Foldable Angle Finder

The rulers, the thumbscrew and the glider have been redesigned. 
The gauges fit concave angles now.

Assembly:
Two M3 nuts and a M3x16mm socket head cap screw are needed. 

PETG is recommended for the fastener's torque forces. 
No supports needed. The thumbscrew is pre-supported (bridge).
100% infill or full wall thickness will also help prevent hold the nuts firmly in place.