- Nov 28, 2017
I would check,I'm thread milling various ID threads (1/2x28 to 13/16x16) and the all have the same problem. When I'm testing the thread fit, the test parts will screw in 2-4 full rotations and then the threads get tight until you can't thread the test part on any further. This is with all threads I'm machining. I've checked the run out on my tools, I'm doing multiple spring passes, and I've check and verified the minor diameter, thread pitch in the program is fine, everything checks out okay. I'm running out of ideas, hoping some of you might shed some light on it. I've got only one thread mill I'm doing these jobs with, so I don't know for sure if it's the thread mill or not. I've also checked my programing to see if it's threading some sort of tapper, everything looks normal (using Fusion 360.)
Let me know if there is anything else I can try. Thanks!
are you milling the holes? if so, is the tool deflecting? measure the holes at the bottom before thread milling.
It is the only parameter I can see that would change from the top to the bottom,
especially when your using a single point for threading afterwards.
other than the machine not cutting the pitch correctly.