# RPMs



## dirty tools (Nov 30, 2012)

I just installed a new motor (240vac single phase) and datyon drun switch.
The lathe runs good for a 1916 SB.
I belive the RPM's. are to fast I could not find my meter to check.
Can some one recomened what should the chuck RPM's


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## Ray C (Nov 30, 2012)

Folks who own that style of lathe can hopefully provide info about what the set RPMs are supposed to be but, in-general, motors usually have a rating of around 1800 or 3600 RPMs.  Sometimes the range at the low end is 1700, 1750, 1775 or 1800 and at the high end is around 3450 to 3600.  If you put a higher RPM motor when the original was at the lower end then, things are spinning about twice as fast as it was designed for.  Probably not good for the machine.  In that case, you'll need to find a different motor or rig-in a 2:1 reduction (which is probably easier said than done).

Depending on the motor you have, it might be designed to be able to change the wiring to make it run at a different speed -but it's been a long time since I've seen a motor that can do that.

Ray


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dirty tools said:


> I just installed a new motor (240vac single phase) and datyon drun switch.
> The lathe runs good for a 1916 SB.
> I belive the RPM's. are to fast I could not find my meter to check.
> Can some one recomened what should the chuck RPM's


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## dirty tools (Nov 30, 2012)

OOPS

I should have ask

what size of pullies do I need ?

the motor rpm's is 1725 and I need to  run the backshaft at 250 rpm's


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## dirty tools (Nov 30, 2012)

I got my answer
http://temecularodrun.com/ref/rpm_calc.asp


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