Lapping compound is not polishing compound...two different things. Lapping compound is effectively a fluid file that will remove a surprising amount of material (steel) in a very short order. I've personally hand "lapped" I don't know how many valves to seat them in cylinder heads (before hardened seat inserts) using this compound. Trust me it's quick.
We know it is relatively quick but not near as quick as you seem to imply. The method has been used for years. Why not do some investigating in the process before you pass judgement. You clearly are working on some preconceived idea as if the process is just a new revelation. It isn't, it works and has an added benefit that you will discover if you do your research.
Try the Cast Bullet Forum for starters and remember Google is your friend.
Take Care
Bob




















































