drilled screws & low-profile self-lock castle nuts

[prkaye]

Does there exist a drilled version of MS24694-S67 (AN509-10R25)?

Also, does there exist a self-lock castle version of the low-profile nut MS21083-N3?

In Canada, we have to use castle-nuts and cotter pins on all fasteners around which a part rotates, so I need the above for my aileron attach hardware.

Thanks!

Phil

[az_gila]

Originally Posted by prkaye

Does there exist a drilled version of MS24694-S67 (AN509-10R25)?

Also, does there exist a self-lock castle version of the low-profile nut MS21083-N3?

In Canada, we have to use castle-nuts and cotter pins on all fasteners around which a part rotates, so I need the above for my aileron attach hardware.

Thanks!

Phil

...that on control systems too.

BUT - the center ball in the rod end does NOT rotate about the bolt. The ball should be tightly clamped between the sides of the control horn.

The ball in the rod end is the actual rotating part.

Is someone mis-reading the requirement, eh?

[vonjet]

So on a part with a rod end is it better to use a lock nut or a castle nut and cotter pin?
I have been very diligent in making sure I have castle nuts and cotter pins on all my control surface attachments even if the bolt goes thru a rod end.
Did I do all this for nothing? I hope I dont have to re-do all that hard work.

Bryan

[roee]

Originally Posted by az_gila

BUT - the center ball in the rod end does NOT rotate about the bolt. The ball should be tightly clamped between the sides of the control horn.

The ball in the rod end is the actual rotating part.

True. But that's when everything is working as it should. If the rod end bearing, through contamination, corrosion, whatever, starts to develop considerable friction, then the ball will try to rotate around the bolt. Of course we aim to never let it get to that condition. But just in case, whether required by the regs or not, castle nuts and cotter pins seem like good insurance. No?

[az_gila]

Originally Posted by roee

True. But that's when everything is working as it should. If the rod end bearing, through contamination, corrosion, whatever, starts to develop considerable friction, then the ball will try to rotate around the bolt. Of course we aim to never let it get to that condition. But just in case, whether required by the regs or not, castle nuts and cotter pins seem like good insurance. No?

...of history on this exact set up (lock nuts on rod ends) on certified planes.

The FAA (or certified manufacturers) has not deemed it necessary to change, and the use of a locknut/cotter pin only makes it harder to obtain the desired torque, and this holding power.

If the nut is even slightly loose, then the chances are that the bolt will become the pivot point, and will pivot about the thin material of the horn and wear out both parts.

No need to change standard practice, and Vans design...

[Mel]

You may use a drilled bolt/castle nut and cotter pin if you like, but if it is on a rod end bearing, it still needs to be "tight" just as if it were a nylok nut. You don't want the bearing rotating on the bolt.

[prkaye]

I actually didn't mean to start a debate about this. I agree teh requirement is probably not in the letter of the law, but our inspectors look for this, and the path of least resistance is just to do it. It can't hurt anyway. What I've done in other places is used drilled AN bolts and MS17825 self-lock castle nuts (they have the nyloc inserts). Kevin Horton (a local builder) calls this the "belt and suspenders approach".
Getting back to my question - I need to find (or make) those drilled AN509 screws, and find self-lock castle versions of the low-profile nuts (MS21083-N3)... anybody know if these exist?