Face thickness can be measured but the equipment costs a couple of thousand dollars. A friend of mine has it and I have been doing it for a few years. As far as being legal you have to maintain the .83 COR.
Charlie,
You are correct! I was addressing this issue from the standpoint of someone asking about this procedure using something as simple as a 6'" bench grinder in his garage! Doubtful that he is ready to spend a couple of thousand dollars on a machine to grind and then more money for a machine to measure the COR. I wasn't talking about a "scotch brite" wheel either. A finishing wheel costs $50-$70 and that seems to be out of the range of many hobbyists also. That's why I addressed the procedure of applying snake oil. This whole issue is in my mind bullcrap, unless you are prepared to spend the bucks and do lots of heads the right way!
Arnie
