.g. changing the primary bevel angle on a thick iron.

It'd be interesting if you were to clock your latest wheel set up with a dial gauge on a stand (running a gauge on an abrasive surface isn't ideal, but still...) and see what eccentricity and side to side wobble you are getting with everything done up tight, as it'd provide some context for what you experience in terms of grinding results. Depending on the nature of any issue there might be scope to do a little dialling in too.....

ian

Tom M King
03-14-2015, 2:26 PM
I ordered one new grinder when I first got the D-way radiused edge fine wheel. I sent that one back and tried another brand. The Metabo runs dead true. My D-way wheel was flat when I bought it, and after grinding a years worth of stuff on it, it's still nice and flat on the flats. I wouldn't have any reservations about getting another one of these wheels. Get a grinder from cpo, and wheel from D-way, and if it doesn't work out, they send a pickup label, and charges are taken off your card. cpo picked up the Dewalt grinder, and shipped me the Metabo. The Metabo does require a bushing for proper offset, but runs dead true. This setup has already paid for itself in time saved for me, if I had to buy another one tomorrow, but it still cuts as good as it did the first time.

I can't imagine anyone trying a CBN wheel, and going back to a friable wheel, if time means anything to you. Two minutes on a Tormek, is 5 seconds on mine (maybe 3). Not to mention, the diameter of the wheel never changes, and there is no need for dressing.

I've posted this picture before, but if runout was a problem, I don't think this stuff would have balanced on the grinder while I went to the truck to get the camera. I think maybe I still haven't thought to tighten those nuts holding the grinder down to its plywood base.

ian maybury
03-14-2015, 3:40 PM
Hi Tom. Just in case - i'm not arguing against CBN wheels, only suggesting that they may need a bit more care in choice of bench grinder they run on for sharpening edge tools than a friable stone. Those Metabo machines look dead nice, and your experience confirms that. I thought of one, but could find one locally or in low speed format..

Tom M King
03-14-2015, 4:04 PM
Yeah, I dont' think Metabo makes a slow speed one. I decided to try a regular, full speed one to see what it would do, and it works fine. You just need a good touch, or too much could be taken off so quickly by anyone who is normally heavy handed. If anyone does go this way, develop the touch with cheap chisels first.

Chris Parks
03-14-2015, 9:03 PM
You don't need a dial indicator to clock the concentric run out of a wheel. Fix a piece of stiff wire to the grinding rest and use a feeler gauge to set the gap from the end of the wire to the wheel. Turn the wheel by hand and see if it runs out and measure the smallest air gap with feeler gauges.

Derek Cohen
03-14-2015, 9:03 PM
Ian, your comment about the "lack od adjustability" is spot on. Friable wheels, whether they are used on the Tormek or a dry grinder, may be trued or adjusted to run parallel to the BGM-100. With the CBN wheel, one has to adjust the BGM-100 to the wheel. Because it is not friable, it must be made perfectly flat and the machine must run true. There are many ways for this system to go wrong. When it comes together it is a delight, effortless, nothing short of amazing. But getting it there is not for the faint-hearted, and for this reason I will only recommend this combination with the above cautions.

The second method of setting up a grinder for flat work is the one advocated by Joel Moskowitz, who published an article in FWW magazine several years ago. This uses a wheel with a radiuses/convex face. I think that this (single point) design wheel does reduce many of the problems above, and it is the one I would use if freehanding (it is what I used when I had a white wheel). However it cannot be used with the BGM-100, which required support across the width of the bevel face.

It seems to me that lathe chisels are far more tolerant of inaccuracies in the grinder wheel. With the exception of a skew chisel, most have rounded bevels. Most lathe chisels are used off a grinder. Heat is not a concern these days because HSS is the norm, and M4 is creeping in. Carbide is available. High grit CBN wheels are now becoming available. These produce a high enough level of polish for turners, but remain inappropriate for flat woodworkers. Further, that there is no need to grind past 180 grit smoothness for flat woodworkers since one will still need to refine the bevel with (say) waterstones. Therefore just grind to a point where you reduce the need for one stone. I was trying to explain this point to a turner on a turning forum, but he did not get it. In short, what works for one group does not necessarily work for the other.

