how to torque Inaccessible nuts

stevewiz · Post by **stevewiz** » Mon Feb 02, 2015 10:45 am

What do you do when it is nearly impossible to get a torque wrench on nuts in certain places? Right now I am having a problem with the aileron hinge bolt and nut next to the flaps. Thanks in advance for your help.

captain_john · Post by **captain_john** » Mon Feb 02, 2015 12:17 pm

Don't worry about that now.you will need to take them off and put them back on again.

When you get to the point where they will be installed permanently, we can revisit this again.

There are calculations that take the arm of the wrench into consideration, but I think most builders use German torque methods.

CJ

Post by **bullojm1** » Wed Feb 04, 2015 10:18 am

Steve,

Sometimes a "Crows Foot" socket set is helpful in getting to hard to reach nuts. However, if you use an extension, the torque value you enter into the torque wrench will be less than the called out torque, only because an extension amplifies the torque given to the nut. Here is an easy to use calculator:

http://www.engineersedge.com/manufactur ... ension.htm

As CJ has pointed out, for some of there you can just "feel" what the right torque is and skip the wrench.

stevewiz · Post by **stevewiz** » Wed Feb 04, 2015 2:25 pm

Thanks guys, I thought the German method was "goodentight"
Anyway thanks again and I will visit this again in a couple of years if need be.

RayInGA · Post by **RayInGA** » Thu Sep 17, 2015 9:34 am

Also consider that castellated nuts can be install in place of self-locking. Finger tight and next castellation is what I have done on all flight control surface hinge points where the hardware is subject to rotation.

AC-43-13-1B

7-64. SELF-LOCKING NUTS. These nuts are acceptable for use on certificated aircraft subject to the aircraft manufacturer’s recommended practice sheets or specifications. Two types of self-locking nuts are currently in use, the all-metal type, and the fiber or nylon type.
a. DO NOT use self-locking nuts on parts subject to rotation.
b. Self-locking castellated nuts with cotter pins or lockwire may be used in any system.

bruceh · Post by **bruceh** » Thu Sep 17, 2015 11:36 pm

You'll get a feel for how tight to torque them. Take an accessible nut and practice with a torque wrench. Get it snug, then see how much farther the torque wrench takes the nut. Try it at both the max and min settings for the size bolt/nut. Do it several times, then put your wrench on the inaccessible nut and do the same. The smaller AN3 hardware doesn't take much effort to get it torqued. The "good-n-tite" is perfectly fine. Just don't over do it and snap the bolt in half!

TomNativeNewYorker · Post by **TomNativeNewYorker** » Sat Sep 19, 2015 8:33 pm

one way we did it was to torque the head side if it couldnt be done on the nut side. we would go to the high side. example, if the torque was 95 to 110 inch/pounds we would go to 110 and then cotter pin it. all our stuff pretty much is cotter pinned.

Use higher torque values for torquing from head end.
A tolerance of 10 percent above the higher torque
limit must not be exceeded.

captain_john · Post by **captain_john** » Sun Sep 20, 2015 7:45 pm

I was thinking about this thread as I was reading the October 2015 issue of Sport Aviation.

There is an article on this subject in it!

CJ

captain_john · Post by **captain_john** » Tue Sep 22, 2015 5:28 am

CORRECTION:

It was an article in a back issue... December 2013 with the blue and white Bearhawk Patrol on the cover.

Charlie Becker on page 96, Torque Values.

CJ