Keys Spec Table
Keys are fastening elements inserted between a shaft and a hub (gear, pulley, coupling) to transmit rotational torque. Parallel keys (KS B 1311) are most common; Woodruff keys are widely used on small-diameter machine tool shafts. Keys are typically S45C material; for heavy loads, the shear strength and compressive stress on the key sides must be checked.
Frequently Asked Questions
What is the difference between a parallel key and a Woodruff key?
Parallel keys have a rectangular cross-section with keyways in both shaft and hub, suited for high torque. Woodruff keys are semicircular with a deep shaft-only groove and self-aligning feature, mainly used on tapered shafts.
How do I select key dimensions?
Key width (b) × height (h) is determined by shaft diameter per KS/ISO standards. Example: 20–22mm shaft → 6×6, 30–38mm shaft → 10×8. Key length should be 1.0–1.5× the hub length.