Belt Drive API
Belt-drive and pulley maths as an API, computed locally and deterministically. The belt endpoint computes the length of an open V-belt or flat belt from the two pulley diameters and the centre distance with L = 2C + (π/2)(D1+D2) + (D1−D2)²/(4C), and returns the belt length plus the wrap (contact) angle on each pulley; pass a driver rpm and it also gives the belt surface speed. The ratio endpoint computes the speed ratio of a pulley pair (driven ÷ driver diameter, since N1·D1 = N2·D2): give a driver or driven rpm and it returns the other, the torque ratio and the belt speed. The centers endpoint reverses the length equation to find the centre distance for a target belt length, solving the equation numerically. Diameters and distances accept millimetres, centimetres, metres, inches or feet, and lengths are reported in several units. Everything is computed locally and deterministically, so it is instant and private. Ideal for machine and drivetrain design tools, maintenance and MRO apps, maker and CNC projects, and mechanical-engineering calculators. Pure local computation — no key, no third-party service, instant. Live, nothing stored. 3 endpoints. This is belt-and-pulley power transmission; for bicycle gear ratios and development use a bike-gear API and for bolt tightening torque use a torque API.
api.oanor.com/beltdrive-api
