I use diamond compound. I normally use barrel laps like those shown by Aeromotor8 in his post. There are a few precautions that you should take, but these apply to most other compounds also.
1. Charge the lap by rolling it over a hardened steel surface that will force the diamond into the lap. Then remove the excess compound and use oil on the lap during lapping.
2. The lap must be considerably softer than the part being lapped.
3. If you use a roughing and finishing compound, use a separate lap for each. You can buy extra barrels for the laps above. Mark the barrel with the grade of compound you have charged it with.
4. Clean the part completely and throughly before test fitting with a mating part. I do a solvent rinse followed by detergent and hot water with a test tube brush or bottle brush. One well known model builder, whose name I can't remember, advocates using an ultrasonic cleaner as a final step, but that is probably overkill.
My personal opinion is that I don't think that diamond is any worse than other hard abrasives about imbeding in the work surface. Silicon carbide is so hard compared to metal that whatever problem you might have with diamond you will have with it.
There is a family of compounds that are marketed under the name Timesaver. They are made by Microsurface Corporation.
Web site is
www.ws2coating.com
These compounds break down rapidly and are marketed as "Timesaver compound will not imbed into any metal surface and will not continue to cut."
Gail in NM,USA
