A miter is the saddle-shaped cut that lets one round tube sit perfectly against another. Get the miters right and the frame practically holds itself for brazing; get them wrong and no clamp can save it.
Monsoon Cycles, Colorado Springs · Updated August 16, 2026
Every junction on a steel frame is one tube coped to another's curve. The template method wraps a printed pattern around the tube, marks the line, and lets a hand file finish what a hacksaw roughs out. The mathematics is a cylinder-cylinder intersection unrolled flat, plus the two corrections that matter: wall thickness (the cut line lives on the inner wall, not the centerline) and compound angles on seat stays, which meet the seat tube tilted in two planes at once.
Our free generator handles all of it in the browser, and one click from a Frame Lab design prints all seven of a frame's templates as a single PDF.