Keyways Spec Table
2 types of spec data
Keyways are the grooves machined into shafts and hubs to receive a key for torque transmission. KS B 1311 specifies shaft and hub keyway depths for each key nominal size. Fit combinations — key-to-shaft N9/P9, key-to-hub Js9/D10 — are selected based on load characteristics; interference fit (P9) is recommended for shock loads.
Frequently Asked Questions
What are the machining methods for keyways?
Shaft keyways are machined by milling or slotting (shaping); hub keyways are typically broached. End-mill machining creates a rounded keyway end; slotting creates a square end.
What is the difference between keyway fit tolerances N9, Js9, and P9?
N9 (normal) for general power transmission; Js9 (sliding) for easy key insertion and removal; P9 (interference) for heavy shock loads. Both shaft and hub keyway tolerances must be considered together.