In ITALIAN, use google translator (sorry for that)

This is a helical focuser for the ZWO off-axis guider, to be used with an ASI120mini or with other mini cameras of similar size (diameter)
I don't know if it will also work on other off-axis guiders, but this project of mine is definitely designed to attach to the OAG body via the T2 male thread

This focuser consists of 3 parts:

• the yellow part is where the 120 mini is inserted: the 120 mini will be locked with at least one M4 grub screw/bolt (metric)
• the blue part inserts into the green one and remains in place once the 4 M5 grub screws (metric) are tightened: the part must be free to rotate and only after focusing can you consider tightening a grub screw/bolt further to lock it
• the green part is the base that screws onto the ZWO OAG

Everything is designed very precisely and can be printed in FDM, provided that the vertical resolution is at least 0.15 mm. PLA is perfectly fine, even better if higher
The operating principle is simple: you rotate the blue part and the yellow part moves up or down, moving the ASI120 mini closer to or further from the OAG body: the useful vertical focusing range is approximately 4 mm, so you fix the 120 mini in a reasonable starting position for fine focusing
In addition to printing, you will need:

• 4 M5x8 grub screws/bolts (for the green part)
• at least 1 M4x6 grub screw/bolt (to lock the ASI120 mini)

I recommend:

• putting silicone grease in the T2 thread and in the internal thread that moves the yellow part up/down
• before inserting the grub screws/bolts into the various external M5 and M4 threads, I recommend re-tapping the threads: if you don't have taps, simply heat a bolt with a lighter (without overdoing it) then screw it in so that it carves the "correct" path in the plastic: if you print with an SLS or similar, you will obviously have no problems

I recommend positioning the parts on the print bed as shown in the attached image

vIDEO: https://www.youtube.com/watch?v=fC01ipZAYhM

Zortrax