Couplings

What is the best way to connect a lead screw to a bag motor.

The lead screw is 1/4-20.

Thanks for the help.

It should be pretty simple. You’ll need an end of the lead screw turned down to a round shaft, and an appropriate shaft coupling to link the output shaft from your gearbox to the round shaft of the screw. Here is the page for shaft couplings on McMaster-Carr. Also, make sure the screw is properly supported along its length, because they don’t turn so well when they’re bent.

I’d also like to know what sort of reduction you’ve decided on for your motor, since a 20 TPI lead is really small. Just using the BAG motor’s free speed of 14,000 RPM, that gives you 11-2/3" travel per second (way too fast for almost anything). Since I’m assuming this is a high torque application, you will probably be using something like the VersaPlanetary 100:1 gearbox, which puts you down to little more than a tenth of an inch per second (ideally, in reality it could be even worse). Hopefully some ratio in the middle of those gives you enough torque to do what you need without taking forever, but make sure you’re always doing the math on these things.

We’ve made a simple coupling now and plan to test it Tomorrow.

This is not a high torque application so we are doing direct drive at 50% speed.