Castellated Nut Torque Value?

[Dbro172]

Im bolting my flaps to the wings and come across my first castellated nuts / cotter pins on the project.

I have not found any specific information pertaining to the torque value for the castellated nuts.

Based on size, are the castellated nuts to be torqued to the same values as the standard AN bolt / locknut combination (say, 20-25 inch lbs. for an AN3, etc.)

Thanks

[Rick_A]

The final values are the same, but you also have to be able to get the slots in the nut to line up with the hole in the bolt.

Start with the torque at the low end of the range and check to see if you can get the cotter pin in. If not, continue to torque up to the maximum torque but DO NOT exceed the maximum.

If you were not able to get the cotter pin in anywhere between the min & max torque range, add or remove washers and try again.

[jrs14855]

Those are not castellated nuts they are CASTLE nuts.

[curtis]

http://www.merriam-webster.com/dicti...tellated%20nut. .

Who cares?! Castle, castellated, nutplate, platenut???!!!

[GAHco]

Across the pond I have seen them called crown nuts.
Not important, just a little trivia.

When was the last time you saw a self-locking castellated nut? What torque?
Hawker uses them. What I want to know is why a cotter pin secured nut needs to be self locking. Maybe it should also be drilled for safety wire.

[jwyatt]

Leaving aside the issue of what they're called...

If the nuts in question are the 3 per flap that secure the flaps to the hinges below the wing, I don't believe they are torqued to the standard value -- they are there simply to act as a pivot point for the flap's up/down motion. Torquing them to the AN value would cause the hinge to be very difficult to move...bad for the flap motor.

I put the nut on finger tight, then backed off until the previous slot aligned with the hole in the bolt. Insert cotter pins, then test to be sure the motion of the flap is smooth and not binding. You'll come across the same thing when connecting the rudder cables/pedals.

[az_gila]

Originally Posted by paul mosher

When was the last time you saw a self-locking castellated nut? What torque?
Hawker uses them. What I want to know is why a cotter pin secured nut needs to be self locking. Maybe it should also be drilled for safety wire.

Actually, quite often, and I bought a few from Spruce for critical applications...

http://www.aircraftspruce.com/catalo...es/ms17825.php

[Dbro172]

Originally Posted by jwyatt

Leaving aside the issue of what they're called...

If the nuts in question are the 3 per flap that secure the flaps to the hinges below the wing, I don't believe they are torqued to the standard value -- they are there simply to act as a pivot point for the flap's up/down motion. Torquing them to the AN value would cause the hinge to be very difficult to move...bad for the flap motor.

I put the nut on finger tight, then backed off until the previous slot aligned with the hole in the bolt. Insert cotter pins, then test to be sure the motion of the flap is smooth and not binding. You'll come across the same thing when connecting the rudder cables/pedals.

These were the three in question. I did end up torquing these to about 22 inch lbs. and there is no binding whatsoever; flaps swing freely. Remember, there is a brass bushing squeezed into the wing side flap bracket, (1/64" inch wider on each side of bracket) preventing a bind issue here.