Morning all, I originally raised this topic here on 30th may and received some helpful pointers as usual, thanks to all who contributed However, I've been away from the forum for a few days so i missed a couple of the final responses, so thanks again to everybody. One final thing, thanks to B Murphy, Royal Star for posting an image of a thread he'd recently cut. Correct me if I'm wrong but that doesn't look like a 26 T.P.I. thread. I'm having no difficulty cutting wider pitch threads or even 26 T.P.I. threads in small diameter bar. The problem is (as most folks have pointed out), anything over 5/16" diameter. Thanks again to everybody.