"JJ" wrote in message
...
Has anyone had to specify or repair smaller
threaded holes (8-32) in
aluminum that have been heli-coiled? How about
the difference better
regular heli-coil and the "locking" heli-coil
that has the
circumference slightly deformed triangularly so
there is extra
gripping by those 3 sides with the fastener.
This sounds like a
pretty good idea and I wonder if it eliminates
the need for thread
locking fluid. There isn't a lot of vibration
or heavy load
(application is an industrial keyboard/control
panel)

The manufacturer seems to have specified
heli-coil (1 "diameter" long)
as part of the original design/construction
because of concern about
stripping out more due to the fastener being
inserted and removed
rather than the load being secured.

I'm curious to know if we'd be better off in
this application with a
stud going into bare aluminum (no heli-coil at
all) and probably using
an aggressive thread locking fluid. (red) This
way there would be
practically no insertion/removal in that
threaded hole, just the
torque/stress from removing the retaining nut.
(probably nyloc)


Threads in aluminum don't fare well in repeated
removal. Better to
use a stud or at least make an insert from an
annealed set screw.
I've made quite a number of these inserts over the
years and they
hold up much better than heli-coils. The smallest
ones I've made
were for 5 x 0.8 mm.
phil k.