Handplane Issue - No.4

[AndyT]

Thank you, good to know! Is there a risk of shattered / internally cracked wheels with old grinders? I just didn't want abrasive bits flying towards me

The problem is if some previous owner worked too hard on the side of a wheel that was designed only for use on the edge. Try gently knocking the wheel with a bolt or something. If the wheel rings with a nice clear sound, it's ok. If it sounds dull, inspect the wheel closely then replace it. (Compare the sound from both wheels while you still have them on.)

And don't be tempted to remove the metal guards shrouding most of the wheel.

 

[jeremyduncombe]

Bp122 wrote:
Is there a risk of shattered / internally cracked wheels with old grinders? I just didn't want abrasive bits flying toward me [/quote]

A mate of mine is a skilled and generally safety conscious antique restorer. A few years ago he was using his bench grindstone for some purpose. He lifted his face mask as soon as he had switched the machine off, but while the wheel was still spinning. The wheel ( which was old and well used ) disintegrated and a chunk passed through his jaw from one side to the other. His jaw was rebuilt and he now wears dentures. If you did not know him before the accident, you would not notice anything wrong with his face - but I am now super careful with any grinding wheels. A one-in-a-million chance I guess .... but you never know.

 

[jeremyduncombe]

Apologies for that rather depressing post. Grinding wheels are useful tools and it has not stopped him or me from using one.

 

[D_W]

This reminds me of model airplaning here in the states, as well as grinders. You can use a grinder without standing in the arc, which isn't bad policy for a beginner. I've been to the ER once (from a low speed belt sander of all things - it had just enough speed to toss a round metal particle onto the surface of my eye - I thought I could stand off to the side and get away with it "just once" and didn't even feel it, but looking in the mirror at the end of a shop session saw a shiny little dot in the brown of my eye - it wasn't but a day or two of hassle to get it out and then deal with an eye that had been numbed and dilated to the moon during the process).

I never work without glasses now (grinding hammering anything). I never push hard on the side of a hard wheel, and I don't stand in the arc of a wheel in heavy use. My "injury" was at low speed, just a nuisance. But a good lesson to think about what can happen at high speed. Your friend's is a good reminder, too.

An English friend of mine likes to say "The difference between the Rockefellers and the Smiths is that the Rockefellers got where they are by being smart enough to learn from other peoples mistakes rather than insisting on making them themselves".

 

[Cheshirechappie]

Couple of quick points about grinding wheel dressing.

First point is that it's a process that generates a LOT of abrasive dust, even if you just skim the periphery of the wheel to clean it up. Best done outdoors, or at any rate, well away from anything that might not like the dust. That, or cover things over beforehand, and clean up thoroughly afterwards.

Second point is a tip from Barry Iles (one of Ashley Iles' sons, and currently on of the owners of that firm), who learned his trade as a young man from the Sheffield cutlers and edge-tool makers. Dress the periphery of the wheel to a very slight crown, and when grinding, keep the tool moving side to side. That will practically eliminate the chances of over-heating the tool.

 

[D_W]

Most of the dust settles below or behind the grinder. I think (I've never measured) that my grinder is probably about 6 feet from the butt end of my bench, and tucked into a corner next to a built in cabinet in an attempt to limit where the dust goes. I've never had any issue with contamination on my bench (and I still do heavy tool grinding on a harder brown wheel, even though regular grinding of hardened steel is now done on CBN).

I can say this, though - anything remotely close to being beside, behind or under the grinder will be absolutely filthy and coated. I can vacuum a lateral swath below the grinder, behind it and under it and literally see enough filth to make the floor hard to see if I have been making tools or when I used to bring old ones back up to spec. You do sort of have to give up that space for the grinder, but anything more than a few feet away in front of the grinder won't suffer any issues.

 

[Bm101]

Second point is a tip from Barry Iles (one of Ashley Iles' sons, and currently on of the owners of that firm), who learned his trade as a young man from the Sheffield cutlers and edge-tool makers. Dress the periphery of the wheel to a very slight crown, and when grinding, keep the tool moving side to side. That will practically eliminate the chances of over-heating the tool.

