I've been thinking about that old post from Ionut about grading the wheel (carefully) with no water in the tray
I haven't tried it myself yet.
In a similar vain.....
Suppose you wanted to take loads of metal off during a shaping operation, couldn't you grind dry for short bursts....only thinking out loud and haven't tried it. I guess there would be no cooling and no swarf removal, so there wouldn't be any point right?
Somehow though, intuitively, it seems like it would be more aggressive?
Rob
Seems to me like the wheel is much more aggressive when it's dry.
Thanks for asking that again, because I have the same question just from a different perspective.
Can you treat the Tormek just like a regular bench grinder? Just grind away, wet or dry, like grind a broken screwdriver tip back to square without fear of damaging the wheel surface?
It is after all, a (expensive) grinder! Or maybe this sort of a care and feeding of a water wheel question.
Yeah that's kind of what was occurring to me. If it was dry would it be more like a regular bench grinder only slower.
Maybe the adhesives used in the wheel are not designed to withstand the higher temperatures generated by dry grinding considering that it is a water cooled system and not expected to have high wheel surface temperatures?
This may be heresy, so I hope the Norse God of Sharpening, Thormek, will not strike me dead:
I remember a post several years ago where the guy took the wheel from his dry grinder and put it on his Tormek. As I recall, he ran it wet. He claimed very good results. I wondered what the results would have been if instead of the cheap wheel from his dry grinder he had used a Norton 3X 46 grit eight inch diameter wheel.
I have not tried this. It would require some spacers to match the two inch thickness of the Tormek wheel. Nylon spacers or washers might work.
The coarse grit of this combination might be dangerous. I don't recommend it, and I especially don't recommend beginning with the stone revolving into the blade.
anonymous
If you want to use the Tormek jigs for high speed dry grinding there's a mounting kit for that purpose.
http://tormek.com/international/en/accessories/other-accessories/bgm-100-bench-grinder-mounting-set/
I can confirm that grinding anything on the dry Tormek wheel heats up amazingly fast. I needed to remove a small nick from a "home repair" chisel (not one of my woodworking chisels) and thought I'd try it. I nearly burned my finger, barely more than touching the steel to the stone. Water is a lubricant after all...
Interesting. Thanks Mike
And Herman I was aware of the jig converter tool but thanks anyway
Rob
No water, no ground metal removal. Loading of the wheel creates a surface that contacts the grindee and makes it heat up faster because it is full of ground metal filings. I think!
That's what I postulated when I was thinking about it but surely isn't that also true for a regular grindstone? I appreciate regular is much faster, I'm just not really sure. I mean would the only reason a regular grindstone not clog with metal be due to its speed?
On second thought since you ask that, who said that they don't clog? I was purely guessing. Since they heat up so much when dry and fast, I think that is mostly the friction from the contact that does it. Even your hands heat up with just a little rubbing. Forget about the metal loading, it is just plain rotational friction.
I guess it's like Herman and Ken say, if one really wants to get the combined benefit of repeatable tool control with the Tormek jigs and fast steel removal with a conventional grinder then the BGM 100 and a regular grinder is the solution.
You just can't expect the Tormek to do everything
I've got one other question, how on earth do you stop the steel from losing its temper on a dry grinder? I have very little experience on dry bench grinders because before my Tormek I did everything by hand
Two things help prevent overheating the tool in a dry grinder:
The right wheel. My favorite is a Norton 3X. I am partial to the 46 grit. (Use a coarse wheel and a light touch.) The bonding is designed to break down easily and expose fresh grains.
The second key factor is to dress the wheel with a crown. Keeping the wheel flat means more rubbing. If you are trying to start a fire, this is a good thing. If you want to keep your tools cool, a crown is the way to go.
Actually, the ideal solution is a Tormek. (You already knew that, right? :) )
Ken
I love the Tormek Ken....that's beyond question. I'm just exploring options for really fast shaping. Having said all this I still haven't installed the blackstone yet. Actually I've got two hours to kill. I need to try a new fingernail grind on one of my bowl gouges I think ill go give it a whirl. Only trouble is its currently 4 deg centigrade (about what 40F ) in my workshop.
