Movable blade unit for wood cutting machine

A blade unit for wood cutting machine, comprising:

• an axle being a rotating shaft;
• multiple first blades connected to at least one first positioning collar which is mounted to the rotating shaft, the rotating shaft including multiple grooves defined axially therein;
• a movable blade unit mounted to the rotating shaft and including a second blade and an inner ring which is located between the second blade and the rotating shaft, and
• a movable ring connected to the movable blade unit and having a flange, an outer collar and the inner ring, the flange connected to the outer collar which is rotatably connected to the inner ring, the inner ring mounted to the rotating shaft and a gap defined between the inner ring and the rotating shaft, multiple sets of rotating members connected to an inner periphery of the inner ring and being in contact with the grooves in the rotating shaft.