"Joe" wrote:

We use some decent flat head screws on our units and I've run into a
strange
problem. When we tighten them into the aluminum housings, they hold a
galvanized plate in place. After about 10 minutes of being on there,
they
are almost impossible to get off.

We have turned the highest quality allen keys we can find into pretzels
and
have stripped many using impact and a shorter length. Sometimes we have
success by using a chisel to "spin" the flat head loose but that's the
Neanderthal method I'd like to avoid... Even that fails 50% of the time.
We can't use heat because there is a rubber seal in the aluminum very
close.

The flat head actually grabs onto the galv. plate so well that our
customers
(and us!) have to drill them out 8 out of 10 times we need to remove
them...

Anyone know of a super allen key or some other method of removing these
that
might work? We know that when we use painted plates, we have less of a
problem and have considered painting the countersink of each flat head
hole,
but that's crazy in the big scheme of things...

Thoughts, wisdom and random visits from friends welcome.

You appear to have some sort of bonding process going on between the screw
and the parent material.

1) Use TORX screws instead of allen screws. You can apply significantly more
torque without rounding off the fastener or the tool.

2) Use antiseize or moly lubricant under the screw head.

3) Reduce the tightening torque.

4) Use an impact screwdriver to undo or give each screw a good belt on the
head before trying to undo it.

5) Consider the electro-plating of the screws with respect to the parent
material. A different finish might resolve the problem.
--
Dave Baker - Puma Race Engines (www.pumaracing.co.uk)