Thanks for all that info!
Hmmm, here is something that might help you if you are going to do a lot of threads like that:
Manual programming! OMG!!!! No, seriously....
You could save a ton of time by doing the roughing with some simple lines of g code.
Here is an example:
Assume the left end by the indexer is X0 and the diameter of the thread is 2 inches and you want 8 threads per inch over a distance of 10 inches. (this is wrapping Y)
G0Z1.5 (make sure tool is above workpiece)
G0X10.25A0 (move to X value and rotate indexer to 0)
G1Z.875F35 (feed to take a cut .125 deep)
G1X0A2880F150 (do the rough cut)
G0X10.25A0 (position for next roughing cut)
All of this is pretty straight forward until you get to the line with the A2880 in it.
The 2880 is obtained by knowing that you are cutting 8 threads per inch and you are doing it for 10 inches. So you have 80 turns. There are 360 degrees in one turn, so 80 X 360 = 2880.
I have made quite a few screws for guys in the woodworking clamp to build wooden vises. I learned very quickly to stick with 60 degree threads for a bunch of reasons. Most importantly is that finding a cutter to use in making the nut is tricky enough without using some obscure shape. I have 2 inch, 8 TPI on my workbench that have been used for about 20 years now with no chipout. Had an antique bench that was all beat to hades and the only really good parts were the nuts and screws.
"If you see a good fight, get in it." Dr. Vernon Jones