I wanted to remove the compression fitting in my imaging train for a while. It was surprisingly difficult getting an all-threaded setup with my Explore Scientific ED102 due to the male M54 x 0.75 threads on the focuser draw-tube and same male M54 threads on the Stellarvue SFFR102-2 field flattener & reducer.
To get around this, HighPointScientific suggested a thread inverter, but it is not available for sale yet. In the mean-time I created a 3D printed a M54x0.75 coupler to connect the draw-tube to the flattener & reducer. https://www.thingiverse.com/thing:4238561
I’ll stick with this for now, but still am on the lookout for a metal M54 thread inverter due to a couple of flaws with this setup.
- The 3D printed design does allow some light to pass through — not enough to impact imaging.
- The plastic (PLA) threads cannot be overtightened due to high risk of stripping and slippage
- I’ve got my eye on this one when it becomes available