A series of drill bit stop collars to prevent drilling deeper than absolutely necessary. In the generally most used EU sizes.
Each collar should print in about 20 minutes.
If you want other sizes added, tell me in a comment and I can add those at a later point.
The screw used to tighten each piece is a 3x10mm column head with inner hex. (head diameter 5,5mm.) It should self-tap into the collar on first use.
There is a 0,05mm oversize in the holes for the drill bits and should slip over them with relative ease. For me they did at least. Otherwise you can drill them to size using the drill bits they are meant for.
The author marked this model as their own original creation.