yourname wrote:

Lurking here for a while absorbing a wealth of information from the
posters. Now it my turn to help. Thirty years ago it was common in
the motorcycle circle to remove flat head phillips screws from the
aluminum casting with a tool called an 'impact driver' (IIRC). It
was/is a 6 inch long device that would accept a 5/16" hex bit,
(phillips, slotted or allen) whatever you needed. Place it into the
stubborn fastener, apply a slight torque and smack the end with a
hammer. An internal cam provided more torque and the impact made sure
the bit stayed in the screw head. It was quite effective on the soft
screws Honda used to use to hold their cases togeather.
Got mine from Sears and believe Harbor Fright may have them too.
Hope this helps,

Jerry