I'm about to install a pair of fittings for a wing spar attachment. Two bolts hold the pair to the spar. I can't find instructions regarding torque. I'm wondering if I should follow this chart from RV group https://www.myrv10.com/tips/hardwareID.html

Any thoughts? Are you using a torque wrench? Just make them snug?

Thanks!

John C

I did not check the chart for errors but if those numbers are good, yes you can use it. Haa! how helpful was that.

Yes I did use a torque wrench. If you need to buy one look for one with a 1/4 inch drive that will work at the tiny torque these tiny bolts we use need. And preferably marked in in/lbs.
Now to really muddy the waters, and I may be wrong, but when bolts go through wood like we are doing we take the torque specs with a grain of salt. What I do is try to meet the torque spec  but stop if the wood shows a hint of crushing( the washer against wood, or bracket against wood, will begin to sink in a little).

OK I just looked it up for you in AC 43.13

10-32 bolt (same as an3) 20-25 inch pounds when using "normal nuts" and 12-15 inch pound if using the low profile sheer nuts.

1/4-28      50-70 inch pounds or 30-40 using sheer nuts

Thanks flydog. I'll be going for 40 inch pounds on AN4 bolt with AN365 nut. Oh, to get one thread to show, I need to use either AN4-17A (plans say AN4-16A) or AN364 nut. The AN4-17A, though, is really close to the last thread showing, so might need a washer.

John C

I do feel the Ison plans are very well done but yes, some of the bolt lengths they call out are suspect. I cant recall which ones now but -17 does sound familiar.

I installed brackets to root of forward and aft spars. Used -17's with a washer under the nut. Used 50 inch pounds.

John C