SonexBuilders.net

I'm stuck on this. I've drilled up in small increments, the last being 1/64" and the resultant hole is about .002" bigger than the AN4 bolt. That's a nice fit if you ask me, it drops in but there is no slop....that's a "no slop fit". If I stop before this last drill (1/4"), the hole would be about .010 too small and that would take a 10 lb sledge hammer or hydraulic press to get the bolt in.

What is everyone else doing to get a light-tap-with-a-mallet fit?

Thanks,
Stuck-on-a-tight-fit-hole Darick

I have a set of numbered and lettered drill bits. Numbers 12 and 11 get used a lot for AN3 bolts (mostly number 12). Letter D gets used a lot for AN4.

Letter D is 0.246" which is the lower end of the 0.246"-0.249" range for AN4 bolts and tends to be pretty tight (possibly remedied by running it through a few times). 1/4" tends to fit like you describe. To me (a fellow builder who hasn't flown yet), your fit sounds great.

My understanding is Sonex doesn't require us to use reamers, but I know others have used them on these holes.

I would be happy with a .002 fit.