once burned.....

[Ken S]

I recently completed an on again off again project lasting several years.  I inherited a very cupped Indian stone from my grandfather.  Over the years, I have spend an hour with 90 grit carborundum powder; at least a couple hours with wet and dry paper; and finally about an hour with a Dia flat lapping plate.  It is finally flat.  I would not have bothered without the sentimental value.  Since I began using my Tormek, the oil stones get very little use.

The moral of this story is, regardless of whether you use oilstones, waterstones, or a Tormek, keep the stone surface regularly dressed and flat.

Ken

[Herman Trivilino]

Are there no power tools that could be used to flatten a stone like that?  My brother has some old sharpening stones that our Dad had, and they have a convex surface.  I have no desire to have them, primarily because I've never been able to sharpen a knife without a jig.  That lack of skill is what attracted me originally to the Tormek, and then led me to develop the HK-50.

[Ken S]

Herman, if I had to do it again, I would look into using sidewalk with water or a cinder block and water.  It is not a pleasant task, although regular refreshing supposedly keeps oilstones cutting better.

I don't know of any power tools for the job.

Ken

[Rhino]

Just chatting here.   I think the major problem is that while I can think of a number of ways to jig up a motorized something or other to flatten stones, it might not be cost effective.

I can figure out a number of ways to jig up the tormek to flatten a stone that is supposed to be flat.  A jig like the discontinued shaper jig would work - you would need two universal supports and some wood.  But, the Tormek stone is not cheap so I don't think that is a viable choice.  It would work because it is at least a wet system so you don't have to worry about heat.  Also, I don't know about the relative hardness, maybe the Tormek stone will be much reduced before the rectangular stone.

A dry system like sandpaper, grinder, etc would generate too much heat and use up too much sandpaper.

I have no solution except to note that a solution is difficult.

[Herman Trivilino]

I have a rather aggressive air-powered sander.  I don't use it much because it really uses a lot of air.  I suppose you could rig up a way to fasten the stone to the sander, and then sand it down on a wet cinder block or some other surface.

[Ken S]

From a logical standpoint, the most practical solution would have been to replace the stone or ignore it.  The fine India side was already flattened.  The coarser side (I'm not sure if it was India or carborundum) was the concave side.  It's work is now done on the Tormek, or in more extreme cases, the dry grinder or belt grinder.

Frankly, I put a lot of wear on a two hundred dollar diamond plate to salvage an old twenty dollar stone.  Not very smart.

A more practical fix would have been to rub the stone against a fairly flat concrete (cinder) block lubricated with water.

The lesson here is to be very fastidious about not letting a sharpening stone become dished.

Ken

[Herman Trivilino]

The lesson here is to be very fastidious about not letting a sharpening stone become dished.

Or perhaps to just toss it or delegate it to tasks that don't require finesse.  Like removing rust from the hinge pin of an old gate.   

[Rhino]

I have a rather aggressive air-powered sander.  I don't use it much because it really uses a lot of air.  I suppose you could rig up a way to fasten the stone to the sander, and then sand it down on a wet cinder block or some other surface.

You are right.  This is not my problem so I am actually not going to do it.  But if it were my problem, I can clamp the stone to my quarter sheet sander (using a clamp for sharpening stones) and then I can start electrically sanding my neighbor's sidewalk.  I don't have a sidewalk outside my house.

Thanks for the tip. 

[Rob]

I have a rather aggressive air-powered sander.  I don't use it much because it really uses a lot of air.

Is there a shortage of air near you then Herman :-)

[Herman Trivilino]

There's no shortage of hot air around here, Rob.   

[Rob]