Doing a little work on old Cessnas for fun these days and have to tell you I
don't like Phillips head screws. The slightest corrosion and they stick
and freeze. Then your Snap-On screwdriver (make sure it fits) wallows the
head out, as you grunt and cuss. Then you have to pull out the old die
grinder and disc a groove in the dam* thing and go pull out your common
screwdriver.

I have found that most stuck screws are as much the result of too much torque
on installation as corrosion, I mean a combination of both. If the initial
torque was not too high than removal is no problem even if there is some
corrosion.

If I am removing screws on a plane I haven't worked before I set the torque on
my battery screwdriver to a low setting so that it starts racheting before it
cams out of the screw head. If a screw is stuck then I progressively ramp up
the torque on the driver and often that will get a screw out. For the really
stubborn ones I get out my Craftsmen speed handle, I have the one with a really
wide handle that I sometimes will actually lean on with my chest. Anyway I
take the speed handle and try first to tighten the screw. If the screw is
stuck from corrosion than sometimes tightening will break it free and allow it
to be removed. If the screw is well and truly stuck I can judge when the bit
will cam out much better than with the power driver.

If the screw head is buggered up then very often a little valve grinding
compound will allow the bit to get a better bite. Snap On makes replaceable
bits that have serration on the removal faces that grip better than standard
bits.

If the screw won't come out either from being stuck or because the head is to
damaged then I will use a screw removal tool of some kind. I own several
types. I almost never use the die grinder disc technique and how to you use
that on a flush head screw anyway? Sometimes, especiall on smaller screws #8
and #6 the head break off even when you use all techniques and the only thing
left is to muckle on to the stem of the screw with vise grips and twist it out,
providing you get all the other screws out so that the cover is removed and the
body of the srcrew is accessible. Sometimes I will get on the underside of the
stuck screw and continue to tighten it until the headless screw comes out the
bottom, this is not possible if the screw is in a blind area of course.

In any event once I have gone through the procedures of stuck screw removal on
one annual of a new to me aircraft I rarely have any more problems from stuck
screws because I do not overtorque them on installation. I will also squirt a
light oil into the female fastener if I think it is necessary.

I suspect that whether you are dealing with torx, hex or square drive, phillips
or reed and prince, quad wing or tri wing, every type of fastener style has its
pros and cons.

John Dupre'