EleusisT's 3D printable DIY 1:10 crayford reducer / fine focus knob
My friend EleusisT has been working on and off for two years now on a 3D printable low-cost 1:10 crayford focuser reducer that’s available for free on Printables.com
They do not have a website (yet?) and mine seems to be good at SEO for super-niche stuff. So I’m putting this article about it so more people can have access to smooth, reduced focusers.
Market VS DIY
The problem with commercial 1:10 reducers is that they now cost north of 150€. On one side, the amateur telescope making community is really growing, with younger and younger people using 3D printers to build telescopes. Capable entry-level telescopes have never been so cheap to build, mainly thanks to 3D printing and mass production of optics in China.
This is a bit of an inversion of forces, because for a while, competing on price with commercial offerings was impossible for entry-level stuff. It’s only by polishing your own 16-inch or more mirror that you could beat the market, by sinking your own time. Projects like the Hadley telescope by Maff and community changed that. The Hadley is cheaper and better than commercial options at that price point.
The 1:10 reducer is another take on that matter. For about 1€ of material, you have a smooth focusing motion that does not fear comparison to 100€+ options. Of course, the nature of the mechanical design means there’s about 0.1mm of backlash, but this is irrelevant for visual use, the side of astronomy that is now accessible to many.
The Reducer project
For two years, EleusisT worked on the reducer and we (me and Raphaël who’s launching a 3D printing business) printed samples, gave feedback, and tried a few options. Today the project is mature and print-and-go solutions are starting to flourish :
- ST80 plug-and-play focuser reducer
- Crayford reducer V2 adapted for Bresser hexafoc focuser
- Crayford reducer adapted to Celestron SCTs
- Crayford reducer V2 adapted for Skywatcher “classic” focuser
- 1:10.2 focuser for Hypatia (Hadley telescope 1.25” crayford focuser)
I strongly encourage you to try it if you have a telescope in that list and a 3D printer. If you have another telescope, a 3D printer, and CAD skills, do not hesitate to design an adapter, and your project will join that list !