Has anyone had a go at machining a two or more start internal thread using the thread milling cycle to produce a threaded nut in the region of 1 1/2'' diameter if so how succesful was it and how did you command the tool to start in the other helix lead-in positions. cheers Colin
You can either start the second cut at the same Z position as the first but on the opposite side of the circle or on the same side as the first but with the starting Z half a pitch (or is it half a lead?) above or below the first.
I haven't tried this, but I expect if you didn't want to change the starting Z (the usual method), you could apply a Subprogram/Rotate to the Thread Milling cycle. The start angle for the Rotate would be 180 degrees (or 120 degrees for three starts, etc.).