Electronic speed reduction on conventional headstock?

[nogbert]

I'm wondering if anyone had ever tinkered with using an in-line potentiometer or other variable control element to reduce the base output velocity of the electric motor. Seems like someone surely could come up with something along these lines that would allow for very slow spindle speeds for large turning or giant drill bits etc.

[DLB]

Yes, people have tried that. I recall people writing to the forum wondering why a commercially available controller wouldn't work with their Shopsmith. The reason is that those controllers aren't compatible with induction motors, they primarily work with universal motors. Variable speed induction motors do work with Variable Frequency Drives (VFD) but as far as I know those are three-phase motors and are specifically designed for the purpose.

Quite a few people have gone with some form of DC motor and DC controller. Shopsmith solutions include PowerPro or a mechanical Speed Reducer.

- David