Good evening,
What is the best way to measure threads on the CMM? I would just use a thread gage and put it in the report but I was asked to write them in the program. Thank you in advance.
When it comes to reporting true position of threads do you leave out the dia of the thread? If you do report the dia what is the tolerance? Do you just use the nominal dia pcdmis comes up with? There are a few different ways that people have programmed threads. Some left the dia out and just reported the position and some reported the dia with a tolerance. I just cant seem to figure out how they came up with a dia and tolerance.
I only report the position when measuring threads. To many form variables like burrs and debris that will report inaccurately in regard to the major/minor diameters. Thread gauge, Pins etc. are the only way to report size in my opinion.
Always ensure your pitch is set properly as well
Form errors also affect position......
Using the pitch function in auto circles/ auto cylinders generally works well. Threads have to be well formed.
Difficult if not impossible to get a highly accurate minor thread diameter using a CMM. Major and Pitch Diameters are impossible.
I have used threaded inserts to improve position results but they are a royal pain to remove and replace. They get lost easily and you will forget to put one in on the hour-long program for the hot part that you're running.
