Flattening sharpening stones?

[rich pierce]

Is it possible/worthwhile to flatten old worn sharpening stones?  I have some that are plenty thick but no longer flat from sharpening knives and the way I approach sharpening a curved belly.  Any handy hints?

[Jim Filipski]

Rich,
I have fixed a number of old stones by taking them outside & rubbing them on the concrete side walk  ( takes a long time- better if you have a beer or two beside you) Then I finish them up on a belt sander
Not sure if this is a good way but it works!
Jim

[J.D.]

Are the bottom side of the stones flat? I know the idea of flipping stones over is rather simplistic, but sometimes, in those senior moments,  even the most simplistic idea is not readily apparent. 

I seem to remember reading, though I have not tried it, that grinding on a course grinding belt will flatten a stone. Finish with finer grit belts.

[George F.]

What Kind of stones?  The Arkansas stones are harder than the Japanese Water Stones, which I have flattened on a 12" disc sander, was kind of easy really. I de-glaze Arkansas stones by rubbing them either together or on a diamond plate, which I use now. ... Geo.

[rich pierce]

I have a good, relatively coarse carborundum stone I use to re-shape edges, angles, etc that is the most dished.  It really does a nice job of re-establishing en edge or sharpening a really dull knife.  Then my next stone is a medium Arkansas stone that is still pretty flat but maybe not enough for sharpening gravers.  Then I go to the white Arkansas fine stone, then buffing compounds.

[D. Taylor Sapergia]

Rich, I use a new 80 grit belt on my 6" x 48" belt grinder to flatten stones.  It all but ruins a belt which costs about $9, so I don't do it too often.

[Kentucky Jeff]

Rub it on a cinder block with some water...it will flatten out in no time...

[E.vonAschwege]

I'm with Jeff on the cinder block idea.  For final flattening of water stones, I use a coarse daimond "stone". 

The really worn down stones can be broken up and re-ground into slip stones for chisels. 
-Eric

[omark]

i have done some flattening by rubbing 2 stones together. do it in some sort of figure 8 pattern or variation of. keep water flowing over the surfaces to keep them clean. still not easy or quick.      mark

[jerrywh]

Buy a diamong plate. Rub the stone on the diamond plate until it is perfectly flat. Then throw the stone away and keep the diamond plate for sharpening stuff. You might want a course and a fine one.

[Steve Bookout]

Sidewalks & cinder blocks is all I've ever used and the simplistic method works very nicely.  Cheers, Bookie 

[P.Bigham]

 I 2nd what Jerry said.    They last and dont need truing.

[rich pierce]

Am doing all the above.  Ordered diamon stones AND flattened one side of one stone on the sidewalk.  I used flint-knapping dust to help abrade it.  It helps, but it's hard work to take 3/32" off a stone.  Good for my arms and shoulders, I suppose.

[billd]

If you have two stones rubbing them together before they get real worn will keep them flat.
Bill

[J. Talbert]

I like Jerry's "words of wisdom"   

Jeff

[Curt Larsen]

Jerry's advice is good', but there is another way to go if you don 't want to get a diamond one.  I've flattened an Arkansas stone by using carbide grits used by lapidary guys in tumblers and spread it on a steel plate.  Then I made a slurry by adding water to it and just rubbed the stone face down and ground it until it was flat.  This also helps if you've clogged up the stone with filings.  It is pretty easy to renew the surface that way.