This lock has a spring loaded wafer that locks the cylinder core in position until the key is inserted.  The tailpiece slips onto the inside end of the core and can be held in place with a screw.  The pilot hole is designed for a #8-32 machine screw (needs to be tapped before screwing in the screw), but an M4 screw would also work.  The tailpiece is a tight fit, so a screw is not necessarily needed.

The lock fits a standard cam lock opening, and the nut will hold it in place.  Careful not to tighten too much!  The lock cylinder will snap (I discovered the hard way…)  Use a 7/8" wrench or socket on the nut.

The print is set up for PLA, with solid infill, 0.2mm quality.  Hollow is not strong enough.

Any feedback is welcome!