After I had read this short paragraph about left-turning , my decision was clear and concise: I wanted to awake left-turning for a second time, because I felt, although it was mainly forgotten by professionals, it is worth to be kept and fostered as a great hobby.

As my aim was left-turning and not lathe engineering I wanted to make the lathe as simple as possible. So I covered a collector motor form an old table centrifuge with an aluminium chassis and applied an electronic speed controller to this drive. (The motor is powered with only one alternation of the ac power supply. The reason for the feedback control is to reduce force and speed of the drive and not mainly to get a variable speed.)

This unit serves as head stock and as drive of the lathe as well. Usually the shaft of the head stock (which is in my case the shaft of the motor) has a thread, to hold the chucks. As I had simple solutions in mind, I disliked the Idea of cutting left hand treads on the shaft and into all the chucks I had to build in the future. Finally I found an another solution: I attached the chucks directly to the cylindrical shaft end of 10 mm diameter, using a M4 slug screw for each chuck. But ongoing tests showed that this idea was not perfect. The screw damaged the surface of the shaft and the slot of the locking screw was also damaged after a short time of working. Now I use slug screws from allen screw type, which withstands more force. And I turned a grove inside the hole of the chucks where I inserted a steel ring made of a short piece of a clockwork spring. So the steel tape protects the shaft against the screw.

How to reduce speed?

As you can see from the identification plate (Fig. 3), the nominal speed of my motor is 8000 rpm. That's a bit too high for a lathe, even if only narrow parts have to be turned. I coped with tis problem by soldering a simle speed controller together. It's circuit diagram is shown on Fig. 6. I found it on reference book for radio amateurs, originally designd for refitting a spped controller to portable power drills.

Circuit diagramm of the speed controller

Fig 6: Circuit diagramm of the speed controller, found on a reference book for radio amateurs, originally designd for refitting a spped controller to portable power drills

Liability exclusion: Assembling electronics components can be really dangerous, if undertaken by layman! I have also no idea if the design is patent pending or under someone's copyright!