Thread cutting gear set up

[greaseape]

Good morning everyone; I am the owner of a South Bend heavy 10. The lathe is now in working order and I have been using it.
It came with a US to Metric transposing gear and a full set of gears to cut metric threads and I have done so a couple of times.
successfully.
What is not clear however, is what stud, idle and screw gears to use to cut US Standard threads. Can someone tell me how many
teeth each of these gears has, in order to cut standard threads, or where to find such information?
You can contact me directly if you want. Let me know what you need.
Thank you very much, Chipper.


P.S. I forgot to mention that the lathe is equipped with a 2 tumblers gear box.

 

[johnoder]

Might be helpful

http://campkahler.com/files/How_to_Run_a_Lathe_SB_1of2.pdf
http://campkahler.com/files/How_to_Run_a_Lathe_SB_2of2.pdf

 

[SLK001]

Which two tumbler QCGB do you have?

For the wide range QCGB, normal spur gear is 40T and normal gear box stud gear is 56T. Any idler that can span between the spur and stud gear will work - normally, it is an 80T. With this gear lineup, the brass label on the gear box is true.

EDIT: One more thing... CHECK YOUR SET-UP! Always run a light cut and check the TPI before you dig deep into your actual piece.