Mechanical question, using a set screw to attatch a cylinder to a bolt

NewJerseyTN

Basically I've got a universal joint that I want to use in between two parts of a robot.· The UV joint won't spin, it's just being used as a left/right and up/down·bending joint.· The UV joint has a hole at each end that you put a round shaft into.· The shaft is held in place by two set screws on each end of the UV joint.· But in my design I will have the ends of the UV joint against a flat piece of plastic.· What I would like to do is drill a hole in the plastic, put a small bolt through the hole, put the UV joint onto the bolt, then tighten the set screws.· But I'm kind of worried about the threads on the bolt, that the set screws might not tighten down all the way.

Franklin

In most cases the set screws are harder than the bolt and you will damage the threads before the set screw. Since the bolt is just a mounting point it should not matter.

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- Stephen

James Newman

As said, with enough force you'll deform the threads and the setscrew will make it's own flat there-ish. If your really worried, put everything together, tighten the setscrew enough to mark the bolt, then remove the bolt and grind a flat in that location. If there is enough space, you can add a second setscrew behind the first to keep it from backing off. Finally if your really worried about it, add some locktite to the setscrew and your good to go.

NewJerseyTN

I went to Lowe's last night and I picked up some steel rod, aluminum rod, and I found some bolts that have a flat area before the threads start. The unthreaded area starts at the head and goes about an inch before the threads start. So I will probably use that for the connection to the plastic parts. I'm going to use the aluminum rod for any UV joint to UV joint connections. The steel rod wasn't actually the size marked (1/4"). It was plated so I think they listed the measurement before plateing.