I think that CBN wheels are amazing. But we will need to use them to their strengths, which will require a system that does not rely on friability.

Regards from Perth

Derek

dan sherman
12-28-2015, 2:08 PM
Derek,

Any chance you can give us an update? How is the flat wheel doing at grinding chisel and plane blades 9 months later, are they still nice ant strait?

ken hatch
12-28-2015, 9:30 PM
Ian, your comment about the "lack od adjustability" is spot on. Friable wheels, whether they are used on the Tormek or a dry grinder, may be trued or adjusted to run parallel to the BGM-100. With the CBN wheel, one has to adjust the BGM-100 to the wheel. Because it is not friable, it must be made perfectly flat and the machine must run true. There are many ways for this system to go wrong. When it comes together it is a delight, effortless, nothing short of amazing. But getting it there is not for the faint-hearted, and for this reason I will only recommend this combination with the above cautions.

The second method of setting up a grinder for flat work is the one advocated by Joel Moskowitz, who published an article in FWW magazine several years ago. This uses a wheel with a radiuses/convex face. I think that this (single point) design wheel does reduce many of the problems above, and it is the one I would use if freehanding (it is what I used when I had a white wheel). However it cannot be used with the BGM-100, which required support across the width of the bevel face.

It seems to me that lathe chisels are far more tolerant of inaccuracies in the grinder wheel. With the exception of a skew chisel, most have rounded bevels. Most lathe chisels are used off a grinder. Heat is not a concern these days because HSS is the norm, and M4 is creeping in. Carbide is available. High grit CBN wheels are now becoming available. These produce a high enough level of polish for turners, but remain inappropriate for flat woodworkers. Further, that there is no need to grind past 180 grit smoothness for flat woodworkers since one will still need to refine the bevel with (say) waterstones. Therefore just grind to a point where you reduce the need for one stone. I was trying to explain this point to a turner on a turning forum, but he did not get it. In short, what works for one group does not necessarily work for the other.

I think that CBN wheels are amazing. But we will need to use them to their strengths, which will require a system that does not rely on friability.

Regards from Perth

Derek

Derek,

Ain't that the truth.

I fiddled and fiddles to get the BGM-100 adjusted parallel on my low speed 8" grinder. It works but with the 10' Tormek CBN wheel it was off with old on with the new and go to work. Not a cheap solution but if you have a Tormek I think a good solution. I may change my mind after use but I wish I had known about the Tormek CBN wheel when I started down this road.

ken

John K Jordan
12-28-2015, 11:15 PM
is the slight concave center is purposeful for rounded turning tools

I primarily sharpen lathe tools and have two CBN wheels, one with rounded corners. Both are flat otherwise. I think a wheel that wasn't flat in the middle would not be desirable for lathe tools, for example, it would make it difficult to sharpen a skew. Concavity in the center must be a goof in the productions.

JKJ

Derek Cohen
12-28-2015, 11:57 PM
Derek,

Any chance you can give us an update? How is the flat wheel doing at grinding chisel and plane blades 9 months later, are they still nice ant strait?

Hi Dan

Flat. No issues as all. Highly recommended.

Regards from Perth

Derek

dan sherman
12-30-2015, 11:50 AM
Hi Dan

Flat. No issues as all. Highly recommended.

Regards from Perth

Derek

Thanks for the update, I'm getting ready to pull the trigger on one for my new grinder, and it's good to hear that it's still flat.

Don Orr
12-31-2015, 11:32 AM
Very interesting information-thanks for all the input. I may have to look more seriously at these wheels. I have been hesitant due to something I read in several places about softer metals loading up CBN wheels. As mostly a turner, I use a lot of HSS tools but also play with hand tools a lot. I was lead to believe CBN was originally designed for harder, tougher HSS instead of softer mild or tool steels. I do know one should never grind very soft non-ferrous metals on CBN due to loading, but is there any real concern with the tool steels commonly found in hand tool blades. It seems that you have had no issues in this regard. Can you please share any insights on this? Question is for anyone using these wheels on these steels. Thanks.

