This design is inspired by https://www.thingiverse.com/thing:2437743.

There are several GoPro cap mounts for ordinary 500/330ml bottles but 100ml is more than enough. I found a 100ml bottle (nail polish remover) in the store. The thread outside diameter was 23.6mm.

I also wanted a strong connection to the camera.

I used ANSI Unified Screw Thread 1” 1-8 UNC class 3B in Fusion 360. It’s not a perfect fit but it works. It is not a water tight seal but the weight of the camera will hold the cap down so the air can’t escape anyway.

I warped some bitumen tape for good grip and some yellow tape for visibility.

Fusion 360 files included.

Requirement:
One stainless M5 nut.

Creality

Ender 2

No

No

0.2

20

I used 4 bottom and 4 top layers for waterproofing