Since I work alone, I didn't have anyone to eyeball the horizontal alignment
while drilling the wing pins. My solution was to hot glue a line level onto
the top of the electric drill temporarily. Watching the bubble allowed the
hole to be accurately aligned horizontally. Drill sizes used were: 1/8, 1/4,
and X. Heating of the bit was not noted with any of the drills -- apparently
the aluminum conducts the heat away nicely.
In tapping the lift pin holes, care must be used to keep the tap aligned; I
removed the tap wrench every turn or so and checked with a level as best I
could and also sighted down the tap to verify fore and aft alignment. Because
the aluminum is relatively soft, it is possible to mis-align during tapping
even it the hole was drilled perfectly.
In drilling the holes for the flap drive pins, I put the wings on the bench
upside down to allow gravity to maintain the flaps in the retracted position
and avoid interference between the bench and the flap hinges. The wing root
was raised using foam blocks until the spar pins were level and then the flap
drive pin holes were drilled horizontally using the method described above.
John A044 Newtown, CT
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