Hi My lathe varies speed through a 2 pulley system one on the motor shaft and one one the lathe spindle. As you change the speed one pulley will open up reducing its diameter as the other pulley will close down increasing its diameter. There must be a name for this type of system but I don't know it.
My problem is the slowest speed is still too fast for the bigger blanks. Is there a way I can change the speed of the AC motor to compensate for the high ratio of the pulleys.
It's called a Reeves drive and the odds are long against being able to reduce the speed of the motor.
Possibly ... just possibly ... you could put the pulley on an idler shaft and reduce the speed that way. Probably far more effort than it's worth though ...that's why I have not done it on mine.
Pete, if you feel it's worth the work, like Bill said, it can be done. I think an "idler" would be like a clutch? Well, that's what Dell Stubbs did to his lathe in his bowl turning video. It's also an excellent video about turning so you'll get double info from it. : )
Try a foot switch for a sewing machine, you may have to cut the sewing machine side plug and relace with a standard plug. Tehse foot switch are usally carbon pile and can vary speed form extra slow to full speed on a
I doubt if that voltage drop controller will work. That sewing machine motor is probably something like 1/60Hp. I have serious doubts it can deal with the amps even a 1/2Hp motor will draw.
Sounds like my old Craftsman Variable speed 15". They are called Reeves drives. The bottom pulley slides along a shaft and "pinches" the belt to make it move in or out on the pulley. The upper pulley is spring driven and you have no control over that. The bottom pulley at some point will cease to contact the sides of the pulley and no longer power the lathe if you force the mechanism too far. My lathe allowed speeds between 400 and 2000 and I often found it too fast for really rough/out of round pieces.
As far as using a sewing machine pedal, variable speed switches only work with DC motors that use brushes. (an electrician can jump in and correct this if I am wrong). You'll probably blow the pedal but the smoke effects should be entertaining! Older sewing machines used heavy duty contact points (that was before the days of miniaturization) and on mine all I suceeded to do was fuse the heavy copper contacts together until the fuse box kicked out.
The easy answer to your question is therefore, no....unless you want to get into some jig building and using a second motor which you could use only until the piece is roughed out enough for the lathe's normal power drive to be turned on again.
Mike Courteau snipped-for-privacy@toymakersite.com
As a number of people have commented, you can't vary the speed of that motor. A speed control of the type used on a sewing machine or a fan speed control will only work with Brush type motors like a DC motor or a universal AC motor of the type used in electric tools like drills, routers etc.
There is another option albeit an expensive one, Replace the original single phase motor with a 208 volt 3 phase motor and run it from an inverter drive at 240VAC in. The inverter will electronically create thew 2 other phases and will vary the frequency of the power applied to the motor to vary it's speed. This is how the more expensive lathes like The Oneway, Powermatic etc with electronic spped control work.
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