Tube miter templates, free and exact

The Monsoon Miter tool generates printable, cut-ready coping templates for any tube pairing in your browser, with wall-thickness compensation and compound seat stay joints.

Monsoon Cycles, Colorado Springs · Updated August 16, 2026

Every steel frame is a set of tubes fish-mouthed into each other, and every builder needs paper templates to mark the cuts. The old TubeNotcher program served a generation; ours carries that torch with a modern engine, verified against it to fourteen decimal places.

What it handles

• Any cut tube into any base tube diameter, including head tubes, BB shells, and seat tubes
• Offset joints and the compound seat-stay-to-seat-tube reduction, the joint that defeats most generators
• Wall thickness compensation: the solid line is your cut, the dashed line is the theoretical centerline
• Print at exact scale with an on-page calibration ruler, or export the whole frame's seven templates as one PDF from a Frame Lab design

The math is a parametric cylinder-intersection sweep, and the verification suite is public in spirit: the engine matched an independent numeric root-finder to millionths of a millimeter before we shipped it.

Questions riders actually ask

Are the templates dimensionally exact when printed?

Yes, if you print at 100 percent scale. Every sheet includes a calibration ruler; measure it before you cut.

Can it do seat stays?

Yes, including the compound side-view-plus-spread reduction with centerline offsets for left and right stays, which is the joint most free tools skip.