A 3-leg spider bracket to hold a 5mm (T1-3/4 pkg.) LED inside a 2-inch (52 mm) ID pipe. I wanted to hold the LED accurately in the center and this bracket does that. I used 2-inch plastic conduit (Schedule 40 PVC pipe) which Home Depot sells in 10-foot lengths.
The parametric OpenSCAD file allows choice of any ID, OD, and thickness if you have some other diameter pipe or smaller/bigger center items.
When printed from MakerWare 18.104.22.168 on Replicator Dual with standard profile, each of the 3 arms (intended to be solid) actually have a thin center gap, which you may see in the photo. Anyway it works as intended.
I just printed on the Makerbot Replicator Dual (110 C build platform) with the standard resolution, without using a raft. It came out quite nicely. Pretty simple design so will likely print without much trouble.