On May 7, 9:29*am, "Bob La Londe" wrote:
So what's the proscribed method? *I expect I need a pretty consistent radius
bottom. *What's the best way. *Make a rough semi V lathe bit, and then make
a decent round one to finish?

The Parker O-Ring Handbook (9 Mb) discusses some of the design
criteria for o-ring grooves. See Section 4:
http://www.parker.com/literature/ORD...g_Handbook.pdf