Agitating on recommended grinders...

The shorter point...

David Weaver

in mentioning this little experiment is that the advice to avoid heat build up is often tilted toward strategies that aren't that cheap or practical (especially if you're restoring old tools to get yourself started or making your own tools).

* wet wheels

* variable speed grinders

* CBN

* seeded gel

And whatever else.

The ability to avoid much heat grinding is as simple as a cheap grinder, a cheap hard coarse wheel and an inexpensive T shaped diamond truing tool.

(I put no crown on the 24 grit wheel, either - that would be undesirable when it comes to tool making).

Re: Agitating on recommended grinders...

Jack Dover

There's definitely a dependency between heat generated and the amount of material removed. The finer the wheel the slower the removal rate, so finer wheels heat a tool more. However, a coarse wheel might leave scratches so deep that polishing them out removes a hollow (I have such a wheel), so even when hollow grinding is not considered, you're just correcting an edge on a grinder and a majority of sharpening still happens on relatively slow stones.

So maybe that's why most recommendations for a wheel are for 80-100 grit range: not too hot and metal is not removed too fast, so a user has more control. And maybe experienced users go with coarce grits because they have better wheels, more skills, etc.

Probably a recommendation for a grinder should be "anything that's balanced and doesn't try to walk out of a shop". Unfortunately this is something really hard to check at the store. And most of the grinders are junk not because they can't spin a wheel, but because of overall low quality of manufacturing.

Re: Agitating on recommended grinders...

David Weaver

My rule for balance now (because even wheel balancers, etc, don't always cure everything with some wheels) is a grinder that doesn't walk once it's bolted to something.

AS far as scratch depth, I used a 46 grit pink wheel before going to the 80 grit CBN wheel. I was shocked at first that the grooves from the CBN were monstrously deeper, but when it was fresh like that, it definitely ground very cool. The grooves were deep enough that if they got to the edge, the first honed edge would be kind of trashy (unexpected chipping).

The 24 grit scratches are coarse, but not as coarse as the fresh 80 grit CBN wheel, and nowhere close to the scratches that a 36 grit ceramic belt leaves. Why the belt is so coarse, I don't know, but it's a destroyer.

Picture is from the 24 grit wheel. Very usable - 36 grit belt grinder, not usable, but the point of those belts is to grind large flat surfaces like large knives (the abrasives are arranged almost in piles, too, which exacerbates things).

Re: Agitating on recommended grinders...

Bill Tindall, E.Tn.

It would seem that this experience is focused toward anyone with a need to hog off lots of metal. I am using a 120 grit pink wheel for sharpening. For a long time I ran it slow for control of the metal removal. ( I run it 3600 rpm now that I am more experienced.) But rate of material removal has never been my concern. Controlling metal going away was the concern, especially as I neared the tip. My point is that this wheel may not be the best for someone just grinding to restore a hollow, and maybe not experienced with grinding at that.

What is the bond letter of your new wheel? Actually what is the total wheel description so the details of the abrasive particle are known as well?

In this case...

David Weaver

..this wheel is actually excellent for restoring a hollow, it doesn't cut as deep as the grit would suggest and it will cut as slow as you want if you don't apply pressure.

Fewer sparks, but bigger ones.

As far as what the wheel says, it doesn't say anything useful on it in terms of the long string of typical letters. On the front side, it has safety warnings, and on the back side, it just says A4024

If any of the verbiage indicated brand, I don't know what it was and just put it back on without thinking that I should take a picture.

Strangely, there is nothing useful on any of the wheels that came with the grinder other than max speed. They say "A60" and "A36" on them and that's it.

(mcmaster part 4463A424 - that also doesn't provide much useful information that I can see). Fairly cheap, but there's a difference in weight between the 36 and the 24 (the matrix on the coarse wheel is more open). it sheds particles, too and heavy work will wear it visibly (not bevel refreshing). I like it much better than any of the other wheels I've had for refreshing bevels with the exception of the CBN.

stunning turn for the CBN

David Weaver

OK, not that stunning. Years ago, the wheel was slow, and I decided to use an abrasive rubber on the wheel (rubber, not abrasive, but for abrasive belts, etc). It cleaned the wheel off and made it like 80% of new again.

