Press Fit API
Interference (press and shrink) fit engineering maths as an API, computed locally and deterministically from the Lamé thick-wall equations — the contact-pressure, holding-capacity and assembly-temperature numbers a mechanical designer or machinist sizes a shaft-and-hub joint with. The pressure endpoint gives the contact pressure that builds at the interface from the diametral interference, the shaft and hub diameters and the elastic modulus, plus the tensile hoop stress at the hub bore — the highest stress in the joint, which a thin hub can split if it exceeds the yield: a 50 mm solid steel shaft in a 100 mm hub with 0.05 mm interference makes about 75 MPa of contact pressure and 125 MPa of bore hoop stress, and doubling the interference doubles the pressure. The holding endpoint turns that pressure into the axial push-out force and the transmissible torque through the friction at the interface (force = pressure × contact area × friction, torque = force × shaft radius), the figures that decide whether the joint slips under load. The assembly-temperature endpoint gives the heating (hub) or cooling (shaft) temperature change for a shrink fit — ΔT = (interference + clearance) ÷ (α × diameter) — so the part slides on freely and grips as it returns to temperature. Everything is computed locally and deterministically, so it is instant and private. Ideal for mechanical-design and machine-building tools, manufacturing and CAD utilities, and engineering calculators. Pure local computation — no key, no third-party service, instant. Same-material Lamé estimates — verify against the material yield with a safety factor. 3 compute endpoints. For thin-wall pressure-vessel stress use a pressure-vessel API.
api.oanor.com/pressfit-api
