threadlocker and nylock nuts

[cnpeters]

Can threadlockers (Loctite, Threebond) be used with nylock type nuts? I wish to enhance the security of the elevator counterweight fastners.
Thanks

[DanH]

Threadlocker will work on any metal-to-metal thread, which is certainly found in a nylock nut.

Dan

[Captain_John]

It will work just fine.

It will make you feel better about the security of the fastener.

It is not necessary, at all.

Really smart people have designed these fasteners to perform for a lifetime with no maintenance whatsoever and so long as they are installed in accordance with their design parameters. That goes for rivets too!

Properly installing these AN365's does not include loctite according to "the book of standards". Van sells this book.

It says that these nuts shall be torqued with dry, clean threads, soooo one could argue that loctite would provide lubrication which could LEAD TO overtightening!

Soooooo, does this help?

CJ

[scard]

I didn't use any (internal) thread locker on those counterweight nuts, but I did cover them with some epoxy and flox. Mine are never coming out unless the epoxy casing is ground out. That is how I dealt with the concern in that area.

[az_gila]

Originally Posted by Captain_John

It will work just fine.

It says that these nuts shall be torqued with dry, clean threads, soooo one could argue that loctite would provide lubrication which could LEAD TO overtightening!

CJ

It's not the preferred technique, but our company practices do allow you to add the loctite AFTER the nut is installed.

As an example, it is sometimes needed in optical assemblies when an adjusting screw needs to be set during calibration/alignment. When it is all aligned, loctite can be added to the thread and it will wick down and lock.... and it's good enough for fighter aircraft...

This might be the best technique if a "suspenders and belt" approach is needed...

gil in Tucson

[jcoloccia]

Originally Posted by scard

I didn't use any (internal) thread locker on those counterweight nuts, but I did cover them with some epoxy and flox. Mine are never coming out unless the epoxy casing is ground out. That is how I dealt with the concern in that area.

Ditto...I figured any repair serious enough to warrant removing the weights and a little epoxy removal is the least of my concerns.

[Leland]

If you check the torque some hours or days after tightening nuts holding the lead weights on, you will find the torque value reduced. This is because the lead metal deforms under pressure over time, which is called creep. For this reason, my fasteners were covered with ProSeal, but epoxy with flox would work just as well. If a bolt came loose on the empennage, it could jam the controls.
Leland
RV9A 140 hours