Posted by a guy on March 14, 2001 at 20:30:36:
In Reply to: valve specs wanted posted by Dan on March 14, 2001 at 20:07:21:
rotors are usually rough-CAST first, and then machined. Does your friend have a way to cast bronze?
(The casting is how they get the "cut-outs" without going to unbelievable trouble. btw, not ALL rotors are cast, but many are.)