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oups.com...
| I make spinning tools for a lady who owns a sheep farm. They look like
| a long slender top with a 3/32" drill rod shaft and a 1" diameter x
| .100 thick brass flywheel to generate the needed inertia to keep it
| spinning. These are for spinning cotton fibers.
|
| The problem is that some of them do not stay fixed in the hole. The
| hole is drilled and then reamed .0005 undersize and then the brass is
| tapped onto the shaft using another piece of brass the same diameter
| with a hole drilled in the center for the shaft to pass through. I
| think some of the brass is being displaced by the much harder steel
| shaft and it will spin on the shaft.

For the existing shafts, would the customer object if you installed a
roll pin on the shaft, flush with the flywheel? If you were to slot the
flywheel slightly narrower than the pin, you could also have a mild
interference fit, keeping it from sliding on the shaft. Swage the slot over
the pin and it's now permanent. You didn't state whether the shaft goes all
the way through the flywheel, but it would be good to use two pins if that
were the case. I had a similar problem, but on a much bigger scale, and
that was the simple only solution at the time.
For futures, why not thread the shaft into the flywheel? Throw in a
little locktite and it ought to hold great. You might have to retemper the
drill rod to tap it, though. Not sure how to work with that stuff.