U-joint problems

We have been using universal joints on our drive train, and they have a tendency to fall apart. The little pins in them come out and the piece splits in half.
I am interested to know if anyone else has experienced this problem. If not, I might try getting a new pack of U-joints to see if they work better.


This is definitely something people have said about the vex universal joints. I would recommend designing in a way where they are not necessary.

Yes the pins fall out even when lightly loaded. Our teams only makes reference to vex universal joints where sarcasim is expressed in the same sentence. You can however successfully use them as weights.

Darn. We have some u-joints but never made use of them yet. Sounds like it may not be worth trying. Seems odd they would be that poorly designed.

The pins are an interference press fit but once you start applying lateral load on them they just drop out. If the cross journal holes were a little smaller and perhaps a slight knurl on the end of the pin added as well these might become a viable part for something other than a hand cranked demonstration mechanism.

Thanks for the input. It definitely sound like we just need to find a different mechanism.
I found one thing that might help people using the u-joints with lighter loads. If you smash the pins back in with a vise clamp after they fall out, some of them stay in a little better.