South Bend 9" Junior - Spindle Speeds and Countershaft Pulleys

I tried to use the treadmill motor and one of those BC141 (Baldor) motor controllers so I could have variable speeds.  Unfortunately, that didn't really work out - with the motor controller and that particular motor, it didn't want to drive the lathe.  So, I had to set out to do this a bit differently.  I had on hand a number of 1725 RPM motors, and I needed to get the following speeds : 39, 64, 110, 208, 348, and 596 RPM.

I tossed together a quick calculator to generate the spindle speed, using a countershaft :

Motor RPM :
Motor Pulley Diameter :
Countershaft Pulley Diameter Driven by Motor :
Countershaft Pulley Driving Spindie Diameter :
Spindle Pulley Diameter :
Spindle Speed :

So far, to get close to the original speeds, I need :

a 2" motor pulley
A 5.75 " countershaft pulley
A 4-step pulley with the largest being a 5" pulley.

  spindle based on 2" step : 240
  spindle based on 3" step : 360
  spindle based on 4" step : 480
  spindle based on 5" step : 600

If I change the 5.75" countershaft pulley to a 10" pulley, it would then give me :

  spindle based on 2" step : 138
  spindle based on 3" step : 207
  spindle based on 4" step : 276
  spindle based on 5" step : 345

That's still not slow enough.  Moving to a 10" pulley and a 1.5" motor pulley puts me at :

  spindle based on 2" step : 103.5
  spindle based on 3" step : 155.25
  spindle based on 4" step : 207
  spindle based on 5" step : 258.75

Which is still three times as fast as it should be.

If I add a 1.5" pulley on the countershaft to drive the spindle, I get around 77 RPM.  That is about twice as fast.  That is getting there.  If I change the motor pulley for a 1.25, and add a 1.25 pulley on the countershaft to drive, that gets me to about 53 RPM, which is close enough to create my own pulleys.  So, that "close enough" would be done with :

2x 1.25" pulleys
1 2" pulley
1 5.75 " pulley
1 10" pulley

That will do!