Extension tubes for c-mount lenses customizer

An openSCAD script generates extension tubes for c-mount lenses. Made with the tolerances required for a low-resolution (0.3 mm) printer. Lenses should thread in tube without printed threads.

UPDATE: Tweaked the measurements to fit snugly on lens and in c-mount without forcing. Comment if you find different results with your printer and I can add a slider for adjusting the tolerances