Which way to use a grindstone wheel for chisels?

[Deadeye]

I've seen contradictory advice. Most seem to put the bevel "up" to the wheel so the cutting edge has stone turning towards it.

However, I've seen another source that advocates the other way round - chisel pointing down and the stone rubbing along the bevel towards the cutting adge.

Which is it and why? Is it different for turning chisels and cabinet chisels? Or doesn't it matter a hoot?

 

[worn thumbs]

Cutting edge pointing up.You may well get replies from people advocating grinding on the side of the wheel-ignore them unless you have a grinder and wheel intended to be used in this way.

 

[That would work]

I can't imagine having the chisel pointing down.
As said don't use the side, you can break the wheel which could be uncomfortable.

 

[AESamuel]

I've not known anyone to advocate grinding chisels pointing down.
Moving the edge into the abrasive will mean a smaller burr to deal with (this is true for regular sharpening stones too) so if you're using lathe tools straight off the grinder you will definitely want to the wheel going towards the edge.

 

[nev]

Transpose what you do with a stone or diamond plate.

You push the chisel bevel along the stone with the first edge being the bottom of the chisel.

Apply the chisel to grindstone in the same manner only this time the grindstone is coming to the chisel as opposed to you pushing the chisel to the stone.

 

[AJB Temple]

It is exceedingly dangerous to have the chisel pointing down (the wheel rotating towards you) especially if you have a tool rest fitted to the grindstone. You only need a moment's inattention or distraction for the chisel to catch between the moving wheel and the rest. I have seen this happen. It was not pretty. Wrecked both stone and chisel, and the shaft that holds the stone was bent out of true. Operator claimed he had done it this way for years. Grindstones need treating with respect.

 

[Mike Jordan]

This home made guide is usefull for keeping the grinding angle steady with plane irons and larger chisels. Resting the hand holding the shorter chisels on the rest works for me.
The other tool shown is used to break the glaze and expose fresh abrasive on the edge of the stone. The stone is moving down on the outer edge. I use the safety screen and separate eye protection .

 

[stuckinthemud]

I tried a variety of ways to grind chisels using bench grinders and the best way I found was to reverse the direction of the wheels by taking the whole of the top (motor and wheels) off the switch box/stand and turning it around. This sends the sparks upwards so you need extra care and face protection is essential BUT it is now working the best way for sharpening chisels and gouges. Fit it with a rubber disk and float chrome polish on it - no sparks just a face full of gunk, if your clumsy. Now you can see the chisel edge being polished away, especially if the edge is lit properly with a strong light directly above it - you can see the shadow between the bevel and wheel slowly disappearing. I ground my chisels and gouges this way for years. Hone them on a slip stone or leather strop loaded with chrome polish. Now though I use a belt-sander with a medium or fine belt for the grinding, I find it much superior to a grinding wheel set-up. You should be honing the edge of a chisel every 10 minutes of use or when you feel the edge is failing - for instance when wood curls are sticking to the blade instead of releasing cleanly - using a slip or strop, do this and you'll never need to use the bench grinder. Last time I needed to resort to a grinder was last May when I dropped a chisel (AARGH) and needed to grind out the damage

 

[D_W]

Transpose what you do with a stone or diamond plate.

You push the chisel bevel along the stone with the first edge being the bottom of the chisel.

Apply the chisel to grindstone in the same manner only this time the grindstone is coming to the chisel as opposed to you pushing the chisel to the stone.

This isn't universally true - sharpening edge into an abrasive is good policy if the abrasive allows (less or no wire edge on final honing), but that's not that important here.

From a mechanical standpoint with the OP, the tail end of the grind will be hotter. There's no good reason to subject the edge to trailing heat, especially as most machines are designed for an edge first grind - slipping the bevel of a tool against a rest going downwards could be disastrous (all the way up to a fracturing abrasive wheel - lost eyes or worse are possible).

The only commonly used trailing wheels that I can think of are the giant wet wheels used to manufacture japanese tools.

 

[--Tom--]

Tormek’s allow edge leading or edge trailing. Their details say edge leading is more aggressive and edge trailing better for finishing.

I have a creusen grinder that runs in reverse that was cheap off the bay, plan was to put a felt wheel on it for power stropping but not gotten round to it yet.

 

[nev]

Transpose what you do with a stone or diamond plate.

You push the chisel bevel along the stone with the first edge being the bottom of the chisel.

Apply the chisel to grindstone in the same manner only this time the grindstone is coming to the chisel as opposed to you pushing the chisel to the stone.

This isn't universally true - sharpening edge into an abrasive is good policy if the abrasive allows (less or no wire edge on final honing), but that's not that important here.

From a mechanical standpoint with the OP, the tail end of the grind will be hotter. There's no good reason to subject the edge to trailing heat, especially as most machines are designed for an edge first grind - slipping the bevel of a tool against a rest going downwards could be disastrous (all the way up to a fracturing abrasive wheel - lost eyes or worse are possible).

The only commonly used trailing wheels that I can think of are the giant wet wheels used to manufacture japanese tools.

