An eccentric gear for a tattoo machine allows the throw of the needle of the machine to be quickly and easily changed without the need to adjust the springs of the machine. The eccentric gear, which is rotatably connected to the output shaft of the motor and also to the linkage bar, has a body member that has a channel on its upper surface. A slide plate, to which the linkage bar is rotatably connected, is slidably disposed within the channel so that movement of the linkage bar-slide plate connection point closer to or farther away from the longitudinal axis of the output shaft, decreases or increases the throw of the needle respectively. A set screw frictionally locks the slide plate within the channel.