Water stone question

[Robert Engel]

Do only certain stones require a Nagura stone?

I have a Norton 8K and Shapton 16K.

I have one, but never use it, seem to get fine results.

[ken hatch]

Do only certain stones require a Nagura stone?

I have a Norton 8K and Shapton 16K.

I have one, but never use it, seem to get fine results.

Robert,

Synthetic stones and JNATs abrade differently. Synthetic stones have crystal shaped grit that abrades and is turned loose from the stone's matrix as you sharpen. The grit in the slurry doesn't break down that much so it has little effect on sharpening it is mostly a stone surface to steel process. I've only had one synthetic stone come with a nagura and I could not see or feel any difference when I used it on the stone. A JNAT is different, the abrasive particles are flake like and do break down in the sharpening process, for a JNAT to work properly you need the slurry and the best way to get slurry is with a nagura. The harder the JNAT stone the more you need a nagura. It doesn't hurt to use a nagura on a synthetic stone but I doubt you are gaining anything.

ken

[Bob Jones 5443]

Ken, interesting discussion. I have always accepted (blindly, probably) that I should use a Nagura with my Norton 8000 stone –– a synthetic stone. You're saying it might make little difference. To tell the truth, I've long suspected that. Where's the evidence?

[ken hatch]

Ken, interesting discussion. I have always accepted (blindly, probably) that I should use a Nagura with my Norton 8000 stone –– a synthetic stone. You're saying it might make little difference. To tell the truth, I've long suspected that. Where's the evidence?


Bob,

About the only thing a nagura is good for on man made stones is it can help keep it flat so you do not have to go to the plates as often

ken

[William Fretwell]

On my 10,000 grit synthetic used without a nagura you get black streak marks on the stone. For a large blade like a plane blade those black marks won’t cut as well as the rest of the stone, if at all.
With a nagura slurry the black streaks don’t form to any real degree so the cutting surface will be more consistent, if perhaps a little slower. It’s not that you just don’t see them as when you rinse the stone they are not there.
If the cutting is a little slower it matters not as this final stone ( for me) is usually less than 10 gentle strokes and a back polish.
So I suggest it improves the consistency of the stone surface.

[ken hatch]

On my 10,000 grit synthetic used without a nagura you get black streak marks on the stone. For a large blade like a plane blade those black marks won’t cut as well as the rest of the stone, if at all.
With a nagura slurry the black streaks don’t form to any real degree so the cutting surface will be more consistent, if perhaps a little slower. It’s not that you just don’t see them as when you rinse the stone they are not there.
If the cutting is a little slower it matters not as this final stone ( for me) is usually less than 10 gentle strokes and a back polish.
So I suggest it improves the consistency of the stone surface.

William,

I'm not a fan of nor a heavy user of synthetic water stones. I have 'em, just find other stones work better. Of course YMMV. If I'm getting black streaks on the stone it is usually because I've let the stone dry. You are correct, if black streaks develop a nagura is a good tool to remove the streaks.

ken