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torquing procedure

alpinelakespilot2000

Well Known Member
Sorry if this is really a silly question--but I'm just learning how to use a torque wrench.

In Van's section 5 it suggests bolt shanks should be lubed. In my torque wrench instructions, it says the threads should be lubed. Both make sense to me, but since the nuts I am using with the AN3 hardware in the emp. all have the plastic/nylon inserts, would lubing the threads be counterproductive (i.e. will the grease defeat the locking action of the nylon)? Does Van's mean only that portion of the shank that is NOT threaded?

Also, for those who inserted the counterweight in the rudder already... I assume that even though it uses a AN3 screw/bolt, that this combination needs to be torqued as well (?).

Thanks a lot for helping with all this basic stuff.

Steve
 
Lubing bolt shanks is OK, especially if torquing from the bolt head. But I think oiling the threads in not a good idea. It may cause you to overtorque the bolts. Maybe someone more knowledgable can comment. I pretty sure the threads need to be dry.

Roberta
 
Guys... as always, the FAA AC 43-13 document is the guide (the "bible").

AC 43.13-1B ACCEPTABLE METHODS, TECHNIQUES, AND PRACTICES - AIRCRAFT INSPECTION AND REPAIR

Torque aircraft nuts and bolts dry.

Measure the friction drag torque as the nut is being run down, and add this to the torque value from the applicable torque value table to arrive at the value you set into the torque wrench.

The applicable chapter is here in a Word format..
http://www.faa.gov/certification/aircraft/av-info/dst/43-13/Ch_07-03.doc

The entire document is here, listed by chapter headings.
http://www.faa.gov/certification/aircraft/av-info/dst/43-13/default.htm

This is for airframes, check the Lycoming documentation for engines...

:) Happy torquing gil in Tucson EAA Technical Counselor
 
Thanks Gil, I need to get a copy "the bible."

That said, how do you know what the "friction drag torque" is if you have a ratcheting torque wrench? On a dial wrench you could read the force as you're twisting the nut down, but you don't have this luxury on a ratcheting (or "dial-less") wrench. Am I missing something (probably obvious) or is there an alternate way to know how much to add to the wrench setting to accomodate the "friction drag torque"?

Thanks.

Steve
 
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