Thanks, David - good advice.
I did try that, but apparently mine was too far gone:
too large a hole for the splines to bite into, even at max. torque of the
screw.

Jim

> For next time...just take the wiper arm and forcibly rotate it on the
> shaft.  That will wipe off the pot-metal splines and leave a smooth
surface
> again.  Dig the metal out from between the splines on the shaft with a
> scriber or safety-pin or similar, and reinstall the arm.
>
> david
>