Clear this up for me please Mr C. I can't picture it.
By crowning the wheel are you reducing the amount of steel in contact with the wheel? Like skewing a plane iron in the cut? You are grinding on a point so to speak.
I don't doubt it's true. Just trying to understand it.
Sorry for being slow....
(homer)

 

[D_W]

What he's saying is correct. You get a point of contact and the blade gets intense heat production on that point for a second, but you don't stay on it long enough for it to matter. Faffing with a flat wheel that's not CBN is a good distraction to allow for heat build up, and your bevel may not be hot half of the way across a flat stone, but it could be by the time it gets to the far edge.

The crowned wheel also gives you much more control to rotate irons and chisels, etc, when the iron may not have ideal geometry (or the rest setup isn't perfect). On a flat wheel, you end up working the iron or chisel on one edge or the other doing that, but sometimes losing control of which edge you're on and inducing a burn.

I probably couldn't explain all of the ways its better verbally (especially being the man of few words that i am ), but for touch and craftsman's sense (things that we do that are hard to put in words) the crowned wheel is much nicer for day to day bevel grinding.

 

[bp122]

Sorry for being slow....
(homer)

Something was said... Not good... (homer) (homer) (homer)

 

[Bm101]

Thanks David. Enough to know I have it right.
Cheers. Good tip! Thanks Mr C.

@BP. sometimes even I'm surprised I made it this far.
:wink:

 

[D_W]

The same tip was popularized in the states by Joel Moskowitz.

But it came from the same place - he sells Iles tools and iles showed it to him. I couldn't tell anyone the last time I actually burned a tool on a brown al-ox wheel, and that's hundreds (or more) bevel grinds before going to CBN. I don't keep water at the grinder either, but you have to be perceptive to do that.

What I do to prevent burning is the following. Light pass across the wheel, pull the tool across the palm of your off hand. if you're afraid it's really hot, pull it fast across. The slower you can pull it, the cooler it is. If you can't do that, the tool is too hot. Even doing this, the refresh is not more than a minute at the grinder, and it's only every 5 hones or so.

 

[Cheshirechappie]

To be absolutely truthful, Chris, I haven't seen a detailed explanation of how an why it works, I just posted it on the basis that if it's good enough for the Iles brothers, it's good enough for me!

That said, a couple of things do occur. A very slight crown will reduce the chances of a wheel corner nicking a long edge (happened to me once regrinding a drawknife on the Tormek - boy, did that nick take some dressing out!). Also, it means the grinding action is concentrated nearer the middle of the wheel on a small area, which, because you're traversing the tool, comes into contact and then out again quite quickly. Thus, the bit that's been in contact (and heated) gets a chance to cool again before it's next contact, which is also brief.

You'd think this would slow the overall grinding process down, but it doesn't seem to. It's as if the small contact area does the work that the whole wheel width would do if in contact. The small area cuts a bit deeper than if all the particles across the whole wheel width were in contact, each cutting shallow, rather like a plough iron will take a thicker shaving than a try plane iron does in facing a board.

Sorry that's all a bit conjectural. As I say, not sure in detail exactly why it works, but I know it does.

 

[Cheshirechappie]

The same tip was popularized in the states by Joel Moskowitz.

But it came from the same place - he sells Iles tools and iles showed it to him.

That's where I got the tip from, too. I was going to put it in my original comment, but it just seemed like too much verbal padding for that post, TBH.

To be more specific - Joel's Blog on the Tools For Working Wood website, which is well worth a perusal (the blog, and the website).

 

[Bm101]

T

Sorry that's all a bit conjectural. As I say, not sure in detail exactly why it works, but I know it does.

No. Not at all.
It makes sense. Can't explain it either. Some things are just self intuitive I suppose.
I went to a bbq many years ago. Was running late due to work etc. Got a phone call from the host. Have you left yet? Erm no.
Ahh. Err. Could you being some fire starting tools?
Wheelll ok then.
I turned up and there was 12 -15 bearded males trying to start a fire with newspaper and logs.
Alright chaps I said.
Stand back I'm about to blow your minds and make you more attractive to women in one step.
Look. This sh* is called kindling....

Oh. Ohhh! I've heard of that!!!said Brian excitedly from the marketing dept of some company.
Hopping on one foot with his hand in the air. Not kidding.

:|

 

[WideningGyre]

If one is using a diamond dressing tool wider than the grinding wheel, and most are, it's pretty hard NOT to crown the wheel a little when dressing it.