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Short stints of dry grinding.....is it possible?

Started by Rob, February 24, 2013, 05:46:44 PM

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Rob

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
Best.    Rob.

grepper

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.

Rob

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.

Best.    Rob.

grepper

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?

Ken S

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

Herman Trivilino

#5
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/
Origin: Big Bang

Mike Fairleigh

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...
Mike

"If I had 8 hours to chop down a tree, I'd spend 7 sharpening my axe."  --Abraham Lincoln

Rob

Interesting. Thanks Mike

And Herman I was aware of the jig converter tool but thanks anyway

Rob
Best.    Rob.

jeffs55

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!
You can use less of more but you cannot make more of less.

Rob

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?
Best.    Rob.

jeffs55

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.
You can use less of more but you cannot make more of less.

Rob

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
Best.    Rob.

Ken S

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

Rob

#13
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
Best.    Rob.

Elden

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.
Elden