cam 118 should be in the unclamped position and clamp washer 124 is loosely retained between the cam 118 and head flange 113 to clamp the saw blade 60 the operator presses down on cam lever 120 the movement of cam lever 120 causes cam 118 to rotate into the clamped position and moves portion 121 of peripheral surface 119 into contact against the outer face 126 of the clamp washer 124 as cam 118 rotates it exerts an increasing force onto clamp washer 124 which in turn exerts increasing force onto blade 60 when cam lever 120 is substantially parallel to the plane of blade 60 cam 118 will be positioned so that first portion 121 with diameter d 1 is exerting the maximum compressive force on blade 60 simultaneously as cam lever 120 moves down it drives down first end portion 132 of cam release lever 130 and second end portion 134 up to unlock blade 60 the operator may press down on end portion 134 of cam release lever 130 the cam release lever 130 will pivot around pivot pin 116 and first end portion 132 will move up thus pushing up against the underside of cam lever 120 as cam lever 120 rotates upward it will rotate the cam 118 peripheral surface 119 will rotate from first portion 121 to second portion 122 in contact with surface 126 of clamp washer 124 thus releasing the force exerted against the clamp washer to complete removal of the saw blade 60 the operator unthreads the head 114 from the shaft extension 112 with his fingers while the above description constitutes three preferred embodiments of the invention it will be appreciated that the invention is susceptible to modification variation and.