A customisable cryptex which can be programmed to any password you want which uses letters and numbers! Instructions are in the instructions.txt file. I left pretty decent tolerances on the parts, so they should go together fine, but the "click" which would ideally keep the rings aligned may be a bit anemic or mushy depending on your luck. This is something I'm working to improve.
This cryptex has 8 rings, each with 36 characters.
This equates to over 2.8211099 x10^12 combinations, or over 2,821,099,000,000, or over 2.8 trillion (thousand billion, or million million) combinations.
Trying one combination a second, it would take over 89,395 years to try every combination, so this thing is stupidly secure (unless you just crack it open).
The letter parts are best done at a fairly high resolution (~0.1mm layers) to get the characters nice and clear, but the rest can be done at a lower resolution (0.2mm+ layers)
The finished thing looks better in person: black PLA is a pain to photograph.
Fair warning, this needs a lot of parts, and will take a while to print, but the result is pretty awesome.
I actually designed this a couple of years ago, I can't believe I never uplaoded it before now. I hope you like it!