Quote Originally Posted by CLaReNCe View Post
Ok.... I understand that lapping makes the stone flatter- this part I get.

But..

How can you lap a 10,000 grit stone with a 250/400 grit sandpaper, and not have a bunch of scratches in it?

Oh... And should Nagura stones be lapped at the same time as hones? or does it not matter so much?

Peace Comrades...
It is not an issue for the function of most stones but if it concerns you you can use another flat stone to further polish.
Nagura & all stones should have lightly chamfered, smooth edges but the need for uber flatness of Nagura is debatable, after all it is usually softer than the base stone.
I remember seeing a recommendation to use the edge & not the flat for a particular slurry stone so in that case it would also be unnecessary to flatten.
If you mean a small 'truing' stone as supplied by some synthetic makers, it should be flat, as in that case it could be harder than the base stone.