Straight keys, with a square or rectangular cross section, are the most common type of key. Install them in keyways to transmit torque from shafts to gears and other components.

Thread a screw through the tapped hole to pop these keys out of a keyway. When installed, they fill oval keyways completely, reducing stress on the key and shaft. The rounded ends make it easy to slide gears, hubs, and other components into place.

Slightly larger than the size listed, these oversized keys offer a tight fit in worn keyways.