Inspired by the New Fun Chastity Cage Hinge Pin but built completely from scratch. The design is based on an unbranded cage purchased from Amazon. Use a standard handcuff key to rotate/lock it once in place.
The dimensions (diameter x length) for the individual segments of the pin are as follows:
The tolerances used for the handcuff key way are extremely tight to preserve as much material (and strength) around it. My Smith & Wesson key is an exact fit; it slides in with minimal resistance and lightly holds onto the pin. You may need to adjust the tolerances around your key and/or printer.
Print vertically to ensure the key way and peg print as accurately as possible. This will require a support for the locking tab, but this segment is easiest to clean up post-printing.
I've had no strength issues even with regular PLA. The key way likely won't tolerate much poking around though so I advise against trying to unlock it without the key. ;-)
The "Horizontal Scaling Factor Shrinkage Compensation" value in Cura had to be adjusted to 105% for the model to print out (according to my digital caliper) at the exact dimensions specified.
The author marked this model as their own original creation. Imported from Thingiverse.