Still I'm gunna have a go
A dry grinding wheel needs to be dressed periodically to keep it cutting well. This is very noticeable when using a chainsaw chain grinder although I notice it on the bench grinder as well.
Ken, I am not familiar with the Norton wheel. I'll have to give it a try when mine wears away.
Quote from: Rob on February 25, 2013, 03:54:10 PM
I've got one other question, how on earth do you stop the steel from losing its temper on a dry grinder? I have very little experience on dry bench grinders because before my Tormek I did everything by hand.
First of all, avoid grinding on places where the steel is thin. If you have to do that use a wet grinder. Like the Tormek. :-)
Second, keep a can of water nearby. Keep the steel cool by dipping it in the water frequently. Never let it get hot.
Well stated, Herman. When I ground off the decades of accumulated mushrooming from the splitting wedges, there was plenty of metal to absorb the heat. A very good recommendation for sharp edges like planes and chisels is to stop grinding when you reach a small flat edge. Finish the rest with an oil or water stone. Often it's that last pass which ruins the edge, just like the last tap with the hammer or the last bit of tightening on a bolt.
Ken
Thanks chaps :)
Guys, my computer has been down for a couple of days, so I'm catching up, but...
DON'T DO IT!!!
It will damage your grindstone and will not have the desired effect (faster cutting).
Take a trip to a machine shop. If they have high end equipment, you'll see that it all uses a liquid coolant. Coolant makes for faster cutting, not slower. Dry cutting on dry grinders is faster because the stones are 4 to 6 times coarser, not because it's dry.
Ah there you are Jeff. I figured up you might be on holiday
Right then....important tip...don't dry grind. Thanks for that
Ken,
Been kicking this grinding wheel thing around. Jeff, this is for the bench grinder, not the Tormek. :)
How durable is the Norton 3x 46 grit wheel? It seems to be pretty hefty on the price.
http://www.woodcraft.com/product/2081178/30614/6-x-34-x-1-norton-3x-grinding-wheel-46-grit.aspx
According to Ron Hock's The Perfect Edge this is the most expensive and the best of the three types readily available. These are called "seeded gel" because the abrasive is embedded in a gel. These wheels run the coolest of the three types (all designed to grind tool steel) but can still overheat.
Interesting. I haven't checked the price of regular bench grinder wheels for years. I'm sure they have jumped significantly in price from then.
There are less expensive options, but they run hotter.
Elden,
I really like the Norton 3X 46 grit wheel on my dry grinder. Before I added it, I was using a Norton white wheel with 80 grit. It was quite an improvement over the regular gray wheels. It has not been used since I added the Tormek.
When I have heavy grinding to do, the Norton 3X does the job. How does it hold up? I have not noticed a problem with it, but that's very unscientific. I hold up better with it because it cuts so well. I would not use it instead of the cooler wet wheel Tormek. For removing decades of mushrooming on a couple splitting wedges, it was a trooper.
If you are in a hurry shaping turning tools and use a dry grinder, that's the wheel I would use. (I have not tried it for that.)
If I was using it for any edges where I was concerned about overheating, I would dress the edge crowned, to narrow the actual cutting area. (Joel Moskowitz' suggestion).
Ken
Thanks Ken! That satisfied my curousity. If you have not noticed it holding up as well, then there shouldn't be too much difference from the standard wheels.
Quote from: Ken S on March 11, 2013, 09:18:28 PM
I would not use it instead of the cooler wet wheel Tormek. For removing decades of mushrooming on a couple splitting wedges, it was a trooper.
No, I'm not trying to replace the the Tormek wet wheel, but have need of the brute force of the bench grinder from time to time. I also have some drill bits larger than 3/4 inch that I sharpen on the bench grinder.
Elden,
I think the #X 46 grit wheel would be just the ticket for large drill bits. The large grit runs cooler than finer grits. It works quickly, and, with a light touch, leaves a surprisingly smooth surface.
(You might want to try using a final freehand smoothing pass with the Tormek.) Keep us posted!
Ken
Poor Jeff. He must have thought the Tormek world went to hell in a hand basket while his computer was down.
Probably won't happen for a while. My wife might string me up! She keeps telling me that I am going to have to cut back as our last at home son, leaves for college next year. ;)