07-31-2012, 08:11 AM
(This post was last modified: 07-31-2012, 08:30 AM by Sunset Machine.)
I don't know, Tony. Consider the helix angle. Flat on top results in a positive rake that matches the helix angle, with a likewise negative rake on the trailing edge. Easily seen from the side, especially with larger pitch threads. Same reason why we need extra clearance on the leading edge.