13 tpi

[mksj]

The ELS4 is just the controller, so you can put whatever driver/drive you choose (DC stepper, DC servo or AC servo). A Nema 24 motor with 2.2 Nm torque on a 4 mm spindle generates a thrust of about 1400N, which corresponds to a weight of 140 kg pulling on the bed slide. The ELS4 is more of a full featured ELS in that it drives both the X and Z axis, and has a higher level of automated control, so like with threading it can do a number of different cutting profiles such as radial, flank infeed, modified flank infeed, and alternate flank infeed. So semi-CNC functions.

 

[Winegrower]

For some reason, my lathe also does not handle 13 TPI without a gear change. I wouldn't care, except that the hold down rods and nuts for the Bridgeport are all 1/2-13 threads. Occasionally I wish I had a particular length rod, but it's not worth changing gears, so far.

 

[mikey]

Cutting worm gears, either in inch or metric sizes.

Sent from my Pixel XL using Tapatalk

This. Diametral for Inch and Modular for Metric worm gears.

 

[RJSakowski]

Would any of their complete kits be stout enough to drive a 1236 lathe?

As far as I know, they don't include the stepper/servo motors and drivers nor the encoder. This from their ELS4 user manual.

You would have to pick those items to meet your requirements.

 

[macardoso]

I rarely walk up to my lathe and just quickly pop something out. Lately I'm often doing complicated setups with indicators that might take an hour or two to get going. In this context, changing gears to cut a particular thread isn't a big deal to me and just seems like part of the normal process for setting up a part.

If you need quick and convenient, an ELS seems reasonable but you can also look for a geometric die head which would make short work on repeated threads.