John K Jordan
12-31-2015, 11:58 AM
Hi Don,

I have two CBN wheels now (one on the Tormek) and just ordered a third from Ken Rizza. I have used these wheels on both HSS and high carbon steel for turning and otherwise and have seen no loading with the standard tool steels. From what I've read elsewhere hardened steels in general should be no problem.

Reed Grey addresses this nicely:

"The advice on what you can and can not grind on CBN wheels differs a bit from manufacturer to manufacturer, but general advise is not to grind non hardened steel or other softer, non magnetic materials on them. Main reason is that they can load up and the wheel might be damaged. I have ground my bench chisels on them, and they work fine, with no loading at all. .... To me, this means, save the old grinding wheels if you want to grind away some soft steel or other things. You might get away with it a time or two, but for anything but the lightest touch ups, keep it restricted to hardened steels, not soft carbon..."
http://www.robohippy.net/featured-article/

BTW, I just noticed the other day that Ken is now carrying flat CBN hand hones in a great size: 2.75"x8". He orders these with a choice of two grits, one on either side. I ordered one yesterday with 300/600 to try it out. This might be just the thing for some of my carving tools. If it works out I might get some finer grits.
http://woodturnerswonders.com/collections/unique-tools/products/hand-hone

JKJ

dan sherman
12-31-2015, 12:16 PM
I'd echo what Reed said, CBN turning inserts (for metal working) are recommended for materials over 45 HRC. High carbon steels like 1085 & 1095, are well over that in their hardened state.

Kees Heiden
12-31-2015, 2:55 PM
HSS steel is not harder then good old high carbon steel. Practical values for both are in the 60 - 62 HRc range. HSS wears a lot slower because of all the alloys and it keeps its hardness at much higher working temperatures. I also don't think the common HSS steels like M2 and M4 are much tougher when toughness is defined as how well the steel survives impact damage usually tested with a kerf test.

Edit, no indeed according to Crucibel steels. M2 and M4 are less tough then A2 for example.

328284

Patrick Chase
12-31-2015, 3:20 PM
HSS steel is not harder then good old high carbon steel. Practical values for both are in the 60 - 62 HRc range. dSS wears a lot slower because of all the alloys and it keeps its hardness at much higher working temperatures.

Some of the more modern PM high speed steels can be taken to much higher hardness than that. Crucible claims Rc >70 for CPM Rex 121. The HAP-40 in my PM-HSS chisels is hardened to Rc 66 or so.

For that matter, the M4 datum in the Chapy C-Notch comparison you posted likely corresponds (https://www.crucible.com/eselector/prodbyapp/highspeed/cpm4hch.html) to a hardness of Rc 63.5.

Kees Heiden
12-31-2015, 3:53 PM
I believe you immediately, but in the context of "CBN wheels are for hard and tough HSS turners chisels" I think we can easilly take the M2 or M4 example, and compare it to A2. If I am not entirely out of mind then I think O1 is even a little tougher then A2 at the same hardness.

Patrick Chase
12-31-2015, 4:09 PM
I believe you immediately, but in the context of "CBN wheels are for hard and tough HSS turners chisels" I think we can easilly take the M2 or M4 example, and compare it to A2. If I am not entirely out of mind then I think O1 is even a little tougher then A2 at the same hardness.

Yes, but... Toughness both as classically defined (area under the stress-strain curve to failure) and as measured by the Chapy C-Notch test aren't the same thing as or even correlated with "abrasion resistance". In that sense I think we're discussing the wrong thing here, and I probably should have come out and said that rather than quibbling with your numbers :-).

HSS is *very* wear-resistant stuff despite its lack of classical toughness. Carbides are a much more extreme example of very low toughness and very high abrasion resistance.

I think that if the original statement had been worded "CBN wheels were designed for abrasion-resistant HSS alloys" (which is a true statement AFAIK) we wouldn't be arguing about it...

Kees Heiden
01-01-2016, 3:07 AM
I think we are in total agreement here.

Marty Schlosser
01-01-2016, 8:51 AM
Thanks for sharing this important issue with us, Derek. Happy New Year to you and your gal.


