Thread: Lapping a Norton 4k/8k

Mark,
Flat is a relative term and not an absolute. In industry you have to specify the flatness. When sharpening razors though, the flatness on any stone that can be achieved by lapping on a DMT Coarse continuous diamond hone is "flat enough". At $55 they're almost double the cost of a Norton flattening stone BUT and this is big, you get a lifetime tool that will sharpen ANYTHING in addition to lapping waterstones. They never dish and they last forever. I've been lapping coticules for 5 years on the same stone and I always test with a machinist's straight edge before and after lapping.

Norton stones are usually flat enough to hone razors right off the bat BUT the surface is greatly improved by lapping. Why? These are vitrified, or baked, stones. The immediate surface is different from what is just under it. You can let the stone "break in" gradually over time or you can lap it.

I have talked with folks who have used sandpaper on glass, lapping grit on surface plates, etc. but eventually they come to the realization that, for consistent results, you want a high quality tool. That's why I use and carry DMT stones.

Thanks for the great pointers guys! I had no idea lapping a stone was this involved or had so many variations in technique or tools!

I think this is why this forum is so important to all of us, new and old - it is the perfect venue to gain information and exchange ideas.

Thanks again, and now I have to go rethinking my choice in lapping apparatus!

Mark