Is there something so exiting as when you can test something new that you have built ?
I could do my first indoor test of the focus motor with it's 3D printed parts today. It's the USB-Focus and I control it through APT and ASCOM driver. Have a look at page 7:
http://www.astrofriend.eu/astronomy/...0mm-setup.html
The gear ratio I could achive let me use 30'000 steps of the 65500 availably. There is also an instruction how I calibrate the focuser.
/Lars