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Shaft and Pulley Repair?

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  • Shaft and Pulley Repair?

    I've got a messed up shaft on a 1hp AC motor with a 5/8" shaft. The pulley is also worn and wobbles. It looks like a key was missing and the set screw was just cranked down as a hack repair. It is off a air compressor.

    My first thoughts are to bore out the pulley TIG weld in a new center, machine new hole and file cut keyway. It looks like it was a 1/4" keyway. I've got to file it because I don't have a broach for cutting keys.

    On the shaft I was going to machine it down sleeve it and recut key with an 1/4" end mill.

    Based on my scrap pile I've got some 5/8" 4130 for the motor shaft and 1" 1020 for the pulley.

    I've never done a repair like this before. Is there a better or more efficient way to do this? Any pitfalls i might be in for?

  • #2
    Why not just buy a new pulley? They are cheap. Unless it was something special.

    You can braze to the cast but you really are not going to tig to it. And I have never had real good luck with sleeves on pulleys.

    Take a file and clean up the shaft. Make sure you use a key and it will be fine as is.


    • #3
      I agree surplus center has a v-belt pulley about that size for ~$5, but isn't a standard v-belt. It a odd 6 groove belt. Kinda like a an automotive serpentine belt, but not. It has 390J6 on it and oddly enough it says it it "made in the usa".

      I agree brazing would be better on cast iron. It doesn't appear to be cast iron. It looks like it is mild steel. That why I feel that welding it will be ok.

      It looks like mcmaster has the belts. It is called a "J-section v-belt"
      Last edited by TIGer; 01-16-2012, 09:17 PM.


      • #4
        Is there a motor shop near by you that could put a new shaft in it for you???



        • #5
          Unless there is enough wear in the pulley to make it wobble excessively, a good cleanup with a new key, new setscrew and some JB weld or similar filled epoxy will likely make a permanent repair. Devcon and Loctite used to make adhesives just for that purpose and still do as far as I know. Heat will soften the epoxy if you need to take it apart later. If there is a lot of looseness adding a suitable shim to help keep the pulley straight while the epoxy sets might be in order.
          Don Young


          • #6
            If you machine the shaft down and sleeve it your going to separate your sleeve or most of it when you cut the key way.

            Since it's on a compressor....... I would make sure it's a good tight fit with no lash in it because the quick starts of the motor will eventually take it's toll on it again.



            • #7
              Then it is a poly-v belt.

              It could be steel then.


              • #8
                Buy or make a new Poly-vee pulley - dead easy to make.