Scott wrote: "...but I am bothered by the fine-thread pitch."

I agree, Scott - fine threads in aluminum, where the force in tension had to
be quite high (think botched cross-wind landing), gave me pause too. That's
why I had my redesigned main gear lower o/c link parts made of steel (re: my
earlier post) since the male threaded rod had to fit the rod-end bearing
female threads - which are NF.

Regarding the use of a Heli-coil insert in aluminum: If there's enough meat
in the female threaded part, a Heli-coil could be installed but it's still
be a fine thread since the Heli-coil insert, by design, has to have the same
thread pitch as the male piece screwed into it. Don't see where this changes
anything. The threads in the aluminum still must react the same loads,
albeit through the Heli-coil rather than directly.

In any case, whether I'm just overly cautious or not, I'll go with some
over-design in an area where being wrong can have such bad results.

Good flying,

Dan Schaefer