Horizontal rotary mower with thin replaceable blades

A lawn mowing apparatus for cutting grass growing on a surface, comprising:

• a drive mechanism;
• a rotatable blade assembly connected to the drive mechanism comprising two or more rotors configured to rotate about an axis substantially parallel to a surface to be cut, each rotor comprising a plurality of blade holding elements defining a blade channel no more than 0.075 inches thick configured to hold a replaceable blade;
• a blade assembly guard configured to partially enclose the rotatable blade assembly;
• and
• a plurality of replaceable blades, each no more than 0.075 inches thick, each of the plurality of blades comprising:
• a ductile portion having a hardness less than Rockwell C 50;
• and
• a hardened cutting edge having hardness of at least Rockwell C 50,
• wherein:
• each of the plurality of blades is held in one of the plurality of blade holding elements in each of the two or more rotors;
• the rotatable blade assembly is rotatably driven by said drive mechanism about the axis such that each of the plurality of replaceable blades is held substantially tangentially to each of the two or more rotors such that a cutting edge of each of the plurality of replaceable blades is oriented in a direction of rotation of the two or more rotors to cut grass without a stationary bedknife;
• and
• the blade assembly guard defines a blade chamber.