It's slow now and will burn AEB-L and V11 if you're not careful, but I just went out and tried the rubber again. Little change. I decided to scrub it hard with a grill brush style wire brush in case what's stuck to it is resistant to something like a rubber, and it did greatly refresh the wheel and cut back on the heat. It's no about half as fast as new, and cool grinding again (relatively cool), so that's a great improvement.

No clue what the thin layer was (it came off as dust when brushed, but didn't come off with the rubber).

The A24 wheel is still a lot faster working. The virtue of a 24 grit wheel like I'm comparing is that in 6" size, they're $17 at mcmaster carr. just under $30 for an 8x1 wheel.

Scratches

Jack Dover

That looks okay to me. I don't have lots of experience with grinding wheels, the one that is scratchy came with a grinder. It's also badly out of balance, I just assume it's a low quality wheel. Removed it because it feels like it's going to shatter any moment and because it's bad for bearings.

EDIT:

Bolting a grinder down will keep in place, however walking is a symptom, not a problem. I used to have access to a Baldor grinder (had no idea what is Baldor at that time), it was screwed to a flimsy bench top. A water in a can next to it was absolutely smooth and motionless. My current grinder is a new Delta, it's bolted down and even after many hours of dressing and centering a wheel water in a can on that table shows this nice waves interference picture, could be a textbook illustration. I don't think it will be more than a couple years before bearings will die. Maybe it doesn't affect grinding, but it's so much nicer to stand next to a smooth and quiet grinder that doesn't sound like a helicopter taking off.

the culprit on my baldor

David Weaver

is probably the brown wheel (one that was about $14 from mcmaster, so a cheapie - but good enough to have bushings in the center instead of a rough sized hole).

I never put the baldor on a surface unfastened, but it's 40 pounds and probably wouldn't walk. It's not like a heavy pounder, rather a vibrating kind of thing and minor.

Interestingly, The CBN wheel will collect junk around its rim unevenly (metal dust cake) and needs to have that stuff scuffed out sometimes.

The heavy taiwanese jet grinder is very smooth, even with cheap wheels, but the wheels do need truing sometimes. They must vary in hardness (i know some cheapies vary in density, so you can true them and they'll still pound) or some other cause as heavy grinding will create a wheel that's slightly out of round after a while. When a wheel is out of round, as you're aware, it'll pound on something and only cut through an arc that's a fraction of the wheel. It seems to me that this should be a self correcting thing, but it never seems to to me.

Has anyone tried CBN wheel on a tormek?

Jerome

Grinders, wheels, CBN, ... Great, I had a question about this. My tormek wheel is getting small and I was wondering if the CBN wheels from wood turners wonders were that interesting.

I mostly use my tormek to restore my planes and chisels bevels true and hollow, so coarse only. I sharpen and hone on stones and strop.

It’s a slow machine but I really appreciate how quiet it operates compared to a grinder, and the jigs are good. And I already paid it, that’s a plus. On the other hand, water can be messy and truing the stone make my neighbors dogs go crazy

WTW wheels for tormek only go down to 200 grit. Is that worth 200usd compared to the standard 100usd sg-200 for coarse grinding?

paging wiley!!

Re: Has anyone tried CBN wheel on a tormek?

Wiley Horne

Hi Jerome.

I strongly encourage you to put the WTW CBN wheel on your Tormek. It makes a new and different machine of it. I took Derek’s CBN advice and have never regretted it. The 200g wheel is the one for grinding—I grind to a new burr, then follow with stones—1000, 2000, 13000 Sigma—for honing. Then buff.

The CBN wheel is faster on the Tormek than anything else you’ve had mounted, and it’s cool working. One of the things you’ll appreciate most is removing the water tray, and always working dry. You’ll forget the $200.

It grinds everything with no problem—from straight high carbon to CPM-3V and M2.

Here is the set-up—pardon the dirt:

I recently bought another leather wheel. The older one, impregnated with Tormek paste, I just found useless. This bare leather one is very useful for buffing after honing.

This CBN wheel (10”) I bought off Ebay from WTW, rather than off the website. Saved maybe $20 doing it that way.

