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key in variable shive

Typical sheared key. Symptoms are slow to spool up to speed and loss of rpm when entering the cut.
Must be from a 1 1/2 hp mill. The 2 hp mill has a key that fits in a metal shoe. Check the
motor key too.
John
 
probably shear key as others have said.
.
i have seen where a brass key was replaced with steel and the shaft broke and since same shaft had spline gear teeth at other end, the whole machine was sent to scrap yard as remaking a custom hard to manufacture part can cost more than the machine is worth
 
Plastic used because its supposed to be run without lubrication. I've heard of folk using bronze bushes and bronze or steel keys but oiling makes horrid mess and not oiling wears the motor shaft. Paying for a new key and set of bushes every 5 to 10 years is much less painful than a new motor.

Nylatron or a combination of Nylon and Graphite. They have a little spud on back and not worth trying to make your own. They are also super glued in place. I use Loc-tite 380. Rich

#2 on that unless you have the original ones having formed in place bushes. Grooves in the pulley bore to hold bushes in place so you can't just stick new style bushes in and the key is a slightly different size too. 'horrible job. Almost worth buying new set of varidisks.

Clive
 
I just rebuilt mine (on my real Bridgeport 1-1/2hp, not a clone) using a kit from H&W. The bushings and key were plastic.
 
It would be 2 weeks at least to get a plastic one
Plus this is not a "real" Bport so who knows what to order. Made one from soft brass.
 

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I use a VFD for my machine, which slowly ramps up the speed after it's turned on. This avoids the normal starting shock a standard machine gets when turned on with a simple switch that instantly slams the motor with 3 phase 220 VAC. I'm pretty sure the reason for the plastic key is to help absorb the shock of the instant-on effect. It's also probably slippier and quieter than a metal key too, allowing the sheave to move up and down with less stiction. But if yours came stock with that, and it's still in good shape and there's minimal play when mounted, I wouldn't think twice about reinstalling it.

Here's a good H&W video on rebuilding the bushings:

 








 
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