Atlas/Craftsman Lathe Motor and Countershaft Pulleys

[wa5cab]

I would agree with you about the key and keyway. But on the other hand, in the 40+ years that I have had my 3996, the larger pulley has never moved on the shaft. Which is not true of the motor pulley. I used to have to loosen the set screw and slide it back onto the motor shaft at least once a month. I finally bought a split collar from Mcmaster, repositioned the pulley on the motor shaft, and installed the collar on the shaft up hard against the pulley. Since I did that, the pulley has never moved again. I probably did that 5 or 6 years ago. So I think that I would recommend leaving the larger pulley as is.

 

[kcoffield]

Got them installed. I didn’t key the larger pulley or balance it. Just installed it same as the original. Both pulley combinations tension the same and it seems to run nicely. I’m going to call this one a wrap.



Best,
Kelly

 

[wa5cab]

Looks good. I would suggest that you go ahead and buy from McMaster or whomever a 5/8" split collar and install it on the motor shaft up against the motor pulley and the end of the square key. Then you can just forget about it.

 

[kcoffield]

I used to have to loosen the set screw and slide it back onto the motor shaft at least once a month. I finally bought a split collar from Mcmaster, repositioned the pulley on the motor shaft, and installed the collar on the shaft up hard against the pulley. Since I did that, the pulley has never moved again.

I thought I understood this when you said it but now I'm not sure. With the 2-step drive pulley I don't have enough shaft length for a collar in a addition to the pulley. What type of split collar bushing and how where did you install it?

Best,
Kelly

 

[wa5cab]

I simply slipped the split collar onto the motor shaft. But I would guess that my 3/4 HP 120/240 VAC motor must have had a longer shaft than yours. Or possible the motor pulley is moved to the right farther than yours is. Which would mean that my countershaft pulley was farther to the right or my motor was farther to the left. And/or maybe I moved the pulley to the right, shortened the key so that it's left end was flush with the left face of the motor pulley, installed the collar and then slid the motor to the left to get the motor pulley back into the same plane as the countershaft pulley. Try the latter procedure and see whether or not you can get a stock split collar to work. I think that I had to grind a little bit off of the side of the square key that is in the keyway in order to get it to allow the pulley to slide freely a little closer to the motor. But I have slept a few times since I did it. The split collar is of the 2-piece style, with two socket head cap screws both inserted from the same side of the collar. There is about 1/8" of the motor shaft sticking out from the collar. And like on most motor shafts, the keyway is cut with a horizontal mill type cutter, not with an end mill. So the key way gets shallower near the motor end bell and bearing. The motor was made by Baldor but I don't think that there was anything special about it.