Thread: flattening honing stones.

Originally Posted by aaron1234

My reason is because I have a stone that is over 11in. they don't make sheets of high grit sandpaper large enough to lap this particular Stone properly.

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We do have them in the Netherlands. I have flattened long Lynn Idwals and Charnley Forest hones with sandpaper. And they are buggers to lap.

Yup many ways to do it, for soft stones like slates and coticules, drywall screen is quick and easy.

For hard stones, 60 grit will get you flat in a few minutes. There are many threads, on flattening stones mostly in the Ark stone post.

For Arks and other hard naturals, it is not uncommon to go to 2k or higher on Wet & Dry then burnish with hard carbon steel, for an even finer smoother stone face. If you need longer, just glue 2 sheets to a cookie sheet. Works just fine.

Nice post, thanks for posting.

Aaron, get it flat first with 60 grit, Zulus are hard, then work up the progression to 500. From there your slurry stone should take it the rest of the way.

Most Zulu’s I have seen were pretty flat. Dead flat is a myth, smooth and flattish is good enough. And if you use glass as a substrate, after the first lap, the glass is no longer flat.

Glass is not flat to begin with, I use glass for film, and I have to flatten it first.

Originally Posted by Euclid440

Aaron, get it flat first with 60 grit, Zulus are hard, then work up the progression to 500. From there your slurry stone should take it the rest of the way.

Most Zulu’s I have seen were pretty flat. Dead flat is a myth, smooth and flattish is good enough. And if you use glass as a substrate, after the first lap, the glass is no longer flat.

Glass is not flat to begin with, I use glass for film, and I have to flatten it first.

Euclid; I am a little confused with your wording. You mention this;

Most Zulu’s I have seen were pretty flat. Dead flat is a myth, smooth and flattish is good enough.

then state this;

Glass is not flat to begin with, I use glass for film, and I have to flatten it first.

StewieS.

There are folks who obsess about flatness of stones and want to keep their stones absolutely dead flat and claim that you can only get a straight edge from a dead flat surface.

But you don’t need absolute, dead flat, yes when first purchasing a stone it is good to flatten them, but there is no need to obsess about flatness. Most of the pro honers I know, do not re-flatten with a grid pattern after the initial flatting.

They just keep it flattish, with a quick swarf removal with a diamond plate. Their stones are probably pretty flat, but not perfectly flat. The work does not ride in exactly the same spot and most honing stones, both synthetic and naturals are friable so the surface is self refreshing.

Glass is not flat, when use with Silicone Carbide, it quickly will go out of flat and dish. There are better options, steel for one.

I use glass plates to hone on film and have found them way out of flat, so a quick lapping with 220 wet & dry or a 300 diamond plate will quickly bring them flatter and a more efficient substrate for film honing.

The only benefit of a flat plate is efficiency, because more abrasive is in contact with the work surface. The work will ride on the high spots and for sharpening the work will still be flat, as long as, the stone face is smooth.

You can get a flat edge on a concave stone, not what I am recommending, but can be done.