The lathe is a circa late 1945 South Bend 9a with undermount drive. The table is a custom made stainless steel table. In forward the belt runs centered at about 1/8 inch toward the tail stock, in reverse the belt is centered.
If when running in forward and back gears engaged I firmly, but not straining, put a load on the spindle the belt walks off the counter shaft toward the tail stock. When in reverse the belt runs off the spindle pulley toward the left, away from the tail stock.
The belt is an accu link size B 5/8. When running without load it is relatively smooth and quiet. However due to the construction there is some ability for the belt to distort. It is not immediately obvious to me why under load there would be a preference to distort in one dimension over another. (Whatever belt that goes on this lathe has to be spliced. The pulleys are fully encircled by the pulley mount casting. There is no way to mount a continuous belt.)
The table is solid and firm. The motor mount is well secured and stable. I am skeptical of the mounting system distorting under load as the first suspect. However I have to say that is where I am inclined to start.
I would appreciate any input on this.
Thanks Dan.
If when running in forward and back gears engaged I firmly, but not straining, put a load on the spindle the belt walks off the counter shaft toward the tail stock. When in reverse the belt runs off the spindle pulley toward the left, away from the tail stock.
The belt is an accu link size B 5/8. When running without load it is relatively smooth and quiet. However due to the construction there is some ability for the belt to distort. It is not immediately obvious to me why under load there would be a preference to distort in one dimension over another. (Whatever belt that goes on this lathe has to be spliced. The pulleys are fully encircled by the pulley mount casting. There is no way to mount a continuous belt.)
The table is solid and firm. The motor mount is well secured and stable. I am skeptical of the mounting system distorting under load as the first suspect. However I have to say that is where I am inclined to start.
I would appreciate any input on this.
Thanks Dan.