by selmo, published
These are pipe clamps, commonly used for scaffolding, trusses and lighting rigs. In pairs, they hold two pipes together with a pivot. Used singly they can be used to clamp other things to a pipe (lights, etc).
These are sized for 1/2" steel pipe and 1/4"-20 bolts. A 1/4"-20 carriage bolt and wing nut tighen the clamp around the pipe, and a short 1/4"-20 bolt / nut is used to fasten them together / to other things. I use them to fashion quick temporary jigs and frames from pipes.
The pivot is not a bearing. It's just some flexibility when setting up the position and not meant to be spun around. The nut and bolt will unscrew and it will come apart!
There are so many variables when printing that their strength cannot be guaranteed. Therefore, consider these LIGHT DUTY -- and not replacements for steel clamps. They are not strong enough to trust anyone's life to! Don't use these to clamp a 200 lb spotlght over someone's head! Use at your own risk.
Stick a 1/4"-20 bolt through the hole in the end. Make sure the head of the bolt does not intrude into the pipe's area. Stick a matching nut in a second clamp and put them together (add a washer or two as needed to smooth pivoting and adjust length)
Sitck a 1/4"-20 carriage bolt through the clamp, into the side with the square hole. Put a wingnut on the other end. Slide over the end of a 1/2" steel pipe and tighen wingnut to clamp.