Converting Taig Mill to Variable Speed

Cost in Fall 2009 is approx $110

I read, on the Taig users group, a note from Bob Swartzendruber, inquiring about use of a DC variable speed motor and controller that was available from Penn Industries for $85 (as of Oct 2007). I decided to try it out as a variable speed conversion for my Taig mill. The motor is intended as a conversion kit for a TCLPRO, Jet or Delta wood lathe. It required minimal modification to fit on the Taig mill and seems to work well (although I have no long term performance). It can be ordered at:

This is the kit you receive when you order:


The box specifies: 110V, ½ hp

Variable Speed 650-3800

I have no way of measuring, but I am fairly certain that the speed range is for the lathe spindle including the step-up/step-down effects since the motor comes with a 3-step pulley and envisions a lathe with the same. I believe the motor speed is actually about 1250-2800 rpm.

The conversion was relatively straightforward. The motor shaft is larger than the stock Taig motor so a pulley either has to be made or a Taig pulley bored out (this was what I did). Also, to provide proper alignment of the motor pulley and the headstock pulley, you either have to 1) shorten the motor pulley, 2) step bore the pulley to allow it to go up the motor shaft further, or 3) raise the motor on the mounting bracket so that the shaft doesn't stick down so far. I chose option 2 plus about 3/8 in of shortening to make it all fit right.

The motor rotation direction needs reversing. The easiest way to do that is remove the cover from the controller and reverse the two spade connectors going to the output cord from the controller. 

The stock mounting bracket works fine as the weight of the DC motor and the stock Taig motor are about the same and the size is similar.

I made an L-bracket about 2 inches wide with a 3 inch and a 6 inch leg to mount the controller. I used the same threaded screw holes that Taig uses to mount the original switch.

Here are some pictures of the finished product.