Thread: Burnishing and Jnats

Originally Posted by Marshal

In general this has been my experience as well. Whether we're talking about an Arkansas stone, my PHIG, my Jnat, or one of the Welsh slates they do seem to perform better (slower perhaps, but polish better) when they've simply been used for a few months and not lapped constantly for fear of it getting out of flat. Needless to say, at this point with harder stones I lap less, and just let the hone be what it is. If they get out of flat then I'll worry about it. My diamond plates probably appreciate this too, the PHIG really wears those poor puppies out.

Makes sense. Finishers shouldn't lose flatness for the few light strokes they get used for.

[I]“They glaze to some extent, like an Ark maybe. I can de-glaze the stone (and nagura) and it works faster, but does a hard, glazed, jnat act finer like a hard burnished/glazed Ark? I think maybe a glazed hard jnat does finish finer than an unglazed one.”[/I]

In theory yes, but, as said they are different stones with different shaped grits, hardness and binders. Jnats are not as hard as Arks, so while the stone can burnish, (the tops of the grit are flattened) grit comes loose and hard loose grit scratches the bevel and can result in edge chips.

I believe a lot has to do with the shape of the grit, and of course the binder. Jnat grit is flatter and therefor not as deeply suspended in the binder.

For this reason, I do not finish on water and use a lite slurry, that acts as a lubricant, preventing scratching and chipping on hard Jnats.

Glazing is different from burnishing, we see glazing, swarf build up on some synthetics, Naniwa Super Stones are notorious examples. That glazing swarf build up keeps the edge off the grit and can edge impact leading to edge chipping. The swarf is steel, grit and binder mixed and bonded to the stone surface. A quick lite lapping removes the glazing and refreshes the stone face allowing it to cut and polish.

Is some of that also occurring on a hard Jnat? Possibly.