Electric motor shaft

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Old 11-01-17, 12:01 PM
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Electric motor shaft

I have a tablesaw with a three hp motor, the pulley must have lost its key way, and wore down the shaft. The pulley was not damaged but now it is too big for the worn shaft. Need to know how fix. Motor to replace is over three hundred dollars. I could grind down to 1/2 inch. But the pulleys I have found for this size do not have keyway. I don,t think a little set screw will hold this pulley to its shaft. Can I buy a sleeve to fit over the ground down 1/2 inch shaft to bring back up to original 5/8 and still utilize the keyway. To have someone replace the shaft I would think to be to costly. Of course I don't know. I am way out of my league with this, I have no knowledge in this area. I would appreciate any help. Can get to solve this problem, short of throwing a whole lot of money at it. Thanks for any advise,
 
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Old 11-01-17, 12:27 PM
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Your problem is that the motor shaft was not worn down evenly and I doubt you will be able to simply grind it down to 1/2" accurately enough. If you can have the shaft machined to be .500 and a keyway cut then you can use a shaft bushing. A larger than normal key will then bridge from the keyway in the motor shaft, through the spacer and to the pulley. All of this relies on precision so the parts don't slop around and quickly wear out so it's beyond using a grinder. It will have to be machined.



The other alternative is to weld the pulley onto the motor shaft. Depending on how much the shaft and pulley have worn it won't last forever but it can get you running for a while. Of course this means that the pulley and motor will never come apart again so in the future both will have to be replaced.
 
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Old 11-01-17, 01:11 PM
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I have used the split bushings and larger keys that Pilot Dane linked a few times while restoring older machinery, and they do work well, but you probably won't find them locally, so will need to go through a specialty house like McMaster Carr, Fastenal, Grainger, or someone like that, and will definitely need to have the shaft machined, not simply ground. If it happens to be a Craftsman or other common names, you might do as well checking Craigslist for a matching saw that you could buy for the motor. I have used Craigslist only a couple of times, but do look often enough to have seen that table saws are common there.
 
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Old 11-01-17, 08:22 PM
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Thanks for the feedback guys, guess I need to find a machine shop. I take it that changing out the shaft is something not to be considered?
 
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Old 11-01-17, 10:14 PM
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Changing the shaft means changing the motor. There is another answer but it is probably cost prohibitive. There are some machine shops that do metal flame spraying to build up shafts to then allow machining them to the original size. Many decades ago I worked in a facility that had numerous pumps that had worn shafts from the packing glands being too tight. We were converting the pumps to use mechanical seals and since they were old pumps new shafts were either not available or were ridiculously expensive with a long lead time. We were able to send them out to be sprayed and machined with less than a week down time. I don't know what it cost and I'm sure it costs more now.

The idea of checking Craig's List for a new saw is a good one. I see table saws on CL almost every day and asking prices from about $50 on up. I've seen some really nice cabinet saws with extended tables as well as cheap bench saws, all with fairly reasonable to very good prices.
 
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Old 11-02-17, 07:52 AM
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Another option would be to buy a replacement pulley with a smaller hole & have the motor shaft machined just enough to clean it up, and the pulley drilled to match at the same time.

Might find a used exact model motor on eBay for less money and bother.
 
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