Hi Matthew

Some have reported a slight concave, like mine, and others have not found this. I don't know what to conclude. I have had a report from the factory to say that the section between the radii is ground flat. The radii are ground after the faces are ground flat, and it could be that on some wheels this pushes the steel up a little - I am hypothesising here. Please do not take this as fact. The point is, however, that the radiused wheels are fine for turners and that the straight wheels are probably better suited to flat woodworkers. I trust this assumption enough to get two replacement wheels, both straight.

Regards from Perth

Derek

Tom M King
01-01-2016, 9:01 AM
I've been using the same radiused edge wheel like Derek had trouble with for something over two years now. Mine was never dished, and has remained flat. I've never used the curved edges for anything though, and if I ever get another one, it will be a flat one.

I doubt I will ever use anything else for grinding on chisels and plane irons, just like I won't ever have another car or truck with cranks to roll the windows up and down.

Mike Holbrook
01-01-2016, 10:46 AM
I was removing the edge that came on a Veritas PM-V11 plane blade, made for Stanley type planes, last night. I will use the blade on a Stanley 5 1/4 plane. I intend to use the smaller width blade more as a scrub type plane. I marked a 8" radius on it and ground it down slow, which on a CBN wheel is very fast. I was working "slow" because I was checking for any issues of the nature Derek mentions in this thread and trying to maintain a relatively precise radius and hollow ground edge. I am not seeing the issue Derek mentions probably due to my Stuart Batty tool rest, from Woodworkers Emporium. I run it on a relatively cheap Delta Variable Speed grinder. I have noticed significant visual wobble on start up with both my wheels. I have been checking for it as I believe I read some of the same things Ian has about the arbors, threads etc. on these machines. I have a set of the washers Ian mentions which thus far have not dialed out the wobble.

Although I have not seen the issues I have some concerns about damaging my wheels on a grinder that costs less than they do. I have had issues with this particular Delta Variable speed grinder due to the body shape and arbor length apparently being different than older models. The arbor on my grinder is so short all the threads on the locking bolts do not extend all the way through, which adds to the issue of dialing in correction. I can set a small wood screw on the center of the machine with it running and the screw stays in place but movement is occasionally visible on the tip of the screw and I can feel vibration in the body of the machine. It may be that having a slightly wider heavier wheel on one side and a thinner aluminum wheel on the other contributes.

I like my SB tool rest. I have the one with the round rear section. It holds a plane blade very steady against the wheel. Once I figured out how to use the SB devise for setting the tool rest angle to the wheel that has become very easy and precise too. I am able to hand grind hollow radiuses in plane blades with very little effort. I should say I have had a great deal of difficulty doing this on my Tormek or other grinder and belt sander set ups. I am apparently "grinder impaired" but have no problems hand working plane blades on this rest. I can even relieve the corners of a plane blade relatively precisely with little difficulty. I think the fact that the CBN wheels cut fast enough for me to see what is going on helps a great deal. I can work at a pace that gives me a relatively precise hollow grind all along the radius, adjusting out any error with minor effort. I thought I would like the sliding attachment on my Veritas tool rest for working plane blade. After trying it a few times though I just took it off and use the Veritas without it. I am thinking about replacing the Veritas with another SB. I suspect that, as Derek mentioned above, the ability to adjust and move my plane blades during grinding allows me to compensate for any error in the wheels, arbor, grinder...regardless, the system is allowing me to do things I have struggled with for years on other systems.

Tom M King
01-01-2016, 1:47 PM
I bought two different grinders, and sent them back, before I found one smooth enough for me. Having no vibration makes a big difference. CPO is a great place to deal with. I just wish Metabo made a slow speed grinder, but I've gotten used to the regular, full speed one. I'm also using the Veritas stand, which is amazingly stiff. Sometimes I use the jig on it, but most of the time not for plane irons, but do for chisels.

