XYZ Calibration Cube - 4mm OD tube cutting jig

I keep printing these XYZ cubes for calibration tests after changes and they don't do much. I figured that I might as well make a bowden tube cutting jig.

As everyone knows (by now), where the tube is inserted to the hotend or the nozzle, it must be perfectly right angle (90 degrees) or you can create potential filament jams.

To use this, insert the tube in the hole past the cutting point and slide a thin penknife in the slot from the Z face and cut it quickly. The cut area should