Went ahead and set up the Unimat One headstock with the Harbor Freight two inch
three jaw chuck and crank bolt about thirty degrees off vertical. Whatever the
slope of the jaws steps was...

But when the shafts face each other, things tend to unscrew! So I tightened it
all down more than I liked to, and it came out. Then I filed the bolt in the
drill press.

The stone drives the work and since it's at an angle, cuts it, too. It's easy
to build up speed. At speed, the slightest finger drag causes high deceleration
from inertia and it unscrews. So you have to modulate your finger drag very
carefully to see it never gets going real fast, just fast enough for a nice
even feed, and consequentially, concentricity and circularity.

The way they work is, the inner radius is smaller than the radius of the dust
cap, so the small torque transferred at the bolt is opposed by large torque.
Also, the bolt torque is dynamic friction and less than the static friction at
the cap.

They work great now.

I could go into business making these for Harris, who supplied the too closely
matched parts, hand selected from what appear to be stock parts.


Yours,

Doug Goncz ( ftp://users.aol.com/DGoncz/ )

My physics project at NVCC:
Google Groups, then "dgoncz" and some of:
ultracapacitor bicycle fluorescent flywheel inverter

4-1-9 Fraud
http://www.secretservice.gov/electronic_evidence.shtml