Free rotating set screw attachment (like used in c-clamps)

[jwhendy]

I'm designing something in which an insert fits into a piece of steel square tubing. The insert is held in place by a set screw threaded in the insert, which is in turn loc-tited into an aluminum "plug" (wider surface area) and is clamped to the inner wall of the square tubing with a hex wrench via a hole in the square tubing which allows access to the hex head.

One thing I don't like is that the integral nature of the set screw/plug tends to want to move the tubing/insert out of alignment. As you tighten, the plug is pushing to the right on the tubing and wants to push the whole insert to the left.

This made me think of c-clamps and that "swivel head" on the end. See an example here.

Is anyone aware of a screw attachment like this? Essentially a swivel-end for a screw? This would keep my force normal and prevent this undesirable lateral force on the tubing/insert.

 

[Q_Goest]

They're called "swivel feet". You can get them through McMaster Carr for example:
http://www.mcmaster.com/#swivel-feet/=f6cser

 

[jwhendy]

@Q: Fantastic. We have those on some equipment at work; I'd not considered they would come in such small sizes.

 

[Mech_Engineer]

How about a flexure clamp where a screw clamp two jaws together, providing even clamping around the insert? We often use this sort of thing for cylindrical motor mounts and the like.

 

[jwhendy]

@Mech_Engineer: I need the square tube outer profile to remain unchanged because something rides up and down on it with rollers. What you describe sounds like I'd need to clamp from outside the tubing?

 

[Mech_Engineer]

You're right it would clamp outside the tubing. It was just a thought, but it sounds like you've got things in hand.

 

[jwhendy]

@Mech_Engineer: no problem! I appreciate the input. Many minds make light work :) Just found this forum and hope to stick around. I just googled "mechanical engineering forum" and was happy to find something for the question. Neat place.