How essential is a bench grinder for sharpening chisels?

[Luis Reyes]

I'm sure this topic will cause a lot of debate but here's my specific situation. I have narex chisels which I've sharpened by hand with waterstones and I'm ok with (bought new from Lee Valley). It took me a while but I'm good with those. I bought about 10-15 chisels at a yard sale that are old and need a lot of work to bring back. Some are probably junk which may not even be worth the effort but I don't mind finding a little time to bring them back. I think there were 2-3 marples and sorby as well. Is it worth getting a grinder to help create a good primary bevel on the older chisels?

There's a delta 23-681 close to me for $40 that I'm thinking of buying but almost feels like I don't really need it? What's the group think

I should also add I'll probably try to find more chisels at yard sales this coming summer!

[Chuck Hill]

It depends. :-) If you are going to develop a used chisel problem then you probably want one. You will also probably want a better wheel. This is the best source that I know of for all things related to grinding woodworking tools:
https://www.inthewoodshop.com/WoodworkTechniques/index.html

For a bit more money you can get this slow speed grinder. I have one and it is worth the money, vibration free and enough power to do what you need. Toss the wheels that come with it. They are garbage.
https://www.amazon.com/gp/product/B091GRDLKQ

[Luis Reyes]

Haha I think I am developing a used chisel problem to look for those diamonds in the rough! If I get a grinder I'd probably get a CBN Wheel though which is probably adding to my indecision because now it's not just a $40 grinder but a $40 grinder and $110 CBN wheel.


It depends. :-) If you are going to develop a used chisel problem then you probably want one. You will also probably want a better wheel. This is the best source that I know of for all things related to grinding woodworking tools:
https://www.inthewoodshop.com/WoodworkTechniques/index.html

For a bit more money you can get this slow speed grinder. I have one and it is worth the money, vibration free and enough power to do what you need. Toss the wheels that come with it. They are garbage.
https://www.amazon.com/gp/product/B091GRDLKQ

[mike stenson]

I just use a norton wheel. I don't see a need for a CBN wheel. Note: I said need. Y'all may want em.. but need is a different thing entirely.

[Chuck Hill]

Read the stuff that Derek wrote. Make sure you get a CBN wheel that is flat side to side. I agree that a CBN wheel is not a need but it greatly reduces the chance of over heating the steel for someone new to grinding. There is also less mess and close to no chance that the wheel will turn into a grenade so no need for the metal shield around the wheel. Yes, I had that happen once. I really like my CBN wheel now.

If you do get a grinder, put a deburring wheel on the other side. They are great for cleaning up the rustina on old tools:
https://www.amazon.ca/Nylon-Fiber-Buffing-Grinding-Polishing/dp/B0B3L6YYC1/

I think I got that idea from Timberwolf, many years ago now.
https://www.amazon.ca/Nylon-Fiber-Buffing-Grinding-Polishing/dp/B0B3L6YYC1/

[Ben Ellenberger]

If I wasn’t in an apartment and had power in my shop I’d get a grinder today (I wouldn’t wait until tomorrow, even though it’s after 8 pm my time). That being said, I use a piece of granite with 80 grit adhesive-backed sandpaper when I need to really re-shape something. It’s pretty effective.

[Rafael Herrera]

A bench grinder is a useful tool to have in the workshop in general.
The one I have is closer to 20 years old and still has the original wheels. You can certainly spend quite a bit of money in CBN wheels and what not, but don't be persuaded they're essential.

On another note, a coarse crystolon can handle any vintage chisel in need of a refreshed bevel, 80 grit sandpaper too, as noted above. The advantage of the crystolon oilstone is that you won't be needing to put on the darned mask or ear muffs.

[Jim Koepke]

Luis, there are many options for the craftsperson who wants to accumulate a lot of blades in need of some TLC.

The grinder for $40 sounds like a good deal as long as the motor is sound. It is hard to find a decent motor at that price. The advantage of a grinder is it will produce what is called a hollow grind. This makes free hand honing a lot easier.

