I've had a set of Amber rear turn signal lenses for a decade or more, so
I decided it might be about time to put them on. Wouldn't want to rush
or anything.
These are inside screw lenses, so a screw must be threaded into the
holes in the bosses. These taper a bit, the holes measuring around
0.128 (#30) at the top, and around 0.120 (#31) at the bottom.
Heeding Al Johnson's warning about cracking the bosses, I decided to
find a screw that would barely fit into the holes. A 6-32 looked close,
and it measures about 0.135 peak to peak on the threads.
My tap set says to drill 0.106 (#36) for a 6-32 tap, so it appeared that
the tap would make some shallow threads, probably without much stress.
It worked as predicted, and the screws seem to have a good enough
foothold in the plastic.
Stu Brennan
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