Vibration in Craftsman/Atlas 101 12x24 lathe

JPMacG

JPMacG

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I have been chasing down a vibration issue on my Craftsman/Atlas 101 series 12x24 lathe. I think the vibration is coming from the large 2-step pulley on the rear pulley assembly between the motor and the lathe spindle. That pulley is bent slightly, so that it wiggles side to side by about 1/4 inch when turning.

I'm wondering what to do. It seems my options are:
1) Try to bend it straight, which may be successful but could make it worse.
2) Buy a used replacement Atlas pulley on ebay for around $60, which may or may not be better than what I have now.
3) Go to a variable frequency drive, and belt the motor directly to the spindle, removing the entire intermediate pulley assembly.

I'm not sure that 3) is even feasible, but it would be a neat solution if possible.

I welcome any thoughts or suggestions!
 
I would skip #1 (forget about straightening the pulley, might be possible but I wouldn't fuss with it.) You could make a pulley, someone here did that recently if I remember correctly. One of these days I'll make my own too because there is a little wobble in mine too. I'm keeping the pulleys even though I run a DC vari speed motor... really like the usable torque range with this setup.

2cents... :)
 
If the pulley hole is slightly larger than the shaft it may be cocking over to one side, especially if it is retained by 1 screw. Maybe just needs a shim to square it up on the shaft.

Cheers Phil
 
Thanks. I will check out the fit of the pulley on the shaft. That is a good thought. I also like the idea of the variable speed DC motor. I'll look into that as well.

The whole lathe vibrates noticeably, yet I am getting a nice surface finish and a run out of less than 0.001 inch on a 1.2 inch diameter, so I guess I should be happy.
 
The VFD would be a great option.

The last time I checked, Clausing still stocked the two-step pulley. They aren't cheap, but the new ones are much more rigid than the original spoked design on the older lathes. So that's another possibility.
 
Had the same problem with my 101 12x32 Atlas/Craftsman.I made a new jack shaft & bushings, problem gone, no wobble no vibration!!!


Dennis















Atlas/
 
If you find the pulley shaft hole is belled or oversize, square up the pulley and bore a new and properly aligned oversized hole and use a bushing to fit to the countershaft.

The original spoked pulley was very brittle after a time. You will not likely be able to bent/push the pulley back into alignment to the shaft. It will crack the spokes.

Another way would be cut out the hub and spokes and make a new center to mount the pulley onto. If you did this, you might as well make it all the way.
Pierre
 
I went with a 3 phase/variable speed setup with a 2 step pulley on the motor and a sliding mount that allow me to use all 3 belt sheaves on the spindle pulley. It works well, and I can reverse the motor which comes in handy when backing up the carriage without disengaging the 1/2 nuts. I can shoot you a pic if you'd like.
 
Yes, I would very much like to see a photo. Thanks! Are you sliding the motor in order to stay with the 2-step motor pulley that came with the lathe?

I tried to remove the large 2-step pulley last night. I would need a puller to get it off. It is definitely not a sloppy fit.
 
Likely dried out grease and grime plus that pesky setscrew indentation on the shaft is holding things on!
Pierre
 
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