Harold,
No, it is not the same thing. A diamond wheel has small diamond particles permanently imbedded into a binder material. Most of the modern diamond wheels use some sort of resin that is chemically hardened. A lapping wheel is generally made from a “soft” metal such as cast iron or copper but wood is also sometimes used. The wheel itself is not involved in the cutting process but instead is “charged” with an abrasive paste. The paste could be any number of abrasive powders mixed with oil, grease or who knows, i’m afriad to ask. If you pull up some of the Steffan Pahlow videos on Youtube you can see him lapping watch parts. I think one is called “THE BLUEING OF SCREWS’ but there may be a few others.
david