Taig Lathe V3

I documented my first attempt at swapping the single phase induction motor on my Taig lathe for a DC motor and Arduino control system last year. There was some interest and I have now reached the stage where V3 is working as designed if anyone is still interested!

The original solution had a few issues (OK design faults!) the worst being that the back end of the motor stuck out beyond the headstock. It was not an issue with chucks, but working with collets close up to the headstock it became a bit of a nuisance. It also lacked low speed torque and the cabling was a mess, so I decided on V3 and to invest in a BLDC motor.

Several people had cantilevered the Sherline motor and controller from the Taig headstock and as the motor I chose weighed about the same, that seemed a good approach.

I had three other "ambitions" for the lathe. A decent mounting base, screwcutting capability and some form of power feed.

The base was inspired by Roger Hess' (Technitoys) superb version with the control panel at the front, wiring hidden in routed channels and a cover at the rear over the electronics. Mine is is constructed from two layers of 22mm MDF glued together. The top layer had cut outs for the electronics at the back and channels routed in the bottom for the wiring. The front is chamfered and cut out for the controls. I then covered it with a sheet of 0.5mm 308 stainless steel (Don't look too closely at my first attempt at sheet metal work!).

The control panel, covers for the electronics and mounting for the display were all 3D printed. The cover is in two parts to fit the 3D printer bed size. The panel lettering was subtracted from the panel and filled with acrylic paint. A wet Sunday afternoon with the CAD program also produced a(n over the top) design for a belt guard.

John Bentley's (Engineman) site and Rodger Hess suggested ideas for both a Unimat style thread cutting capability and a leadscrew for power feed together with an end plate for the lathe bed to support things. A You Tube video from Walter Maisey used linear bearings for the threading attachment's push rod. I thought that if I used a pushrod to drive the carriage, then coupling it to a DC motor driven leadscrew would enable me to have both functions - selected by locking the appropriate drive bars to the pushrod. The ideas evolved into this.

A geared 60rpm 12v DC motor in the lathe foot couples to the leadscrew by a dog clutch with a handwheeel for manual use on the other end. The pushrod is carried on two linear bearings mounted on the lathe foot. The carriage drive block and both coupling bars are locked onto the pushrod as needed with split cotters. The sample thread is held in an ER16 collet on the end of an arbour inserted into the spindle.

Control is by an Arduino which provides pulse width drive to both the BLDC spindle motor and the leadscrew motor. The control panel allows selection of the motor power and direction for both motors as well as run-stop and full speed override on the leadscrew for easy positioning. The display shows spindle, BLDC motor and leadscrew RPM as well as a computed feed rate (microns per rev of the spindle).

Power feed works extremely well. The screw cutting has only been tested experimentally so far, and still needs the backgear system I made to get sufficient torque at low spindle rpm to be useful. But overall I am pleased with the outcome. There are pictures of some of the details in my album called Taig V3. As ever, comments, questions and suggestions gratefully received.

An electric sewing machine motor with the pedal speed control modified has been used successfully on small lathes. Not as sophisticated as your solution.

Edited By old mart on 10/04/2022 18:28:01