[MrFlippant]

Note: depending on printer/print setting then the hole/slot may need some fettling either on the print settings or with a drill/file for best fit.

My printer is well dialed in, but the lock ring is so loose it just falls off. I assume you added a gap of some kind in the model? I can import the STL and mess around to remodel it, but figured I'd ask if you'd be willing to share the files as STEP for easier editing, or post a version of the ring with zero gap. When I print models with a zero gap, it's usually a good, snug, press on fitment as the design would dictate.

EDIT: Never mind. I remembered a new feature in the latest PrusaSlicer, and was able to easily scale the ring to the correct size for zero gap. I'll print it now to see how well that worked. :) I also found that the original model size is way too big for the slot.it kex keys I have, but it fits the ScaleAuto/RevoSlot size keys perfectly. I'm going to scale it down for the slot.it version and see how well that works.