My choice was for a flat faced grinder system. The advantage here is when flattening the backs of blades.

This one received a good review in Fine WoodWorking at the time of my being in the market > https://www.leevalley.com/en-us/shop/tools/sharpening/power-systems/48435-veritas-mk-ii-power-sharpening-system?item=05M3101

If you choose this system buy a few extra abrasive disks of each grit. Also buy multiple tool holders. For me five was about right. That would let me work on a batch of blades at one time. The first one would heat up and then be set aside. By the time the fifth blade was worked, the first one would be cool enough to work on again.

There are two thicknesses of platters available for this. Because of the different thicknesses of the abrasive sheets there is a tendency for this to create a secondary bevel. If one wants a single bevel, it isn't difficult to shim up the platter to produce a single bevel. Once my blades are sharp they do not often require a return to power sharpening.

Now that my chisel accumulating has slowed down my four foot granite slap gets most of the work:

498651

This was purchased from a monument maker (tombstone carver) about twelve years ago.

This with some Pressure Sensitive Adhesive backed abrasive paper from a roll cleans up a blade real fast. Most of the time this is used with 360 paper. That is fast enough for plane soles and also pretty fast with a blade in a honing guide. My honing guide is one of the tool holders for the Veritas System with a shop made roller:

498652

Shown here with its first roller made of wood. Later a roller was made out of some plastic that was given to me by a machinist.

BTW, don't knock the lesser branded and unbranded chisels. It is always handy to have beater chisels around if someone wants to borrow one or you have to do some work on dirty wood.

I sharpened up a bunch of second tier chisels and gave them to a friend I thought wanted to do some woodworking. They reported back that they worked great at removing their bathroom tiles.

jtk

[Maurice Mcmurry]

I find my bench grinder very useful. Since I bought an inexpensive Grizzly copy of the Tormek wet grinder and strop, chisels and plane irons are cared for there. +1 for having a de-burring wire wheel. A muslin buff is also great to have.
Grizzly puts these on sale for $99.00 from time to time.

498669

[Ernie Hobbs]

I've been building furniture for 30 years and many gadgets for sharpening- but the most effective method for me is my old trusty bench-mounted 4 x 36 belt sander with a 220 grit belt (or a worn out 150 grit belt) and a few passes on buffing wheel on my grinder. Once you get a feel for the angle of the chisel, just do it free hand without all of the jigs. I can sharpen a chisel in 15 seconds and get back to work.

[David Carroll]

It's certainly not the first thing I would go out and buy. I have a lot of grinding/sanding equipment at work, so when I need to do major work on a chisel, plane blade, or hatchet, I take it in and do it there. Of all the equipment I have at my disposal there, I use the Burr-king 2-inch belt grinder the most. If I didn't have these available I would likely buy a smaller belt grinder of the type that knifemakers use.

About 10 years ago I bought a Tormek grinder from somebody here (I think). It's a beautiful machine. I don't use it very often, and mostly for lathe tools. But when I have to re-establish a primary bevel on my beater chisels, it works great!

The rest of everything I do on stones. I've recently changed to diamond stones (Well, 10-ish years ago). Before that I used Scary-sharp on plate (float) glass and before that oil-stones.

DDC

[mike stenson]

I also have a tormek. It's too slow in my opinion. It's well built, and it certainly does what is advertised though. Really, just paying attention prevents burning an edge.

[Reed Gray]

If you are in to turning, then a slow speed grinder is essential, and gets used multiple times a day. For your bench chisels, I would consider it more useful for shaping and getting the bevel angles you want. This would require a good platform since most that come with the grinders are junk, and that is being polite. You may be able to find a community center that would let you use their grinder. A saw sharpening service may be able to do it for cheap if you can explain what you need so that they understand it. Once you have your angles, you probably won't need it again, unless you drop your chisel on the concrete floor.

