2D Level Fixture

Today I needed to drill eight holes in the ceiling, so I decided to buy a 2D bubble level indicator and print a mounting for it to ensure that the holes are perfectly upwards directed. The mounting is fixed by an M3 button head screw, the bubble leveller by 10mm Spax type self drilling screws (id=3mm). It took me two trys to come to these dimensions. Soon I will also post a design for a capsule bubble level (Dosenlibelle in german, hope I translated it right). The inner diameter is designed for