[rayg]

I got a 1J head which did not have the motor.
Now got a 2 speed 50Hz motor which does not have the belt pulley.
Does anyone have the correct pulley or the dimensions of the 4 diameters.
I wont be using any VFD or such.
Thanks Ray

[Rich Carlstedt]

Ray , not sure of your specifications with the UK version of the bridgeport
maybe this can help, My BP is a J head, 1962 model 4 step pulley
Spindle Speeds are 660,1115,1750,2720 RPM
Motor is a 220 Volt 3 Phase 1745 RPM
Motor Pulleys are
3.20-4.600-5.820-7,000 as best as I can measure
I feel very confident with the 7.00" diameter and the spindle pulley is about 4.52 " at that diameter
It is difficult to accurately measure without taking the head-stock and motor apart
Good luck because if not right , it will be difficult to switch speeds and still tighten the belt.
I have no manual , so no help there
Rich

[rayg]

Thanks Rich,
Your speeds are a bit faster (UK 2400rpm/4800rpm top speeds on 2 speed motor) Your mains is 60hz vs UK 50hz but I am not exactly sure about the US belt ratios. I appreciate your assistance and agree that each step pair will need to have the same belt length. 7.0 is a good starting point.