A $40 grinder???? Well, I would guess it is a 6 inch high speed grinder with narrow wheels. The wheels that come with the grinders are generally very coarse, with the fine side being 60 or 80 grit. That may do for getting the shape you want, but is extremely coarse. Standard for most turners is a slow speed 8 inch grinder. My preference for wheels is the CBN wheels. One reason is that they are spin and bubble balanced before going on your grinder. Another advantage is that they will never break. They are good for any 'hardened' metal, which includes bench plane irons and bench chisels. The CBN wheels have a life span in a production shop of about 5 years. They are heavier than standard friable grinding wheels, so you may need a more heavy duty grinder.

As for the wet wheel very slow speed grinders, they are made for this, but as said above, they are very slow for any heavy stock removal. They have diamond wheels for them now, in grits up to 1200, and can sharpen anything in your house.

I do have a Jet 1 1/2 hp belt sander for any serious shaping I need to do for my lathe tools.

robo hippy

[roger wiegand]

I use a bench grinder on the set of Sears chisels I keep for wood with nails in it. Other than those none have ever needed a power tool for sharpening (I'm fortunate in not having taken a serious chip out of any of my "good" tool. The Rikon with CBN wheels is essential for turning tools, though even with those I sharpen at the grinder much less often since I got a nice teardrop diamond hone.

[Mel Fulks]

Old timers used a flat bevel . Then all they needed was a coarse stone ,and a fine stone. Some guys can use a small cheap high speed
grinder for a just the right amount of time, then quickly cool in water , and repeat .

[Rafael Herrera]

The OP is not asking if he can sharpen with a bench grinder. He has and will get old chisels that will likely need their primary bevel restablished. The grinder is as good as any other method, and certainly faster than a Tormek.

[steven c newman]

Grinder in the Dungeon shop..sees a lot more than just sharpening..
498709
Name plate?
498710
For most of the sharpening going on...there is this...and a big glass of water...
498711
There IS a second, older grinder, set up for doing the "Unicorn" ....

Just how this shop works..others? Meh...

[Robert Hazelwood]

I'd say pretty essential...and not even so much for restoring old chisels, but for routine maintenance in refreshing primary bevels to reduce the size of the secondary bevel you have to hone. You'll find other uses for it, too, no doubt.

You can overcome the lack of one in several ways, however. If you have a belt sander of some kind, you can probably rig up a way to grind on it. Derek Cohen had a writeup on modifying a stationary belt sander to grind bevels- it may still be up on his site. I adapted his idea to my 1x42 belt grinder and that's what I use. I wouldn't suggest buying a belt sander for this purpose if you don't have one, although I think my setup works pretty well. Make sure to use a fresh coarse grit belt (less than 100 grit) to avoid overheating.

You can also grind them by hand. The best way would be on a long sandpaper lap. Get a roll of 80 grit PSA paper and a long (say 2 ft long or more) strip of plywood or something- doesn't need to be perfectly flat for bevel work. Chuck the chisel in a cheap eclipse style guide and go to town. If the paper is fresh you will be surprised how quickly you can remove material. If you aren't trying to make a drastic change to the bevel angle, then this should go very quickly. If you don't want to fool with sandpaper, a coarse Crystolon stone is about the fastest stone I know of.

[Richard Coers]

A grinder is invaluable for me. It takes less than 5 minutes of honing after establishing a perfect bevel on the grinder.

[Scott Winners]

I have a 6" grinder, and eventually put a white Norton stone on it. Now that my acquisition phase is largely complete, and I am pretty well over the idea of restoring old tools to save money, I am keeping my grinder for refreshing primary bevels on my edge tools as I use them. As one recent poster mentioned, refreshing the primary bevel to save time sharpening the secondary bevel. Keeper tool.

In the acquisition phase my second most common use for the grinder was a wire wheel brush on the other end of the grinder for rust removal.