Sorry. I'll rephrase.

Disclaimer: I don't spend my life dissecting the incrises of metallurgy and sharpening to the nth degree. I merely sharpen a chisel by pushing it along a stone or if its a gouge for turning I use the grinder.

Most normal users of a chisel will sharpen it by pushing it along a stone. Offering it up to a wheel at the same angle with the wheel rotating (down) towards the chisel will perform the same action only the the stone is now moving as opposed to the chisel.

 

[MikeG.]

.....Most normal users of a chisel will sharpen it by pushing it along a stone....

Really? I don't. I want to pull the waste (the burr) off the edge. I'm wondering where you got the idea that most do it the other way. I'm sure you wouldn't be suggesting that those that do aren't normal.

 

[nev]

.....Most normal users of a chisel will sharpen it by pushing it along a stone....

Really? I don't. I want to pull the waste (the burr) off the edge. I'm wondering where you got the idea that most do it the other way. I'm sure you wouldn't be suggesting that those that do aren't normal.

Fair enough, I'm an imbecile. Please ignore what I say.

 

[TheTiddles]

Depends how the grinder is configured, in industrial applications you get both, the pressure angle varying depending on how aggressive you want to cut and how well supported the workpiece is.

As noted, Tormeks go the other way and they seem to work ok, but they’re also not intended for aggressive material removal, a bench grinder is more so and as most of us know, pretty useless for finely grinding your bench chisels, but just about fine for your turning tools, due to a number of factors, but the two big ones are in the first paragraph

Aidan

 

[MikeG.]

.......Fair enough, I'm an imbecile. Please ignore what I say.

No you're not. And no, I won't. I'm actually curious as to whether pushing really is the norm.

 

[AJB Temple]

Worth pointing out that comparisons with Japanese grinding wheels in Japan (at least the ones I used in my few weeks of knife making courses) were a) enormous (usually about a metre diameter) b) ran very slowly in a large water bath (think cattle trough) and c) could be reversed. My memory may be playing tricks, but I don't think the ones I was taught to use had a tool rest at all.

The Tormeks (and copies) also run quite slowly. I have a couple of grindstones in my workshop and they both run at high speed (one is actually a polishing station). The one I saw where the operator got the tool stuck between the wheel and the rest, was similar. Seeing a blade get stuck and then the resulting chaos was both an eye opener and quite possibly an eye closer for the operator.

Grindstones are usually pretty harsh for sharpening - at least in my inept hands, so I prefer to use a linisher.

I will recount briefly my first every grindstone experience. My secondary school was a streamed grammar school. The top tier kids had to do academic stuff, but we were allowed to do metal work and woodwork in lunchtime classes, which I loved. Only for 2 years. The metalwork teacher was a fantastic bloke called Mr Grimes and the grinder was outside his little office. It was running one day (I think we were being taught heat treating, annealing etc and had to produce an edge) the machine was switched off but running down having just been used. Some extra risk averse kid 8) leant on the machine. By the time the teacher realised, the machine had ground through his arm down to the bone. He didn't feel a thing. At first.

Brilliant lesson for me seeing this - I have been respectful of machinery ever since as I did not want that sort of thing to happen to me.

Be safe, ladies and gents.

 

[Phil Pascoe]

I don't think I've ever seen anyone ONLY pull them, except on a strop.

 

[TheTiddles]

As mentioned, grinding stones are as dangerous as any other power tool, I saw a small bench grinder in a factory once break a stone, gave the guy using it a bit of a jump, the horrifying bit was the light fitting on the other side of the factory shattering about a second later, must have been 40’ away and hanging 20’ in the air, glass and powder all over the laying out table.

Just to muddy the waters a bit more... grinding, linishing, polishing, lapping and honing are all the same process (sacrificial abrasive particulate), just different ways of implementing it. A good grind can be far finer than a course lap, a sub-micron hone can produce as wobbly and useless an edge as you’ve ever seen.

Aidan

 

[worn thumbs]

I remember that back in the eighties a few excerpts of Ashley Iles autobiography appeared in the Woodworker.One issue focused on the work done by the grinders in the Sheffield cutlery industry and they didn't just grind bevels on one sort of implement,they did whatever came in the doors.He described the way they worked with wheels that rotated away from them and that they ran them really fast-I seem to remember twice the speed recommended and maybe somebody who has a copy of the book to hand could verify that.One of the reasons for running the wheels very fast was that like all the other independent specialists they were paid piecework and had every reason to get on with the work.My memory also tells me there was a mention of the records showing that few of them reached their 35th birthday.

 

[D_W]

Worth pointing out that comparisons with Japanese grinding wheels in Japan (at least the ones I used in my few weeks of knife making courses) were a) enormous (usually about a metre diameter) b) ran very slowly in a large water bath (think cattle trough) and c) could be reversed. My memory may be playing tricks, but I don't think the ones I was taught to use had a tool rest at ...

Yes, completely different animal. Wet, big and fast. Instead of having a rest, heavy grinding is undertaken with a tool in a larger fixture.