Mike Holbrook
01-03-2016, 10:19 AM
I came close to returning the Delta grinder Tom, If I could have found another slow speed grinder that wasn't too expensive I would have done it. Tools for Working Wood offers slow speed Baldor Grinders they customize but they are not cheap and I think some of the mods are directed at stone wheels. I got lost in the dizzying array of grinders out there. I made a post on the subject a long time ago but still did not come up with the solution I was hoping for. I may just buy a Baldor at some point but I am concerned about whether or not the specific jigs I will want to use will fit properly or not. I would like a grinder set up that works well with CBN wheels and tool rest like the Stuart Bally and the OneWay Wolverine. Who is CPO? If they are ok with taking a return if things do not fit they may be the place to buy from.

Tom M King
01-03-2016, 5:28 PM
328469I don't think there is such a thing as a cheap, smooth, slow speed grinder. I've posted this picture enough that some are probably tired of it. This was the first day I stuck the wheel on this grinder. I kept setting stuff on it, and finally went to the truck and came back with the camera. It still runs that smooth a couple of years later, and I don't know if I ever tightened those nuts down or not. I have a really old Baldor grinder on a pedestal in the mechanic/metal shop that belonged to my Dad. It's still smooth as can be, but I didn't want to drag that one around, and it gets used for metal, and I didn't want to spend that much for another one either.

Do a Google search for CPO tools. It'll come right up. I don't think I've bought a power tool from anyone else for some years. I got a couple of "refurbished" 7518's from them cheap, and they were like new, as was a 2" 23 ga. pinner a couple of weeks ago. I always look for their reconditioned tools as first choice when I'm looking for something. I think the return label comes in their box. Quick shipping, best prices, and easy returns.

Mike Holbrook
01-05-2016, 10:22 AM
Derek,
I am wondering if you have tried hollow grinding the thicker Veritas plane blades used in their bevel up planes using a CBN wheel? I have read your post about grinding 25 degree bevels on all of these blades and then making a much smaller "micro" bevel to alter the plane blades angle of attack and to sharpen it. I am just wondering if the much greater speed of the CBN wheels might finally make it reasonable to just hollow grind these blades? I have a couple PM-V11 and A2 38 degree BU blades that I have put off working until I figure the CBN wheels out better.

I believe I can regrind the blades with the CBN wheel. I am just wondering what a hollow grind in an edge that wide would end up like functionally. Using the normal surface of the CBN wheel ends up making a hollow unless the one doing the grinding does something different, I do have a CBN wheel that has a flat side with abrasive on it, but I don't know how hard it might be to grind one of those wide edges flat using the small area on the side. I am not excited about regrinding 38 degree BU blades to 25 using a stone or diamond plate. Maybe Derek has ground flat bevels on the side of a Tormek wheel or a belt sander?

I am using my old Stanley planes for the rougher work, requiring more cambered blades. The thinner blades are easier to grind cambers in for one thing. In my case this means my Veritas BU planes" jointer, LA jack, BU smoother and BU block will need only minor cambers or rounded edges, some or most of which might be done during the honing rather than the grinding.

Reinis Kanders
01-05-2016, 11:36 AM
I have ground some of my PMV11 BU blades to around 35 degrees. I do not camber though, this is for my BU Jointer that I use for the edge jointing. Seems to be ok, but my standards are fairly relaxed. I would not bother to grind all the way back to 25 unless you want it for the endgrain. At 35 degrees tearout is not much of an issue with the jointer.

Derek Cohen
01-05-2016, 1:01 PM
Derek,
I am wondering if you have tried hollow grinding the thicker Veritas plane blades used in their bevel up planes using a CBN wheel? ...

Hi Mike

I have not compared an 8" hollow with the 10" hollow (which is shallow) or a flat primary bevel (which is not too different to a 10" hollow). Part of the reason is that I have moved increasingly to double iron planes.

I do use a straight 40 degree bevel on a BU Jointer. I use a cambered blade on a Custom (BD) #7.

Regards from Yorkshire

Derek

Mike Holbrook
01-05-2016, 10:52 PM
Derek,

Thanks for the update. Sounds like there is a dearth of information on the topic, unless Reinis means he hollow ground a BU PM-V11 to around 35 degrees. I guess I will be breaking new ground. I think I will try an older A2 BU first, mine are use to being tortured over the years. Sounds like Derek is growing fond of the new Veritas BD planes.