I regret not saving up a few more sheckles to first acquire an 8 inch grinder, but at this point upgrading my grinder would not materially affect the quality of my finished work, nor would an 8 inch grinder let material move through my shop faster to become finished product sooner.

One thing to do with intention is get a basket case old chisel to the grinder and overheat it on the grinder so you can get a feel for how long that takes, and then grind away the burnt area -also on the grinder- so you have a reference point for how long that takes. Rather than see how fast I can grind primary bevels without burning, my approach is to instead re-establish a primary bevel on my grinder slowly enough that I don't have to worry about burning the steel. Still faster than by hand, by a LOT.

[john zulu]

Most of the time on the stones. But for grinding I would use a bench grinder. Belt sander is doable but does not produce a concave bevel. You could free hand a few times with free hand on a concave bevel edge. If there is a chip edge then use a bench grinder.

[Thomas McCurnin]

Sharpening is a science in debate.

Old school was a couple of stones on a grinding wheel and either a finishing flat stone and strop. That creates a hollow grind which is easier to maintain with a series of flat stones and a strop. But a grinder can be fussy and inaccurate. A Rikon slow speed grinder upgraded with a Veritas tool rest and jig are great improvements. You can get well over $1,000 in grinders, stones, finishing stones and strops.

A more Neanderthal method (Paul Sellers) uses a series of flat stones which work fairly well, except for tools with nicks. He finishes off the process with a strop. His video on sharpening is priceless. He sharpens tools with stones for under $100.

In the 1980s, someone figured out that sandpaper on a glass was cheap and easy, so enter the world of glass plates and sand paper, with or without a jig to hold the tool. Works well for sharpening, but doesn't work well for fixing nicked blades, as it uses a lot of sandpaper. As one poster suggested a belt sander works very well, and assuming you're good at setting the bevel, works well for the whole process, coarse to fine, but you'll still need a fine stone and a strop. You can pick up a used 4x36 belt sander on Craigslist for under $200 and some have tool rests and you may be able to make a jig for the angle on your tool.

Either method will result in a sharp tool. I don't think either is better than another, although I tend to use my Rikon method more than any.

[Peter Schussheim]

I regret not saving up a few more sheckles to first acquire an 8 inch grinder, but at this point upgrading my grinder would not materially affect the quality of my finished work, nor would an 8 inch grinder let material move through my shop faster to become finished product sooner.


Scott, may I ask why are you regretting not getting an 8" grinder? What about the 6" diameter is less than ideal?

[Warren Mickley]

A grinder is not essential for sharpening chisels. A grinder is not essential for sharpening turning tools.

When restoring old chisels to a serviceable condition, working the bevel is not what takes a lot of work. Getting the back in good condition is what takes time, and a grinder is only marginal help here. And the truth is that given the decades of service a good chisel provides, the time spent bringing the tool into service is trivial when the total life of the chisel is considered.

If you are buying used chisels, I would concentrate on buying intermediate sizes like 5/16 or 7/16. Having multiples of sizes like 1" or 3/4" doesn't do much good unless you are really upgrading or enjoy comparing different brands.

[Jim Koepke]

I mostly agree with Warren's post.

It is convenient to have multiples of one's most used sizes. This allows one to keep going instead of stopping. If one chisel needs the edge refreshed it can be set aside and another picked up to continue the work at hand.

There are four or five sets of chisels in my kit:

1) A set of paring chisels, these are long bevel edged chisels and have short lands.

2) A set of heavier bevel edged chisels, these are for light mallet work.

3) A set of flat sided chisels for use with a mallet.

4) A set of mortise chisels for going deep.

5) A set of butt chisels are handy for working in close.

When working on larger projects my 3/4" and larger chisels are often the ones doing the work.

Here is a 1-1/2" bevel edge chisel paring a cheek for a lap joint:

498809

Here it is paring on a leg for a sawhorse.

jtk

[steven c newman]

Unless a edge has chipped, I rarely ever use the grinder...unless it has the cloth buffing wheel on it.

