Rack and Pinion Telescope Focuser 1.25-2"

cults3d

Had a cheap 10" dobsonian telescope that needed a new eye piece focuser, so decided to create a 1.25 to 2" rack and pinion design. I printed out the parts using ABS and had to use a lot of sanding to make it as snug as possible to prevent slippage. The gear, gear rack and rod were things I already had so I did not print those, but I am sure you probably could get away with doing that. I have been using this rack and pinion design on my telescope with good success, though have had issues with the plastic shrinking in the cold weather, making it hard to put in or remove the eye pieces. For the screws, I have m3 screws I used, and bought some brass inserts that I melted into the parts where the holes are. I also added a doubled up strip of aluminum from a soda can within the ridge along the length of the main tube for the screw to press against to hold it in place. For the gear box on the base, to make the print easier, I had the top of it printed separately so that the hole wouldn't need to be filled with infill. I had the curved part that meets the needs of a 10" dob curvature printed separately to eliminate the need of support under it, and just glued the curved base with the base tube using superglue. You can still print out the entire base in one part if you wish. The 1.25 inch adapter does not have a threaded end for filters. This is still a work in process and will keep you updated.