Derek I missed a question you asked earlier in this post about deflection of the universal bar on a Tormek. I finally found the answer, which I believe to be unique to early model machines. My older Tormek, 2000, does not have a locking knob on the left side of the mechanism for holding the bar in place, which all the other models do have. Even when I have the right locking knob and the locking washer up tight against the right side, I have discovered that the left side moves within the housing. I missed this for years because it looks solid and is hard to see until you start playing with the end of the universal bar looking specifically for deflection. I might never have found it if Derek had not posted about the need for the bar to remain dead parallel to the wheel surface, even though I was suspicious that something was going badly wrong. I can deflect the end of the bar on mine by something like 3/8" with fairly light pressure. I am fairly sure this is why I have had such a horrible time getting consistent results.

Seems like Derek is bringing the new year in with a little travel, Scotland now England, stay safe and bring back some good info. on proper english woodworking.

Patrick Chase
01-06-2016, 1:27 AM
I came close to returning the Delta grinder Tom, If I could have found another slow speed grinder that wasn't too expensive I would have done it. Tools for Working Wood offers slow speed Baldor Grinders they customize but they are not cheap and I think some of the mods are directed at stone wheels. I got lost in the dizzying array of grinders out there. I made a post on the subject a long time ago but still did not come up with the solution I was hoping for. I may just buy a Baldor at some point but I am concerned about whether or not the specific jigs I will want to use will fit properly or not. I would like a grinder set up that works well with CBN wheels and tool rest like the Stuart Bally and the OneWay Wolverine. Who is CPO? If they are ok with taking a return if things do not fit they may be the place to buy from.

I have the same Delta variable-speed 8" grinder and was dissatisfied with the amount of wobble/vibration even with CBN wheels. Traditional wheels were a disaster, requiring endless fiddling with the washers to get even halfway-decent performance.

I upgraded to the half-speed Rikon from Highland Woodworking, and it's a night and day difference. I can balance 2" 1/4-20 screws on end on the housing while it's running with either type of wheel, just like Tom can with his Metabos. Admittedly the fact that the Rikon is only running at 1750 rpm makes that somewhat less impressive, but it's still a very smooth-running grinder. As Highland says, the washers are very thick with ample registration on the arbor and inner flange, so they serve to stabilize conventional wheels (they don't help CBN, but the bushings for CBN wheels serve the same purpose).

One useful benefit that isn't listed on the product page is that it has a built-in wheel brake that auto-triggers below a certain speed. With conventional wheels it takes about 20 sec to come to a complete stop. Changing a single wheel from conventional 8x1 to 8x1.5 CBN adds about 20 sec to that (mostly spent spinning down to the brake's trigger speed), so the grinder takes about a minute to spin down with 2 CBN wheels.

Reinis Kanders
01-06-2016, 10:12 AM
I hollow ground it on 180 CBN wheel. to 35 degrees, worked fine.


Derek,
unless Reinis means he hollow ground a BU PM-V11 to around 35 degrees.

Reinis Kanders
01-06-2016, 10:14 AM
I learned from the D-way videos that one can easily stop these wheels via friction by holding up a rag to the wheels side. I use an old rag, works well.



One useful benefit that isn't listed on the product page is that it has a built-in wheel brake that auto-triggers below a certain speed. With conventional wheels it takes about 20 sec to come to a complete stop. Changing a single wheel from conventional 8x1 to 8x1.5 CBN adds about 20 sec to that (mostly spent spinning down to the brake's trigger speed), so the grinder takes about a minute to spin down with 2 CBN wheels.

Patrick Chase
01-06-2016, 10:18 AM
I learned from the D-way videos that one can easily stop these wheels via friction by holding up a rag to the wheels side. I use an old rag, works well.