Be glad to answer any questions.

Wiley

Has anyone tried CBN wheel on a tormek?

Tom Colligan

Wiley, do you now use nothing on the leather wheel?

And, what is a source for 8" leather wheels?

Thx., Tom.

Re: Has anyone tried CBN wheel on a tormek?

Wiley Horne

Hi Tom,

The 10” leather wheel is Tormek item LA-220. I bought this one for $80 delivered, on Amazon. Noticed the same price w/delivery on Ebay. I tend to use Amazon because if anything goes wrong, they make right fast.

When I ordered the wheel.my plan was to put a light smattering of 1-micron green paste on it. But when it arrived, I was honing my pocket knife (1095 blade). and tried the bare leather after honing. Wow! Liked it enough to just leave it as is.

Wiley

Correction—oops

Wiley Horne

Tom,

I said 10” leather wheel—there’s no such thing. It measures 8-1/2” (approx.), and is the right size for T-7, T-8, and 2000 machines.

Wiley

Re: Has anyone tried CBN wheel on a tormek?

Jerome

Thanks Wiley for this feedback.

I have no doubt that CBN wheels would be beneficial regarding water mess and keeping it true but it’s great to hear that the 200 stone is faster than the default wheel too.

Re: Larry wrote about these

Steve Voigt

24 grit wheels aren't mentioned often in the woodworking community

Agree that few have mentioned these wheels, but Larry used to mention them on forums, and there's this Instagram post:

https://www.instagram.com/p/8wsrfPQNwJ/

For those who don't want to read the post, the wheel is labeled A 24 Q 8 V.

Larry writes: "This is the best grinding wheel I've found for our purposes. It has a relatively open structure and isn't too hard or too soft. It's also a coarse 24 grit. We get them from www.victornet.com. The 6" x 3/4" wheel sells for $8.40 if I remember right but they have a minimum order of $30 or something similar. If one is accustomed to a dense spark pattern they may think this wheel isn't removing anything but it grinds so cool there isn't a normal spark pattern."

I have not tried those wheels, for no reason other than inertia…I'll get off my ass and order one today.

Re: Larry wrote about these

David Weaver

similar comments, except mine makes a big spark pattern.....I think the open matrix on them and large grit makes it so that they are probably technically a hard wheel, but the big bits and holes come apart easier.

The sparks are fewer but much larger. Sort of like comparing a string of little mini christmas lights to a string of fewer of the old 7 watt bulb types. Something slightly different in mcmaster's wheels vs. the ones at victor, maybe - mine

If they're relatively cool running on a high speed 8" grinder, they should be easier yet on a 6" machine.

Not that you can't burn an edge with them on the high speed 8 if you lean into them, but there's no need to do that (the same is true for CBN - my first ever test with the CBN Wheel was to flip the bevel on a 1/2" timber mortising chisel that someone had on the wrong side of the tool - it was bright orange by the time I ground off a triangle with a base length of over an inch. and the CBN wheel held up fine (which was what I was really looking to test).

Decoding

Bill Tindall, E.Tn.

A 24 Q 8 V.

A is aluminum oxide

24 grit

Q hardness that's hard!

8 V something to do with the particle structure specific to the manufacturer of this wheel

Re: Larry wrote about these

Steve Voigt

Dave, where did you get your wheel? I looked at the ones from Victornet but it says "24 grit (C)" and I can't figure out what the C is for.

https://www.victornet.com/detail/GWBE-8-1-C.html

McMaster Carr...

David Weaver

....just the "regular" wheels.

Like bill said, the tool room general purpose wheels probably all have a hard rating (the 46 grit wheel that I got was N, I believe, it's norton - but this coarser wheel has minimal marking).

There is a friable option that's silicon carbide, but these already shed particles in annealed steel, so there's no good reason to get something even more fast wearing.

I think, responding also to bill's post, that I'd guess my wheel as an M or N hardness (a complete wild guess), but it's the open nature and lower density with bigger particles that makes it seem like a less hard wheel.

Very noticeable even between the 24 and 36 wheels - big weight difference that probably makes even a high hardness wheel have less conviction holding its particles because they aren't as closely packed to protect each other).