flattening oil stones?

[Archie England]

I've enjoyed the thread on flattening water stones, because that's what I'm learning on. However, I've inherited and picked up some random oil stones--some light, some dark. Is sandpaper on granite the best way to flatten these?

thanks for the help.

Archie, near NOLA

[Jessica Pierce-LaRose]

I had always heard of flattening oil stones on concrete/cinder blocks or the sidewalk. No idea how well this works. If the stone isn't out of flat, but just overly clogged, I've heard about putting them in a dishwasher or boiling them to get clean them. Again, no idea how well this works.

If I remember correctly, the Norse Woodsmith website has a fair amount of info on oilstones.

[David Weaver]

They will punish the abrasive on most sandpaper.

I have had the best luck with them on a sanding belt for the rough work and a diamond hone to get them dead flat (for ones small enough for that).

I can't recall how much damage and how fast my black stone did to a 3 foot strip of stick down roll, but I didn't finish flattening the whole stone (a large 12x3 stone) that way, so it must not have been going that great. It's too big for my belt sander.

Sometimes the older stones are really nasty out of flat if they were never used for anything other than knives.

If you go the belt sander route, plane on junking the belt and wear a mask.

[george wilson]

DO NOT put your dirty,oily stone in the dish washer,unless you want to be on your hands and knees trying to get the scum out of every nook and cranny!!!!! Needless to say,while under the scrutiny of your UNHAPPY wife!

Flatten your stone on your diamond bench stone,or on a zirconia belt. Recommend gluing the belt down and rubbing the stone on it. A belt sander might throw a bunch of unwanted abrasive dust around.

You probably don't have one,but I taught everyone in the museum to rub their stones on the side of their big sandstone wheels with water. Made quick work of even hard black Arkansas stones. Can you buy a flat piece of sandstone from a local architectural stone supplier? A damaged one would be free or cheap if it couldn't be used in a building. Lay it horizontal,pour on plenty of water.

[Archie England]

Wow! that was close--nearly avoided the disaster of the DW suggestion. Good thing that I had to go to work today. George, would a Delta grind stone (10x2"wide) make an acceptable flattening source?

[george wilson]

Would be O.K.,if it isn't made of the snow white friable (easily worn down to expose new sharp grain) material much used now. You might wear a dip in it,so,be observant if you try it.

[David Weaver]

Wow! that was close--nearly avoided the disaster of the DW suggestion.

?

The belt sander? If you don't like dust in the shop, move it outside. Unless the dishwasher suggestion was being attributed to me, I wouldn't do that, either. I've never found the ones that are loaded to be a real problem, you can always just refresh the surface, and the dishwasher doesn't do anything for flatness.

Heard people talk about boiling them to refresh them, but again, old pot that you use for dirty work.

[Archie England]

Unfortunately, the Delta wheel is the white, more friable type. I've got a 1" gray (36grit?) but it's an 8" wheel. Would that work?

[george wilson]

How large are the stones you want to flatten? The 8" wheel would probably cut them,you can soon find out if it will! But be careful you don't get the stone hollow from having it hang over the edges of the wheel.

The India stones are aluminum oxide based,which is very hard stuff. But,the soft sandstone old fashioned large grinding wheels did cut the black Arkansas stone right down. Give it a try. I don't see how you could hurt anything. Just check the bottom of your stone and the surface of the wheel often,to make sure the wrong one isn't wearing out. Rotate the wheel often,so you don't wear a groove across it.

A zirconia (blue)grinding belt would certainly work if glued down to a flat surface. Can you get them? Can you get a BLUE belt sander belt? Cut it at the seam with some no good(but functional)scissors. Get a 36 grit,or at least an 80 grit. That would give you a much larger surface to rub on.

