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Need help with a Columbia AT

Posted: Fri Feb 10, 2012 2:44 pm
by Jerry B.
I am having trouble assembling the pulley and mandrel portion of my AT. When I tighten the nut on the far left, it introduces enough friction that the mandrel does not turn freely. When I loosen the nut so the mandrel spins properly, both the pulley and little gear spin on the shaft. There is no set screw on either the pulley or little gear. What am I missing here? Am I missing any parts? Any help would be appreciated. Thanks, Jerry Blais

Re: Need help with a Columbia AT

Posted: Fri Feb 10, 2012 8:28 pm
by phonogfp
Jerry,

I think you have all the parts. I ran into this problem years ago, and figured out that the washers must be in the correct positions. It's too long ago for me to remember the exact order, but the idea is to have the reverse-thread nut tighten the pulley onto the shaft by contacting the washers - rather than the casting. Try placing the small washer between the nut and the pulley. You'll get the idea!

Best,
George P.

Re: Need help with a Columbia AT

Posted: Fri Feb 10, 2012 11:03 pm
by Lucius1958
Just checked my AT, and the correct order is, from inside out:

Large washer

Gear

Pulley

Small washer

Nut


-Bill

Re: Need help with a Columbia AT

Posted: Sat Feb 11, 2012 8:30 am
by phonogfp
Thanks Bill - my memory's better than I thought!

George P.

Re: Need help with a Columbia AT

Posted: Sun Feb 12, 2012 10:31 pm
by Jerry B.
I appreciate the help but I'm still missing something. When I put them in the order that Bill suggests and tighten the nut, it pushes everything against the big washer and adds friction to the mandrel assembly. When I loosen the nut a little, the pulley and small gear spin on the mandrel shaft. How do I tighten the nut and not have friction in the assembly? If the small gear was fixed to the shaft and everything tightened against it, I could see it working. Thanks, Jerry

Re: Need help with a Columbia AT

Posted: Wed Feb 15, 2012 3:41 pm
by JerryVan
Try swapping the small washer with the large one in the order described above.

Re: Need help with a Columbia AT

Posted: Wed Feb 15, 2012 7:53 pm
by Jerry B.
Bingo!!! It works!!! It would never occur to me that the little washer should go first. Even when I was assembling it this way, I thought the little washer would just float on the shaft. Thanks to everyone for their suggestions. Jerry