A rotary tattoo machine includes an inner housing; a tattoo needle; an electric motor including a shaft assembly; and a bearing arm including a bearing. The machine also includes a cam, the cam moving up and down the shaft assembly due to the rotation of the shaft assembly and the bearing, the moving of the cam to drive the tattoo needle from a retracted position to an extended position. The device my also include an outer housing or grip. The dimensions of or a shape of the cam reduces an amount of dwell time of the tattoo needle. The cam may be replaced by an alternate cam, the alternate cam having different dimensions or a different shape from the dimensions of or the shape of the original cam and the alternate cam to have a different amount of dwell time associated with the tattoo needle.