Of course there is a science to threads, lots of standards, definitions and tolerances. I have plenty of books on the subject. The issue is the PP conversational for millings them. The tooling bits sold by Tormach look to have the same sharp point as the ones I have from SCT. Trying to modify a carbide thread mill with a known root form is not that easy if you’re trying to meet specifications.
So the question is using the standard sharp point tool what are the parameters to use in the conversational to get a decent fit. I view this conversational as just a quick & easy way to get a thread made with an off-the-shelf tool. If I had to meet a certain “class” I don’t know that I would use this methodology.
I didn’t spend a lot of time trying the scientific approach because I just wanted to get it done (the point of this conversational) but I did make some notes and could not reconcile them with how the conversational should work thus my statement.
If someone has a method to use with the conversational to utilize a sharp point tool that does not require some trial & check fit I would like to know what it is? Tormach only states:
NOTE: The values entered in these tables assume a full form thread tool. If using a fine point threading tool to cut coarse threads, the root diameter must be modified to account for the smaller tool nose radius of the fine point threading tool.
"dannirr" has his app but doesn’t really state if it’s output is applicable to the conversational, what the calculations are, or if it deals with fine, coarse, metric threads correctly.
"rcaffin" notes their will still be some experimentation…
Yeah I know there are calc’s that "dannirr" uses but the one’s I found on the internet & my handbooks only got me closer using the Tormach conversational. Still had some trial & error.
So in the mean time as I learn what parameters work for me I just add them into the custom thread file that Tormach provides in:
operator/gcode/thread_data/custom_threads_xxx.txt
Note: Replace “xxx” with either “metric” or “sae”.
Then it’s just one click to make a thread that I know works.
As "dannirr" points out it would be nice if Tormach included this calc in the conversational but my feeling is that it just doesn't work hence the custom files.