Anyone here try tapping 3.5M x .6 threads .16 deep bottoming in soft copper plate 1/4 thick? This is what the Boss wants so helicoils are out of the question.
First problem: When Drilling with a #30 stub drill the holes blow open to .137 diameter. I've tried slowing the speeds and feeds but the drill still packs with chips. Also tried using a 1/8 drill, and still no dice. The machine is a Cat40 HAAS VF-3 in very new condition.
Next problem: Roll Tap (Form) or Cut Tap? Which would be best?
All work has to be done on the CNC Mill in large quantities, and all ready scrapped 5 parts.
First time machining Soft Copper. Lost and Confused, and the Boss isn't happy either.
Thanks for the Information in Advance.