Thread: Lapping a lapping stone???

I think in theory if you rub two stones togeather that have irregularities, the rubbing should remove the irregularities from each other. Making two flat surfaces. At least in theory.

In theory yes, but if you rub a chinese 12k, which is quite hard, against a Norton lapping stone, which is low grit and quite soft, the lapping stone is going to lose a lot more material before the 12k is flat. Also, a problem arises if the lapping stone is not the same size a the hone, causing surface contact differences.

Buckler, in answer to your specific question, I would say that the Norton lapping stone comes flat and does not need to be lapped. In my experience with the 7 Norton hones I have bought, they definitely DO need to be lapped prior to use. Also, the concerns/complaints about the Norton lapping stone are much less relevant if you only use it on Norton hones. The Norton hones are softer and they are the same size as the lapping hone so the wear on the lapping hone will be much more uniform.

Thanks for the input guys, i am greatful.
I have bought a 220/1k 4k/8k of Don and its lapped so i wont need to
But i dont think ill go out of my way to buy a Noton lapping stone now. I was initially thinking of getting a set of Nortons, but now that i have these two for a great price, ill just do the sand paper on the bench idea.

Its been good info though. Thankyou every one my knowledge has been expanded, and i think i will one day get a DMT due to the advice here.
Thanks guys

+Buckler

Nortons do have to be lapped first as they do not come from the factory flat. I use a DMT 8" coarse continuous diamond to do the lapping. I carry the Norton lapping stones and they should be fine for lapping Nortons without having to be lapped themselves. Rubbing two stones together like that tends to flatten both and usually to a spec flatter. The important thing to remember when lapping is to use the whole stone and not just the center. That's what leads to "dishing" and other problems.