Antenna mast wire pulley with anti-jam guides.  For 1" O.D.  US steel conduit and also for Max Gain Systems masts. by loughkb on Thingiverse: https://www.thingiverse.com/thing:7351831

Summary:
These are top mounts and pulley attachments for antenna projects.   I built in sloped guides to the edge of the pulley to keep wire or lines from slipping besides the pulley and jamming up.There are two versions of the top clamp.  One is for US 1 inch O.D. steel electrical conduit, the other fits the top of a Max Gain Systems mast.Print these with 6 perimeters and 50% infill for strength.   Also, rotate the U brackets and print them on their sides with the blades vertical for best results, print as is with supports for slightly stronger part if needed. But if you do, the support remnants may interfere with the pulley rotation.