I am new to thread milling. I need to cut internal and external 7/16-20 threads in Delrin. I have a Tormach 34694 thread mill. What should I use for DoC and feed and how do I calculate it? I have GWizard but I'm confused how to enter the parameters. I assume that "tool diameter" should be the shank diameter (3/16) rather than the cutting diameter (0.180). Does 3.2ipm at 3500 rpm (so that I don't have to move the belt) seem reasonable? I hate to break things!