Rear lens cap for Berning Robot Royal cameras (M31 breech-lock mount)

thingiverse

I'm searching everywhere for rear lens caps for my Robot Royal lenses but they seem impossible to find, so I've decided to design one myself. I drew inspiration from a vintage Voigtländer rear lens cap made of leather and felt to create this simple replacement lens cap. Once the part is printed, you'll need to glue a piece of felt inside the cap (see image). In my case, I used cheap self-adhesive 2mm felt from a hardware store that I cut into a strip measuring 7mm by +/-108mm. Keep in mind that if you use a different thickness of felt, your lens might not fit properly (in this case, just redesign the lens cap with an appropriate cylinder thickness).