- Joined
- Sep 11, 2015
- Messages
- 293
I'm having a heck of a time tapping 304 SS. They are blind holes being tapped to m12x1.25 in 2" OD 304SS, 1.25" deep. I drilled to 27/64 for 75% thread, then failed. I then drilled up to 7/16 for 50% thread and failed again. I can get my tap started, but that's about it. It feels like the tap just wants to snap.
I know SS work hardens fairly fast. I step drilled up to the given sizes and made sure to use plenty of cutting oil and not let the bits dwell. The work never got too warm and neither did the bits.
What should I do differently? I know my taps aren't the best quality, but they cut threads in 303 SS with some effort. Am I just experiencing the less machinability of 304? Now might be a good time to warm up my internal single point threading skill (or lack of).
I know SS work hardens fairly fast. I step drilled up to the given sizes and made sure to use plenty of cutting oil and not let the bits dwell. The work never got too warm and neither did the bits.
What should I do differently? I know my taps aren't the best quality, but they cut threads in 303 SS with some effort. Am I just experiencing the less machinability of 304? Now might be a good time to warm up my internal single point threading skill (or lack of).