Keystock are removable bars that are used to transmit torque from components including couplings, sheaves, sprockets and gears to a shaft. They are called “keys” because they lock a component to the shaft by means of a corresponding keyway in a shaft. Keystock is available in both inch and metric sizes. Common keystock materials include steel, stainless steel and plated with zinc and are supplied in standard lengths of 12” long. Keystock can be rounded at both ends, squared at both ends, or rounded at one end and squared at the other.

There are many different types of keystock available including machine keys, Woodruff keys, hi-pro keys, gib head keys, and hex keys. Machined keystock is available in standard sizes and ready to use without additional cutting or filing. Woodruff keys are semi-circular components (half moon) installed deep in a shaft and firmly embedded. Hi-pro keys are similar to Woodruff keys, but lock into place. They provide superior strength and vibration resistance. Gib head keys are notched and tapered to tightly couple gears or pulleys with a shaft. Hex keys are L-shaped bars with a hexagonal head. They are used to turn screws with hexagonal sockets. The following chart details standardized keyways and setscrews utilized for inch sized shafts: