UPDATE 11/13/23: Changed the design of the lock to keep it from falling out or breaking. New lock (now in two pieces) can be printed separately, at 15% infill, and is compatible with cases you might have already printed!
Check out the instructions PDF for some crucial tips on assembling, and an Amazon link to the felt liner I used on the inside.
Shapr3D file I created it with is currently a bit of a mess, but I might clean it up and make it available for others to remix at a later date.