how to torque Inaccessible nuts

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stevewiz
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how to torque Inaccessible nuts

Post by stevewiz »

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.
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captain_john
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Post by captain_john »

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.

:wink: CJ
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bullojm1
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Post by bullojm1 »

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.
Mike Bullock
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stevewiz
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Post by stevewiz »

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.
RV-7 N71SW reserved
Started on 10/8/2013
Working on Fuselage as of 5/10/15 95%done
started finish kit on 7/1/16
engine on order from Barett.Will be shown at their EAA booth and then delivered to us after show

RayInGA
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Post by RayInGA »

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.
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bruceh
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Post by bruceh »

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!
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TomNativeNewYorker
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Post by TomNativeNewYorker »

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.

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captain_john
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Post by captain_john »

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
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captain_john
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Post by captain_john »

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.

:wink: CJ
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