P12-D conversion to 78 RPM

[Nuclearfirebox]

I am interested in creating a 78 rpm PL12-D. I believe an easily reversible way of doing this would be to have a new spindle made with a diameter of 0.87cm. I base this on a pulley conversion of 1800rpms (@60 cycles) for the motor (is this correct?) and a platter pulley size of 20 cm.
This new spindle would replace the existing unit that is on the motor shaft.
If this works I could then create a spindle of 0.37cm and 0.87cm to allow the use of the lever arm to switch between the two.
Any other thoughts on how to convert the PL12-d to 78 rpm use?

[gridleakrick]

Yes, that would work. But I would suggest making your pulley diameter measurement to at least 3 places past the decimal point (i.e.-to thousandths of an inch). Then machine the new pulley a little bit large and file or sand it down to the correct speed using a strobe disk since you have no other way to control the exact speed on this turntable.
Rick