[JDenyer232]

I have a project coming up that is going to require me to turn 1/4-28 invar screws from bar stock. Any ideas on feed and speed, I was thinking 130SFM at .002-.003" per rev. Any tips on threading, I will be using full profile laydown inserts, I was planning to use G76 with 5 passes. Any tips and tricks would be greatly appreciated. Thanks in advance to all that reply.

[JDenyer232]

Just a quick bump and a progress report on this issue. I used the recommended speeds and feeds out of the book for this material and turning it was fine. I did run into a major issue with chattering while threading. The threads looked terrible. I played around with the threading portion, ie G76 and discovered that using an A55 modified infeed produced excellent results. We even turned some 4-40 screws out of invar and they looked great. Just thought I'd give an update in case anyone else runs into this issue.