Designed to fit a 28.5mm dowel with 3 screws to attach it to the dowel. I added a hole from the top of the thread so you can screw through the thread into the end of the dowel giving it extra strength. May or may not be needed.

 Recommend not using PLA due to it's brittle nature but by all means give it a go, with the end screw, it might give it the extra strength it will need.

Designed not to need supports through the body however it is up to you if you want to use painted on supports in PrusaSlicer for the treads. I tried both , supports was definitely a more snug fit but the one without supports still screwed in fine and didn't wobble. 

100% recommended for strength. Print in draft mode (.30)

Print instructions

Printer Brand: Prusa
Printer: i3 MK3s
Brim: Yes
Supports: No
Resolution: 0.30mm
Infill: 100%
Filament: Polymaker Orange PETG