3D-Printed Flat-Frame Fabric Hoop for a 6″ Newtonian
After a successful imaging night, I needed to shoot new flat frames for my updated optical train. While breaking yet another rubber band attempting to stretch the t-shirt across the front of my scope, I knew there had to be an easier way to do this. Now, I know this isn’t really a problem, it’s just a minor inconvenience and, honestly, an excuse to design and print something new, which is always fun.
I spent a day in Fusion 360 designing and printing iterations: an inner ring that fits around my dew shield, a split outer ring with a screw tensioner, and a t-shirt stretched between them. After testing v1 and refining the design, v2 is tighter, more reliable, and ready to share.
I cut out some pieces of white t-shirt large enough to cover the whole hoop and clamped it between the inner and outer rings. Crank the screw at the top and the outer ring compresses inward, stretching the fabric flat across the aperture. I added a ring you can screw onto the back to keep the inner ring from popping out backwards. It’s not strictly necessary, but it completes the assembly and cleans up the look. The inner ring is sized to fit loosely around my six-inch Newtonian dew shield.
When I finished and showed it to my wife, she took one look and, in her typical unimpressed tone, said, “Oh, that’s just an embroidery hoop.” And she was right. Well, that’s what I get for not doing my research. But regardless, at least this will be the right size for my telescope.
Want to print one?
If you’re interested in printing one out, you can find it on Thingiverse or MakerWorld — links below — or download it right here from my website.
This is sized specifically for the 6-inch Newtonian dew shield I 3D printed, with an innermost diameter of 193mm. As long as your scope is smaller than 193mm it should work — so this should fit any 6-inch Newtonian, with a little extra space to hang down over the front. If you need a different size, you should be able to scale it to fit.
The two bolts that lock the outer ring down and provide the clamping pressure are M5s. If you decide to add the back ring — the one that keeps the inner ring from popping out backwards — those are M3 screws.
I printed this in PLA with very standard print settings. PLA is fine here because I don’t intend to leave this out in the sun; I’ve been doing my flat frames inside. If you wanted to leave it out on the scope, you could easily print it in something tougher like ABS or ASA instead.
