View Full Version : Shaft and Pulley Repair?

01-16-2012, 08:44 PM
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?


https://picasaweb.google.com/lh/photo/tKhe0d1zxZH1O1q_gE998dMTjNZETYmyPJy0liipFm0?feat=d irectlink


01-16-2012, 09:01 PM
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.

01-16-2012, 09:12 PM
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"

01-16-2012, 09:20 PM
Is there a motor shop near by you that could put a new shaft in it for you???


Don Young
01-16-2012, 09:21 PM
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.

01-16-2012, 09:27 PM
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.


01-16-2012, 09:46 PM
Then it is a poly-v belt.

It could be steel then.

01-16-2012, 10:02 PM
Buy or make a new Poly-vee pulley - dead easy to make.