This is a rotator lock, for light use. It is really just a unnecessarily complicated slide bolt, activated by a rotator - but it looks pretty!. The rotator has a 60-degree twist, so well within the human wrists' single movement limits and the bolt extends 20mm on that movement. Securing bolts (6) are M3 (12mm for the example), nuts are Nyloc, backplate acts as the washer and sandwich any material that requires re-enforcement e.g. Corotherm Sheet.  

For a nice finish, print the lock cover with the outside facing up & with support touching bed ‘on’. It is a little work to remove waste from the cavity, but wholly possible. Alternatively, print upside down for easier support removal but a lesser finish. The clasp prints right way up. The bed support for the clasp removes very easily.  The rotator actuator arm also requires bed support - which removes very easily.

Made from PETG. As used in the Budget Printer (Corotherm) Enclosure Project [ here < Printer Enclosure by Rosti | Download free STL model | Printables.com > ]