One other needful item along with a grinder...is a cup of water....when the steel is too warm for a finger..dunk the steel into the cup of water....

Old timers( way before Warren was born) would have a tin can set above the wheel, that one could set to drip onto the wheel, plus you could start out with a "handful" right out of the cup...a BIG improvement came along...when they added a seat, and a couple pedals to turn the wheel...( one for sale about 3 blocks from where I am sitting..)

[Derek Cohen]

I use a grinder much of the time when preparing chisels and plane blades for sharpening. I do not use a grinder for Japanese laminated blades, where the hard cutting layer is thin and the soft thicker backing is easily abraded.

The grinder creates a hollow, reducing the steel area to be honed. This is the same basis for Japanese planes, where the soles are hollowed to improved coplanar and reduce friction. In the case of blades, especially steel which is hard and abrasion-resistant, there is significant benefit in reducing the steel area in regard to speed and effort.

There are other ways to do this, such as honing a secondary bevel, which may be done freehand or with a honing guide. I prefer to freehand on the hollow, which is self-jigging.

Hollow grinding does not wear out blades faster. The steel is removed from the centre of the primary bevel, not the ends. I do not see my blades becoming shorter any faster than someone who only work the face of the bevel.

I grind up to the edge of the blade. This does not affect its hardness unless one is heavy-handed or clumsy. Using CBN wheels helps tremendously to reduce heat in the grind. Grinding is less frequent than one realises at this point since the hollow lasts a long time with an 8” wheel.

https://i.postimg.cc/KxdPCg0g/C3-D0550-F-6291-484-B-8-DDF-8-FBFCA55-FBB9.png (https://postimages.org/)

Edit to add: Sharpening the thin Stanley blades made with plain carbon steel, available for a 100 or more years, is a different story to the modern thick steels of today, which are made of harder and more abrasion-resistant compounds. Basically, what one is doing with hollow grinding, is “tricking” these thick blades into acting like thin blades.

Regards from Perth

Derek

[Reed Gray]

A grinder is not essential for turning???? Well, if you don't do much turning, then that may be true, but as a production turner for 25+ years, it is essential to me.

robo hippy

[Jim Koepke]

A grinder is not essential for turning???? Well, if you don't do much turning, then that may be true, but as a production turner for 25+ years, it is essential to me.

robo hippy

I do not do a lot of turning, but do find a powered system, if not essential, is a real time saver. Turning is much tougher on a tool than hand work.

Consider if one is working on a 2" cylinder turning at 200 rpm a tool touching that surface is engaging with ~100' of wood per minute.

498869

This piece of ash (a work in progress) is maybe 3" (five or six inches overall) and my skew needed its edge refreshed. A few seconds on my powered sharpener sure beats a few minutes or more on my stones.

jtk

[Warren Mickley]

A grinder is not essential for turning???? Well, if you don't do much turning, then that may be true, but as a production turner for 25+ years, it is essential to me.

robo hippy

I do a different style of turning. I use very sharp tools and was able to stop sanding in 1978.

[Edward Weber]

As Jim just touched on, Grinders really aren't essential at all, they are time savers.
With turning, they are used frequently and often, to the point of being essential.
With modern replaceable tip tools one could argue the point.

For sharpening, flat chisels, again it's simply a time saver, faster than using files.

Also grinding a hollow bevel does not increase or decrease the amount of time and steel used.
If you hollow grind once, removing a lot of steel, each successive sharpening before re-grinding takes less steel removal to sharpen.
If you sharpen using a flat bevel, you remove more steel per sharpening but the total amount of steel removed of the two, remains the same.
Remember, you only sharpen as much as you need to, each method is simply a different route to get there.

I use a grinder for turning tools and a benchtop belt sander platen to regrind flat chisel bevels. Each one is a time saver.

[Jason White]

I needed one. Hated the mess the Norton wheel created.


