The very tops of the screw threads are knocked off cleanly. Either the
screw is undersized near the tip, the screw is REALLY soft, or your hole
was drilled oversized.

I'd try a REAL setscrew. These are black phospate covered, use an allen
wrench to tighten, and have a suitable point to dig in. The point is
sometimes called a "dog point", come in serveral flavors: you may find a
sharp point, a cup, or a star shaped arrangment that looks like the
character *

Any big box home store should have a display with small parts. Ask for a
'set screw'. Terrribly expensive if you need lots, easy to buy just one
for $.39 Buy a longer one so it has some meat sticking out.

My guess is that the set screw will hold in the bushing even though the
screw did not. But use the proper siced drill for your next experiment.

pogo wrote:

Thanks to everyone kind enough to help me with this!
Here is a (hopefully)better photo of the screw and also a somewhat blurry
one showing the penetration of the screw into the bushing where it stops at
the motor shaft flat. I hand tightened it on the motor shaft and slid it off
to show this.

Here's the latest link: http://www.waycoolgear.com/ebay/screw_in_bushing.jpg

When I screw it in more (with the motor shaft removed), it seems to bite in
and hold just fine without stripping at all.

I'll try to get even better photos if you guys think it will help more. Just
let me know exactly what you need to be of assistance.

Thanks !