lf of the interior and half of the exterior. ??? ??? ??? Interference The act of hindering or obstructing or impeding. ??? ??? ??? Key A rectangular or semicircular shape used to prevent parts, such as gears or wheels, from turning on a shaft. ??? ??? ??? Keyseat A slot in a shaft to receive a key. ??? ??? ??? Keyway A slot in a hub or material around a shaft that receives a key. ??? ??? ??? Param