On 2008-01-26, Bob Engelhardt wrote:
I'm putting a new motor on my lathe that has a bigger shaft than the old
pulley. I'm planning on boring out the old pulley (another 1/8"), but
I want to make sure that this is not a Bad Idea before I do. Is it OK?

Well -- the first question is what will you use to do the
boring? I would want to do it on a lathe, taking the time to truly
center it in a 4-jaw chuck. (And I might use an old belt to fill the
outer V-groove so the chuck jaws are less likely to damage the pulley.

Just drilling it will probably cause the hole to be off center,
because of the keyway providing less resistance to the drill than the
rest of the pulley body. I certainly would not want to do it in a drill
press -- unless I had a piloted drill with just the right size pilot and
flute diameter.

So -- I hope that you have another lathe to use for the boring,
or a creative way to drive the exiting lathe while its pulley is not on
the motor. :-)

Considerations so far: there is plenty of meat in the old (cast iron)
pulley; the keyway will be reduced to 1/16" deep, but that should be
enough (?).

Well ... you can always use a keyseat broach to re-cut the
keyseat to proper depth (and possibly to a wider keyseat as well,
depending on what is standard for the size of the final bore.)

Good Luck,
DoN.

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