OpenSCAD threads module" by dan_kirshner for his threads program which made this design possible.
This is a model of a shaft to fit an iOptron Cube Pro (possibly others). This is only a model to check the fit and thread specifications prior to machining. The printed version of this in any material will not be strong enough to be used in the mount. Please do not mount a telescope on a printed shaft - it will break! When the clutch is tightened the shaft is under tremendous tension and needs to be turned from stainless steel.
This shaft is designed to take the iOptron Secondary Saddle #8953. The #8253 saddle has the same thread as the end cap (but does not include canting adjustment screws - needed to put the target in the center of both telescopes).
I turned 4 of these in 303 stainless steel for ease in machining. They appear to work well.
Put both files in the same directory (threads.scad and iOptron Shaft.scad). This takes a long time to render. No your computer did not freeze up. Go get a cup of coffee and breakfast kind of time.
It is about a 6 hour print @.1 mm / layer for a finish good enough for the threads to work with the real parts.
Flip the model on the table and use support from the table only. A brim (not a raft) is a good idea.
I used PLA-CF carbon fiber material - provides a great finish.