DOM ix core retention nut

In the photos you can see the press-fit pin in the top left hole of a DOM ix lock (when viewing from the lock face), which when pressed in prevents the core from turning more than 90° and only allows it to turn in one direction, as well as preventing it from being removed for gutting. 

After pressing out the pin, the core can turn freely in either direction when the pins are lined up, and removed for gutting, but this lock had no additional retaining clip, so I made this square nut in PLA with 10% infill, large enough for finger tightening on the back of the core for retention.