If you have some shim stock (feeler gage), it should be adequate for your HP
and load requirements. Use Loctite between the shim and pulley, if you'd
prefer to.
I did this recently for a nearly identical application.
The .005 runout would be problematic, in my opinion.

WB
.................

"Ed" wrote in message
om...
I'm going to replace the AC motor on my Lathemaster 8x14 lathe with a
DC treadmill motor as I want varible speed. (I checked & can't find a
3-phase motor that small, otherwise I'd use a VFD).

Anyway, the original 1 HP motor has a 16mm keyway shaft (0.630") and
the new DC motor has a 5/8" (0.625") keyway shaft.

How do I deal with the 0.005" difference? Is 0.005" within the normal
tolerance range for pulley ID's and I can forget it? Or should I
machine, split, and press fit a very thin bushing into the original
pulley set? I want to use the original pulley set as it includes a
timing gear.

Regards,
Ed Ferguson