I'm trying to the the 4-40 sullivan gold clevis on a standard 4-40 pushrod but it seems to be very loose. It is the right threads but it threads on and off so easily and the result it a bit of slop. DOes anyone else use these and if so how do you tighten it up? I don't really want to put a drop of glue on it and I've tried to crimp it a bit but that doesn't work either....

Thx

Use 4-40 nut right behind it, and add some locktite to all thread contact area. Adjustment afterwards are tight and require 2 pliers, but it's worth it. Before I used this setup, the pushrods simply came off the clevises due to vibration while I run the engine on the ground. Now I have not detected any looseness.

Good luck!

I too use golden clevis' a lot and just use the threadlock/jamnut behind it method. I have not had one failure yet.

Dont try crimping them, you will just weaken the metal or make them worse!

I think that the real problem is that most 4-40 rod has rolled threads which are no where near as good (usually undersize) as machine cut or die cut threads.

Take a 4-40 bolt and compare them.

Andrew

Agree with post #2&3,also saved a club pilots plane couple weeks ago,plane was squirrely in flight.upon inspection we found the rods were metric and the clevis's were not, the fit was loose but under pressure the rod was moving inside the clevis.
Have a goodun,John.

Solder it!

No more problem, EVER with movement.

It's more of a permanent fix, but a great one none the less.

-Drew

I read your comment about rolled threads vs. cut, and have been of the impression that the rolled threads result in the threaded area being a bit larger than the rod itself. The reason being that no metal is cut away, rather it is displaced. I would think that cutting away the metal would leave threads the same size or smaller than the rod.

Is it possible you may have it backwards?

I agree that solder is the best,but if you use a jam nut,do not use a nylock nut,use a standard nut with loctite.I have never had one fail using this method.I find the nylock nuts are too hard to get tight against the clevis.
Mike

I only know what I know from my experience, and when I buy pre threaded rods (like Dubro) which use rolled threads, the rods are of a smaller diam. wire and the threads are raised by rolling, but are rarely the exact diam. It is a cheaper and less accurate method of making threads. If you take a good machine cut bolt the same size and mic it, its the "true" size of whatever UNC or UNF size you are using.

So, if you get a rod on the low end of the thread diameter and a loser than normal clevis you have a really sloppy linkage!

Thats why I normally buy my own wire, and use a 4-40 die to cut my own threads. Much better fits. trust me! (or buy a $10 die and try it)

AJC