Key and Keyway Calculator

• •Use the Key and Keyway Calculator when solving homework or exam problems that require quick numerical verification of your hand calculations — instant feedback helps identify arithmetic errors before they propagate.
• •Use it during the early design phase to rapidly iterate on parameters and narrow down feasible configurations before committing time to detailed finite element simulations or full design packages.
• •Use it when reviewing a colleague's calculation or checking a vendor's data sheet for plausibility — a quick sanity check can prevent costly downstream errors.
• •Use it to generate reference data for a technical report or presentation without manual computation, ensuring consistent, reproducible numbers throughout the document.
• •Use it in the field when a quick estimate is needed and a full engineering software package is not available.

The Key and Keyway Calculator is a precision engineering calculation tool designed for students, engineers, and technical professionals. Calculate shear and compressive stress in shaft keys and look up standard ANSI key sizes by shaft diameter All calculations are performed using established engineering formulas from the relevant scientific literature and standards. Inputs support both metric (SI) and imperial unit systems, with unit conversion handled automatically — simply select your preferred unit from the dropdown next to each field. Results are computed instantly in the browser without sending data to a server, ensuring both speed and privacy. This calculator is intended as a supplementary tool for learning and design exploration; always verify results against authoritative references for safety-critical applications.

Shaft keys transmit torque between a shaft and a hub (gear, pulley, sprocket). Standard key dimensions follow ANSI B17.1: for shaft diameter d, the square or rectangular key has width w ≈ d/4 and length determined by torque requirements. The key sees both shear and compression (bearing) stress. Shear stress τ = F/(w·L) = T/(r·w·L), where F is the tangential force at the shaft surface, r is shaft radius, w is key width, and L is key length. Compression (bearing) stress σ = F/((h/2)·L), where h is key height. Design checks both stresses against allowable values. For rectangular keys, the height h typically equals the width w (square key) or is slightly smaller. The typical failure mode is shear on the plane through the middle of the key; bearing failure on the keyway walls is less common. Keyway stress concentration reduces shaft strength by 15-25%, which is why reported shaft yields include this factor. Woodruff keys (semicircular) and tapered keys are alternatives for specific applications. Splines (multiple parallel keys cut into the shaft) handle higher torques than single keys with less stress concentration.

• •Gear-to-shaft connections in gearboxes, transmissions, and machine drives.
• •Pulley and sprocket attachment to shafts in belt and chain drives.
• •Coupling-to-shaft connections for motor shaft and machinery shafts.
• •Impeller-to-shaft in pumps and compressors.
• •Flywheel attachment in engines and punch presses.