Worn keyway

Flip the shaft over and recut a new one 180 degrees off. It's what shapers do(or for that narrow, it wouldn't take long with a thin file). Or use a filled epoxy, JB Weld might work. I've used it on worn shafts with flats before. If you ever want to get it apart again, you might use some type of mold release on the key and hub...

Stan

Mill a new keyway on the other side of the shaft.

Use a roll pin in place of a square key. Prepare new keyway by mounting the fan without the key, and drill down the keyways with a smaller drill -- say a number 13 (.185") for a 3/16 (.1875) roll pin. Use a BFH to seat your new key.

There might be a way to fix them without machine tools but it's hard to guess without seeing the problem. Could you post some pix on one of the commercial sites (not here directly) like Picasa? You don't need their special software, the Basic Uploader works fine.

I know what jb weld is whats filled epoxy the key way isn't totally ruined only in the middle if i used one of those products and recut it do you think it would hold.

How would I get the drill bit that close to the shaft to drill parallel to the shaft

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regards Tim

Get a Climax shaft keyway cutter and cut the keyway over size and make a step key for it.

They show a video of it in operation.

Richard W.

Cut a new keyway 180 degrees off from the current one. Recut the keyways to the next size.

Do you think I could cut a new keyway with a file and exactly what type of file should I use. thanks

You have several good ideas for repair. You also need to install a setscrew over the key or otherwise tighten up the fit so there is absolutely no movement between the shaft and hub. Multiple setscrews or roll pins might be considered. Otherwise the same thing will likely happen again.

Don Young

Still no photos, plus we don't know what you have for machine tools or skills. A 'hand" or "pillar" file has parallel sides unlike the usual mill file, and a safe edge that lets it cut the slot wider without deepening it. But I think you'll find it extremely difficult to file the motor shaft key slot wider and keep the sides parallel and aligned straight with the keyway in the hub. Chances are when the new oversized key fits it will make contact at only a few places and will soon pound the slot wider.

This is the tool that cuts a keyway slot in the hub:

aren't cheap and you need a press, hammering is likely to break them.

If I absolutely had to do this without a milling machine, I would broach the hub to 3/16", chisel and file the shaft slot close but undersized, and then install the hub and tap in a 3/16" lathe bit to raise a chip at the edges of the shaft slot. The hub should guide the bit straight. File down the chip, tap the lathe bit in a litle further, file and repeat. I'd grind a sharp square end on the bit and then bevel the hub side slightly so only the shaft side cuts.

It's an easy job on a milling machine.

Jim Wilkins

Buy new pulleys with taper bushing hubs.

Loctite the new bushings to the shaft, but not to the pulley. The taper lock to the pulley will be fine, and leaving it dry with facilitate disassemble someday, if needed.

Forget the keyways.

This is something I have been wondering about since 3 months ago: do these tapered pulley bushings, if thouroughly tightened, require keyways at all or they can be used without a keyway?

Depends entirely on what you are driving, and if you Loctite them to the shaft.

He is driving a fan with an 1/8" keyway. I'm betting this is both a low horsepower and smooth transfer of power, and the it will work fine.

But if you drive something like a compressor with an electric motor, or a mower blade with a gasoline engine, you will probably, but not certainly need the key. In these examples you are driving a reciprocating load with a continuous source, or a continuous load with a reciprocating source. So the shock loading is a considerable factor.

He is driving a continuous load (fan) with a continuous source (electric motor), so I bet he will be ok. The only questions is, can is find a taper pulley for his shaft size. The 1/8" key makes me think we might be talking about a 1/2" shaft, and I don't know if they make them that small.

10 HP reciprocating compressor.

I did not use loctite, and I did use a little custom key that I had to make. (I had to bore the pulley hub, motor and hub have different keyway widths etc etc so the piece had to be custom shaped). I mae it out of regular mild steel.

possibly a lot of vibration.

Good point.

Might even be 7/16 shaft.