Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:5185105.

Needed a key for my water ejector on the outside of the house.

The key is for a 7.8mm lock and to allow for margins in the print I made the hole 8mm.

Make sure to use enough infill, you don't want the key breaking inside the lock, I used curas default 20% and it has been working great for a couple of years but just to be extra safe I would use a bit higher.

Hope it can help somebody else.