You are not a loser if you cant loosen a nut. But you could use one :)

Simple tool for tightening or loosening nuts and bolts that can replace 6 most common wrenches.

Cube includes following sizes:

6mm

8mm

10mm

12mm

13mm

15mm

Recommended print settings:

Layer height: 0.12-0.16mm

Perimeters: 5+

Infill: 30%+

Infill pattern: cubic

If you are not sure about tolerances print the 10mm tolerances test piece first and then adjust x/y hole compensation if necessary.