I just use a norton wheel. I don't see a need for a CBN wheel. Note: I said need. Y'all may want em.. but need is a different thing entirely.

[Derek Cohen]

Edward wrote:

Also grinding a hollow bevel does not increase or decrease the amount of time and steel used.
If you hollow grind once, removing a lot of steel, each successive sharpening before re-grinding takes less steel removal to sharpen.
If you sharpen using a flat bevel, you remove more steel per sharpening but the total amount of steel removed of the two, remains the same.

Edward, did you read my earlier post?

I am happy to debate to the death that - in suitably experienced hands - you will get LESS steel wasted with a hollow grind than with a flat grind. The hollow grind only goes as far as the end of the bevel, at most (I generally stop when there is the merest sliver of silver remaining). It can stop even earlier, if you prefer. A flat grind has to go over the edge, since the purpose here is the remove the rounded, worn section of the bevel. The worn section of the hollow grind bevel also needs to be removed, but this is done with waterstones (or other media). With a flat grind you are doing this twice (first with a machine, and second with stones). The purpose of a hollow grind is to remove extra steel to facilitate honing. That is all.

In effect, the amount of steel used up with a hollow grind + honing is the same as a flat bevel without any grinding (as I do with Japanese blades).

Regards from Perth

Derek

[Jim Koepke]

With a flat grind you are doing this twice (first with a machine, and second with stones).

For me, the optimum is only doing the flat grind once on a machine. After that the flat bevel is maintained on the stones. Unless the edge is damaged, my tools do not get taken back for machine abrasion.

jtk

[Maurice Mcmurry]

I absolutely have to have my hollow grind. If I had not had a bench grinder for 40 years my chisels would be a lot longer. I never had fancy wheels for my grinder so it remains too fast, too aggressive, and too hot for chisels & plane irons. My bench grinders are for metalwork, sharpening drill bits, cleaning, and polishing. A very important tool, no longer used for chisels. Time goes fast learning goes slow. I have some very short chisels.

[Edward Weber]

Edward wrote:


Edward, did you read my earlier post?

I am happy to debate to the death that - in suitably experienced hands - you will get LESS steel wasted with a hollow grind than with a flat grind. The hollow grind only goes as far as the end of the bevel, at most (I generally stop when there is the merest sliver of silver remaining). It can stop even earlier, if you prefer. A flat grind has to go over the edge, since the purpose here is the remove the rounded, worn section of the bevel. The worn section of the hollow grind bevel also needs to be removed, but this is done with waterstones (or other media). With a flat grind you are doing this twice (first with a machine, and second with stones). The purpose of a hollow grind is to remove extra steel to facilitate honing. That is all.

In effect, the amount of steel used up with a hollow grind + honing is the same as a flat bevel without any grinding (as I do with Japanese blades).

Regards from Perth

Derek
I don't want to argue to death.
I prefer a flat grind single bevel because I use chisels bevel down. I like that I can positively register my chisel with a full bevel.
You may use the same or even less material with a hollow grind, I agree but it's not for me.
I gave up arguing about sharpening a long time ago, life is too short

[Derek Cohen]

Edward, I also hate discussing sharpening. My response to you was not about sharpening, or even whether grinding is preferred, or not. It was a response to your comment that implied that hollow grinding shortens chisels more than flat grinding, even just honing.

My comment was also to clarify for others that hollow grinding is primarily about reducing the amount of steel to be honed.

I use my chisels both BD and BU. The hollow does not affect this, at least in the way I sharpen, which is on the hollow. This creates a coplaner face. This would not be the case with a secondary bevel.

Regards from Perth

Derek

[Edward Weber]

Edward, I also hate discussing sharpening. My response to you was not about sharpening, or even whether grinding is preferred, or not. It was a response to your comment that implied that hollow grinding shortens chisels more than flat grinding, even just honing.

My comment was also to clarify for others that hollow grinding is primarily about reducing the amount of steel to be honed.

