Back in February I got a set of bike lights and the rear light mounted on the seat post perfectly, but I recently added a bike rack and bag which blocked the light from view. At first I attached the rear light (which is also a reflector) to the back of the bag, but it wasn’t ideal.
So looking at the options I thought mounting it to the back of the seat made sense, but I needed an adapter, so I designed and printed one. I’ve said it before, but I’ll say it again: This is why I like 3D printing. I’m not interested in printing little toys or trinkets, I am interested in solving problems.
I fired up OpenSCAD and designed a cylinder, split it in half, added holes/grooves to fit around the bars on the seat, and then added a hole for a bolt to go through to clamp it together.
One side of the bolt hole allows the head of the bolt to be recessed so it doesn’t stick out, and the other side allows for the hex nut to be held captive so you can tighten the screw with the nut held in place.
I remember back in 2012 when I asked Michael Curry if he got designs right the first time and the first print worked perfectly, and he said that most designs took about three attempts… I’m happy to say this one took just two! (Well, I could probably slightly improve things with a third attempt, but the second was close enough so I called it done.)
I did have to slightly cut down the bolt with a hacksaw to get it to not stick out too far. Again, a third print could have addressed that issue, but sometimes a hacksaw is the right solution to a problem.