Exacto knife straight cutter

This tool holds an Exacto knife and allows you to make perfectly straight and perpendicular cuts.  Especially useful for cutting foamboard.

Requires 2 M3x30 bolts, 2 M3 nuts and one M4x40 bolt for assembly.

Optionally one can insert a spring from a ballpoint pen (Diameter 4mm x 26mm).  In that case a short strand of filament can be used to secure the spring stopper in place.