I use my chisels both BD and BU. The hollow does not affect this, at least in the way I sharpen, which is on the hollow. This creates a coplaner face. This would not be the case with a secondary bevel.

Regards from Perth

Derek
Sorry Derek, I may have mis spoke.
I think you wind up the same with either system. Maybe a slight advantage with hollow.
I use one single bevel

[Jim Koepke]

I don't want to argue to death.
I prefer a flat grind single bevel because I use chisels bevel down. I like that I can positively register my chisel with a full bevel.
You may use the same or even less material with a hollow grind, I agree but it's not for me.
I gave up arguing about sharpening a long time ago, life is too short


Edward, I also hate discussing sharpening. My response to you was not about sharpening, or even whether grinding is preferred, or not. It was a response to your comment that implied that hollow grinding shortens chisels more than flat grinding, even just honing.

My comment was also to clarify for others that hollow grinding is primarily about reducing the amount of steel to be honed.

I use my chisels both BD and BU. The hollow does not affect this, at least in the way I sharpen, which is on the hollow. This creates a coplaner face. This would not be the case with a secondary bevel.

Regards from Perth

Derek

This makes me think about an old commercial for a certain brand of mints as to whether it was a candy mint or a breath mint… Stop, your both right!

In experienced hands, Derek is correct. A careful touch of a chisel to the center of a bevel does not remove metal from the overall length of an edged tool.

On the other hand, a lot of edged tools in my history of rust hunting have been 'sharpened' by inexperienced hands who seem to have equated grinding with sharpening.

Many years ago a chisel came to me with a hollow grind:

498900

Over the years it has been freehand sharpened many times. The dark spot at the top edge and near the bottom is all that is left of the hollow grind after all these years. My recollection is this chisel has been in my shop for well over a decade. It is one of my early chisel handles from right after my acquiring a lathe.

So a properly done hollow grind is an effective aid to freehand sharpening. When done carefully will not reduce the length of a chisel or plane iron and it can last a long time before needing refreshing.

Also correct is a flat bevel, when properly maintained will not significantly reduce the length of an edged tool any more than refreshing a hollow ground tool. The difference is a hollow ground edge only removes metal at the top and bottom of a bevel where a flat bevel removes metal from the the entire face of a bevel. When the amount of length removed from a tool in either case is considered, it is probably in the realm of three or four zeros after the decimal point.

jtk

[Jack Dover]

Steven, the disk&belt sander combo is advertised as a woodworking equipment, is it okay to use it on metal? Never been close enough to these machines to see their construction, so I'm imaging that if they have a plastic exhaust or a plastic shroud - that would be a problem, no?

[Edward Weber]

This makes me think about an old commercial for a certain brand of mints as to whether it was a candy mint or a breath mint… Stop, your both right!

In experienced hands, Derek is correct. A careful touch of a chisel to the center of a bevel does not remove metal from the overall length of an edged tool.

On the other hand, a lot of edged tool in my history of rust hunting have been 'sharpened' by inexperienced hands who seem to have equated grinding with sharpening.

Many years ago a chisel came to me with a hollow grind:

498900

Over the years it has been freehand sharpened many times. The dark spot at the top edge and near the bottom is all that is left of the hollow grind after all these years. My recollection is this chisel has been in my shop for well over a decade. It is one of my early chisel handles from right after my acquiring a lathe.

So a properly done hollow grind is an effective aid to freehand sharpening. When done carefully will not reduce the length of a chisel or plane iron and it can last a long time before needing refreshing.

Also correct is a flat bevel, when properly maintained will not significantly reduce the length of an edged tool any more than refreshing a hollow ground tool. The difference is a hollow ground edge only removes metal at the top and bottom of a bevel where a flat bevel removes metal from the the entire face of a bevel. When the amount of length removed from a tool in either case is considered, it is probably in the realm of three or four zeros after the decimal point.

jtk
Thanks Jim, very good explanation