I use a block of MDF as a brake on the Delta. Same idea :-)

Stewie Simpson
01-07-2016, 12:26 AM
http://i1009.photobucket.com/albums/af219/swagman001/electro%20dental%20polishing%20machine/_DSC0103_zpsttaqohud.jpg

http://i1009.photobucket.com/albums/af219/swagman001/electro%20dental%20polishing%20machine/_DSC0104_zpsaqrckn0y.jpg (http://s1009.photobucket.com/user/swagman001/media/electro%20dental%20polishing%20machine/_DSC0104_zpsaqrckn0y.jpg.html)

Stewie Simpson
01-07-2016, 1:30 AM
3 Speed machine; 240V;1 AMP; 50HZ;
Manufacturer ELECTRO DENTAL, Sydney Australia.

Stewie Simpson
01-07-2016, 2:10 AM
Watch this video from 10.30 min. to see how complex sharpening a plane iron needs to be; also note the top surface of the stone looks to be slightly bellied.

http://www.rts.ch/play/tv/la-suisse-au-fil-du-temps/video/les-outils-de-bois?id=3464421#t=27

Stewie;

Derek Cohen
01-07-2016, 3:34 AM
I learned from the D-way videos that one can easily stop these wheels via friction by holding up a rag to the wheels side. I use an old rag, works well.

Hi Reinis

I press a finger (!) against the inside of the wheel to act as a brake. I would say that a rag or, better, a piece of leather (finger of a defunct glove) would be better, however the steel is smooth and a resulting grimy finger can be washed. :)

Try that on your set up, Stewie!:eek:

Regards from Perth

Derek

Stewie Simpson
01-07-2016, 7:30 AM
Derek. If your stupid enough to put your finger where it shouldn't be to slow down a 2800rpm grinding wheel;

Stewie;

http://i13.photobucket.com/albums/a262/Derek50/CBN-flat2_zpsyleve1mf.jpg

Pat Barry
01-07-2016, 8:05 AM
What is the fascination with this? Why not just walk away and let er spin down???

Reinis Kanders
01-07-2016, 1:36 PM
I usually do just that, but in more public setting it probably is not a good practice to just walk away and leave a spinning machinery.


What is the fascination with this? Why not just walk away and let er spin down???

Derek Cohen
01-07-2016, 2:31 PM
What is the fascination with this? Why not just walk away and let er spin down???

Hi Pat

A more serious answer - most of the time I do let it run down, but when grinding more than one blade, you need stop the wheel to set the angle. These CBN wheels run so smoothly (because they are so well balanced), that their own momentum lasts a long, long time. Many, many times that of a white wheel ... 10 minutes after the power was switched off they are still spinning!

Regards from Perth

Derek

Tom M King
01-07-2016, 4:51 PM
The other reason that I don't put another wheel on the other end my the Metabo, other than I don't need but the one, is that if I did, and turned it off today, it would probably still be spinning tomorrow. With no vibration, and no fan to make noise, it doesn't make enough noise to notice, and at 3k+ rpm, it's got a good start.

John K Jordan
01-07-2016, 7:18 PM
...turned it off today, it would probably still be spinning tomorrow

Ha! My Metabo is the same - it's the best of all my grinders. But I can see the silent rundown could be a problem with more than one person in the shop. I wonder if adding a small plastic vane or even a piece of tape somewhere would add enough noise to alert it's still spinning. Mine is in my weld shop and I have a wire brush on one side which makes plenty of air noise.

JKJ

Lasse Hilbrandt
01-26-2016, 7:11 AM
Derek. Is there such a thing as a CBN flat stone ?

Derek Cohen
01-26-2016, 7:34 AM
Hi Lasse

Yes. D-Way sell one. I think it is 600 grit. There may be another as well.

Regards from Perth

Derek

Lasse Hilbrandt
01-26-2016, 10:44 AM
Thanks, I just ordered the 360/600 Grit plate. Its going to be very interesting how they perform manually

Patrick Chase
01-26-2016, 11:00 AM
Thanks, I just ordered the 360/600 Grit plate. Its going to be very interesting how they perform manually

CBN is mechanically softer than diamond, and is bonded to the plate in exactly the same way. The only reason to prefer CBN to diamond is for cost/availability and maybe to avoid carbon exchange between the wheel and the workpiece, but only if you're grinding HSS at temperatures approaching 700C (the threshold/activation temperature for the aforementioned carbon exchange reaction. It's a nonissue below that).

Neither of those applies to D-Way's hand hones...