[rgmwa]

There are a number of flight-critical items such as the rudder and stabilator hinge brackets that are held in place with small AN3 bolts screwed into nutplates. The plans don't call for it so I assume it isn't necessary, but is anyone using Loctite on the threads?

 

[terrykohler]

Nope

Every nutplate you install will be a "prevailing torque" or locking type. Using locktite would serve no purpose other than destroy the proper on/off torque. These plates are formed by stamping, and the barrel is precisely squeezed to make the locking element. Typically, the standard for measuring this type of lock is first on torque, first off torque, and fifth off torque. Locktite is an adhesive and really shouldn't be re-used without cleaning the threads and re-applyng.
Terry, CFI
RV-9A N323TP

 

[rgmwa]

Typically, the standard for measuring this type of lock is first on torque, first off torque, and fifth off torque. Terry, CFI
RV-9A N323TP

Thanks for the quick reply Terry, although I'm not sure what you mean in the sentence above. Would you mind explaining?
Thanks.

 

[terrykohler]

All the Fasteners are Made to Performance Standards

Robert:
Whether it's a nut plate, an all-metal locknut, or a nylon insert locknut, there are manufacturing and performance standards that ensure that they function correctly not only in terms of strength, but also in terms of torque performance. The latter is tested by running the fasteners together in a test jig and measuring the torque needed to overcome the locking feature (1st on), and then the removal torque needed to disassemble the joint (1st off). The same fasteners are cycled on and off until the 5th removal, which is also measured. This ensures that the lock is still working properly after repeated use. Adding locktite to a joint that already has a mechanical lock may make the joint hard to disassemble or even cause you to overstress the fasteners. Bottom line, make it to plan and it will work as it should.
Terry

 

[Jetguy]

Nut plates are like lock nuts

Robert, what Terry is trying to tell you is that nut plates act like lock nuts. Try to hand screw a screw into a nut plate and you will see that it requires a certain amount of torque and will not easily unscrew.

 

[rgmwa]

Terry and John,

Many thanks for the clear explanations. I'm always impressed by the knowledge that forum members have and their willingness to help a new builder like me. Much appreciated.

Robert