A blade housing assembly for a power operated rotary knife including a split blade housing and a cam mechanism actuatable for changing a blade housing diameter between a blade supporting position and a blade changing position. The blade housing including an annular blade support section, a mounting section and a radially extending split extending through the mounting section and an inner wall of the blade support section and defining a split distance between first and second circumferential ends of the inner wall. The mounting section includes a first body portion and a second body portion on opposite sides of the radially extending split. The cam mechanism includes a cam plate bridging the first and second body portions and a cam member rotatably supported by the cam plate. The cam member is rotatable between a first, closed position and a second, open position to change the blade housing diameter.
