not sure if this is the right section, if not mods feel free to move me.
i am having trouble with some thread milling. i cut the threads (external( the program runs fine, the machine cuts fine, the threads are beautiful. the only problem is that the off the shelf nut does not fit. lets just say for example i am cutting 1 3/8 unf 2a.
i am using a treadmill just like this one
http://cdn.mscdirect.com/global/imag...4023293-23.jpg
the tool is set up correctly and appropriate for the threads i am trying to cut.
i am pretty sure i am just missing something when i program the cut. i am using mastercam. and running on a haas vf3
i set the tool path to cut a dia. of 1.2739 and i cut the od of the thread to 1.370. is there something i am missing? i can get the threads to fit perfectly, but i ususaly have to end up taking around another .030 off of the cut dia. 1.2739 down to something like 1.2439. at which point the off the shelf nut fits beautifully, but i should not have to do this. it seems like i am missing something. hopefully someone can point it out to me. my guess is that is has something to do with the fact that the thread form is supposed to be square on the inside, and the cutter i am using is pointed. so perhaps i have to cut deeper by the distance of the square thread form to the point of my cutter?
thanks in advance for any help