cutting a half moon keyway

David,

Unless you have a milling machine I'd forget the half-moon (Woodruff) key and go with a straight square key.  It is reasonably easy to cut a keyway in that shaft using a good cape chisel.  That's the way it was done before milling machines and it still works.  A 3/16″ key would be appropriate for that size shaft, though you could use 1/4″ if you had to.  I think you'll find that most 1″ bore sheaves have a 3/16″ keyway, though.

Pick up a 3/16″ cape chisel from a hardware store or, preferably, an industrial supply.  You'll want to get a good one, not a cheap Harbor Freight one or you'll drive yourself crazy having to sharpen it every three cuts.  Take shallow cuts, just enough to peel a sliver up, until you get the trough properly established and then yu can be a bit more aggressive.  You want the finished keyway to be just a couple of thousandths more than 3/32″ deep.  Takes me about twenty minutes to cut one that way, and I've done dozens of them over the years.  I find it easier to do that than to horse a heavy motor up onto a mill table.  🙂

Unless the shaft has a step, or is tapered, a locknut on the end won't do much for you.  But most sheaves have one or more set screws that tighten onto the shaft, usually one of them indexed over the keyway.  If you're not planning to really load the sheave heavily, you can cheat and just drill a dimple(s) in the shaft to accept the end of the grub screw (British term for set screw).

They make taper lock hubs for this kind of thing.  The piece with the outside taper as a split down the length of it.  That part goes on the shaft.  The piece with the taper on the inside mounts to the pulley and slides over the other piece on the shaft.  Bolts around the periphery pull the two pieces together and squeeze the shaft piece tight on the shaft. 

I know about this because I used one on the electric car I built.  Believe me, once it's on there you're not getting it off again.  MUCH better than a Woodruff key.

I'll take a keyed shaft over a compression hub any day.  A keyed hub can pretty much always be removed later, but if a compression hub slips a bit under load it can and will weld itself to the shaft by friction galling and have to be cut off with a torch.  Seen it happen.

taper lock hubs are used on machines where large horse power motors are used. In 25 years of running and repairing machine have i ever seen one slip that was installed correctly. The taper has a great amount of force that is applied to the shaft. 

All of the tapered hubs I've ever seen use keyways. The hubs have threaded holes to be used with “pusher” bolts for dissasembly.

next to the threaded holes to remove the taper there are through holes that are threaded into the hub that pull the taper into the mating taper to lock on the shaft. Full diameter with the wedge of the taper holds a huge amount of force and can be used to with horsepower that the shaft can handle.

Mike

This is what Mike and I are talking about.