Will it matter if the stones in my Lansky are dished?

S

Squashfan

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Jun 6, 2012
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I just picked up a used non diamond Lasky for $20. The stones are slightly dished. The dish is from end to end. It starts gradually at the rod end of the stone with the deepest dish in the middle. Which gradually lessens toward the other end of the stone. I am wondering if that could round the apex.

FYI, when I sharpen on the Lansky I do one stroke up and one stroke down in a sawing motion. I am testing this technique after seeing people sharpen this way on benchstones.
 
Seems like it could slightly convex the edge bevel. I'm sure the finished edge will perform just fine.

I also use the up-down motion on my Lansky when I am reprofiling or forming a burr. Technique matters more and more as you get near the final steps of sharpening, but on the earliest steps I tend to use the easiest, fastest technique.
 
In my opinion, it will matter very slightly. Since the stones wear out when the middle portion is expended, there is no real loss in flattening them as long as you stop when you get to the middle worn section.

Now, to level them, I'd suggest a cheap silicon carbide bench stone since I have one, but figure an old rusty file or even some flat concrete would probably work. I'd also take a sharpie or something and mark the center section so I could tell when I needed to stop.

I always sharpened on the downstroke.

And to finish it all off, explore stropping, and for the cheap, look at green polishing compound (big box home improvement store) on balsa wood (big box hobby store)
 
Nullity said:
Seems like it could slightly convex the edge bevel. I'm sure the finished edge will perform just fine.

I also use the up-down motion on my Lansky when I am reprofiling or forming a burr. Technique matters more and more as you get near the final steps of sharpening, but on the earliest steps I tend to use the easiest, fastest technique.
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Are you saying that I should not use the upstroke and down stroke technique when I am in the finishing stages of sharpening?

Also, how do I tell when stones are worn out?
 
Dished stones are a pain on guided systems, because as you progress to the finer, slower wearing stones the edge won't contact, and you waste alot of time trying to basically grind down more steel with a flatter fine stone that should have only taken a few strokes to refine. You can either flatten the stones using some grit and a flattening plate (or a convenient paving block) or raise the angle so you're only needing to put on a microbevel with the finer stones.
 
I just really looked the stones over and to my surprise the fine stone is covex not dished.

Yoda, I think I have heard you mention the paver and grit method before. Would some sand and a smooth concrete paver work?
 
Yep, it sure would. Grit, a flat surface, and water and you have a lapping surface for a stone. (I should add that this works best on the coarse stones that wear quickly, the fine one will be flattened using this process but sand might be too soft to do it quickly)
 
Squashfan said:
Are you saying that I should not use the upstroke and down stroke technique when I am in the finishing stages of sharpening?

Also, how do I tell when stones are worn out?
Click to expand...

Edge trailing (down) strokes are gentler on the apex but you also form a burr easier so many use this stroke for final stages of sharpening.
I'm sure there's some threads on the differences between edge trailing and edge leading strokes.
 
Nullity said:
Edge trailing (down) strokes are gentler on the apex but you also form a burr easier so many use this stroke for final stages of sharpening.
I'm sure there's some threads on the differences between edge trailing and edge leading strokes.
Click to expand...

Fascinating.

As to the lapping, as long as sand doesn't take, say, 2 hours to lap a stone, I should be fine. If I were to replace the sand with something else for the fine stone, what would you recommend?
 
I have aluminum oxide 150 grit sandblasting abrasive sitting around that works fine. Also, a flat DMT coarse plate also works great for any stone finer in grit than the plate is.
 
My local Lowe's doesn't seem to have sandblasting abrasive. I will try to lap the fine stone with sand and see what happens.
 
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