OpenBeamMiter cut straight edges on OpenBeam v2.1

A Miter-Box to cut 90 degree ends straight on OpenBeam v2.1 or other 15mm x 15mm aluminum extrusions.
Place part into the box with your desired cut mark centered against the split in the center of the miter-box. Use a Hack saw or coping saw in the miter box's saw groove and use plastic on both sides to guide your cut.
Also useful for marking straight line on extrusion. Slide over OpenBeam and use the outer edges to mark sides of the aluminum!
Print 2 to support the other end of long extrusions.