Spar bushings

[gmackay]

Ok, what size are the bushings in the front spar for the strut attach fitting? I thought I heard they were 7/16" but mine are larger than that. Mine are .462" which is larger than 7/16" but smaller than 15/32".

So how is everyone drilling this?

[crispy critter]

Re: Spar bushings

Greg,
We drilled ours with a drill bit and a drill.. ......Sorry,I couldn't resist that one.

[gmackay]

Re: Spar bushings

OK, I left myself wide open for that one................what size bit, what size bushing?

[mulwyk]

Re: Spar bushings

Well, I don't remember what size bit I used, but consider this: Your bushings are .462? You'll need at least .002 clearance to get the bushings into the hole...so you'd need at least a .464 hole. But don't forget you need to coat the inside of the hole with varnish...say .002 varnish film on each side of the bushing, .004 total. That brings your hole size up to minimum .468. Real close to a 15/32 (.46875) drill bit.

You need that varnish in there to seal the wood fibers inside the hole and avoid rot when the spar gets wet. The varnish also serves to "glue" the bushings into the hole in such a way that the next guy that rebuilds your wings can still easily remove them. (An old boatbuilder trick!)

Bob Gustafson