[How do I?] Do 20 TPI

I'm thinking that if you set up a 30 tooth gear on the QC box and set the box up for 40 threads, you will get 30TPI; I have some notes on this, but try it and if it does not work I can dig through my notes and find it. I have done this on my lathe for such as 19TPI, using a 38 tooth change gear and setting the levers accordingly; when I was in business, I made a whole set of change gears to be able to do not only metric, but also diametral pitch and other special leads; it's a big pile of gears. I had found some charts related to the heavy duty Leblonds and it worked for the Regal as well.
 
Okay so false alarm on my end. Checked things out tonight and I guess I've only ever turned metric threads because I never thought to change the side gearing for the imperial thread I tried to cut.
:oops2:

My threading chart looks normal and I'll run a test at some point to see if I can successfully machine imperial threads. Just a weird coincidence I had attempted a 20 TPI very recently and could only engage the mating thread partially.

Bamban, glad to hear you've gotten to the bottom of your issue! And it definitely helped solve mine! So, thanks everyone :encourage:

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