[Beowulf] Drive screw fixed with LocTite

[David Mathog]

Mark Kosmowski wrote:

> Blue Loctite is removable with just a little more force than needed
> with mechanical lock washers.  It is critical to get a good, solid fit
> with the tool to the bolt / screw though.  Were you using the correct
> driver or just one that fit "good enough"?

It was the right tool.  For a tiny Philips head screw which has been
fixed with LocTite the problem is that the force that will cause the
indentations in the head to fail is perilously close to the force needed
to turn the screw.  It did not help that the screw was definitely not
made of the hardest steel.  In order to get the screw out in the end the
disk had to be stood on its side and substantial downward force applied
to the screwdriver to keep it from jumping out of the grooves while it
was turned.  The initial attempt to remove the screw had already damaged
the head somewhat - because normal force did not turn the screw, and the
screwdriver jumped back and chewed up the head a bit.  By that I mean, I
stuck the screwdriver in, applied as much force as one would normally
apply, and rather than the screw moving, the screwdriver rode up a bit
in the groves and damaged them.  Had I been using a power screwdriver it
certainly would have completely stripped the head on the first attempt,
because one would not normally apply as much force as was required along
the axis of the screw.

Regards,

David Mathog
mathog at caltech.edu
Manager, Sequence Analysis Facility, Biology Division, Caltech