These are customized "Smooth n' Curvy" knobs designed for mounting my Celestron 8" GPS telescope to its tripod. They use 3" long 3/8" bolts, leaving 1" protruding from the knob. Depending on your printers dimensional accuracy, you may have to ream the hole out with a 3/8" drill bit so you can press the bolt in. Recommend flipping the model so knob side is down and printing with supports.
Printer:
Monoprice Maker Select
Rafts:
Doesn't Matter
Supports:
Yes
Resolution:
.2mm
Infill:
20%
Notes:
Recommend printing with at least 3 walls so you can ream if needed with a 3/8" drill bit.