However,I have not gotten a blue belt sander belt all wet. I use my sandstone wheel. I'm not sure if the abrasive would come loose if wet. Actually years ago I used the sandstone wheel. Now I use a diamond stone followed by black,then white ceramic stones which NEVER EVER need flattening,or unclogging. I went to them in the 1980's,and quit using anything else. In the 60's I used an India and an Arkansas. In the 70's and early 80's,barber's Super Punjab razor hones,which were easy to dress. They weren't real large stones,though,about 3" x 4". I don't know if they are still made. The American Hone Co. made them. Could Google them easy enough,though I am sure the older man who made them is now dead,and the stones could now be made differently.

They had a coarse green side which looked like the green wheels for grinding carbide tools. The other side was a smooth textured tan color. They would not sharpen D2 steel tools I started making in the 80's. The ceramic stones were greatly harder,and sharpened the D2 right up. When I was sharpening carbon steel tools in the Historic area,they worked fine. Razors are plain carbon steel

[Archie England]

Thanks George! I really appreciate being able to benefit from the seasoned knowledge and wisdom.

[Peter Evans]

To clean dirty oilstones place them in a large container of water with a piece of old towel on the bottom. Add some dishwashing liquid and some dishwasher powder - and place on a camping stove outside. Then boil away, turning the stones from time to time. After a while the water gets too dirty, so a new supply.... Continue until clean.

I have also used an old old water urn, with towelling at the bottom - very effective. I have never tried the dishwasher - I don't think my marriage is THAT robust.

Interesting thought to use the side of old, hard, grinder wheels - I must try that.

Cheers
Peter

[Bill Houghton]

I had always heard of flattening oil stones on concrete/cinder blocks or the sidewalk. No idea how well this works.

While it may depend on the quality of the stone, I recently flattened one on a concrete block. The stone in question was a $1 unknown brand, moderately soft; I was getting it ready to loan to a friend who's doing a sweat equity house (the tool list included a chisel, but no sharpening stone...not sure if the group organizing the project thinks chisels never need sharpening or what). Took just a few minutes. I lubricated with water, to wash the swarf away.

[David Keller NC]

Archie - I've successfully flattened several Arkansas stones on aluminum oxide paper on a granite plate. While true that each stone trashed several pieces of 220 grit paper, that wasn't a big deal to me. However, I'd also note that these stones were only slightly out of flat. Way out of flat may well require what George mentioned - a harder abrasive like a zirconium belt. This might also be a good excuse to buy one of DMTs new "stone flattening" diamond stones.

Regarding cleaning - I prefer a much less environmentally friendly method to cleaning old oil stones. I immerse them in laquer thinner. Occasionally, heavy grease on the stones have required a second immersion in kerosene.

[Jessica Pierce-LaRose]

Hey, while I did sort of add the disclaimer that I had now idea how well it worked, I want to apologize for simply passing on second-hand information (of a potentially disastrous type!) that I had only read about without any actual experience. Particularly without pulling up references, that was just irresponsible, and didn't really add to the conversation. I'm glad others were here to steer things the right way. (And I learned a lot from this thread!)

Sorry about that!

[Adam Cherubini]

I flatten my stones using a 120 grit or 180 grit diasharp plate (I have x-coarse and XX-coarse). Works fast. Only issue is, it "grades" the surface like a Tormek wheel, making the stone cut more aggressively than it should. Not a bad idea to polish the stone using a finer grit diamond plate, or rub two stones together. I flatten my stones dry and use an old tooth brush to remove the dust frequently.

I put stones in the dishwasher all the time and don't understand what the issue is. I put all kinds of greasy stuff in there and it comes out clean. George may have had a bad experience with a super oily stone. By all means wipe it down as best you can first. And I don't like flattening oily stones, so new old stones get degreased first.

Selecting the right honing fluid can be tricky. Have a new couple of articles on this subject for PW expected out in Fall. I'll have more stuff on my blog when these mags hit the newsstands. I've been custom shaping old whetstones for use with carving tools and having some success with them. You can cut them with a tile saw and shape them with a belt sander or belt sander belt just as George describes. Works faster than you might think. I'm a big fan of Ouachita (Washita) stones. They really do a great job, much better than India in my opinion. Look out for them. They are light tan when scratched/cleaned but often chocolate brown in the wild (flea market wild, not mountain wild).

Adam