Please keep in mind the differences in spindle register diameters between the Atlas and South Bend lathes. ?
?
While they're both are threaded 1 1/2-8, the spindle register diameter on South Bends is 1.510" (IIRC) while the Atlas is 1.500".
?
For best accuracy, the fit of the chuck's back plate ON THE REGISTER DIAMETER is very important. ?If you buy a 1 1/2-8 pre-threaded back plate,
almost certainly it will be bored to fit a South Bend spindle. This means you will have .010" clearance at the register diameter. ? This results in the plate being radially located on the spindle threads, and not on the register diameter. ?
?
I discovered this on my Jacobs spindle chuck which was bored to fit a South Bend. ?Had to bore out that diameter, press in a ring bushing, and bore it to 1.5005" to properly fit the Atlas spindle.?
