Abstract: A grinding machine for releasable attachment to reel type mower units for the sharpening of the cutting components thereof. This grinding machine has a base which rests upon the ground with extensions therefrom for releasable attachment to the mower unit. A grinding head supported on the extreme end of arms is positionable in a sufficient number of directions such that a grinding wheel thereof may be brought into contact with the edge of the cutting elements whereupon the rotation of the grinding wheel brings about the sharpening of those cutting units. The grinding head components are mounted upon a carriage which is moved along the base in a direction parallel to the axle of the mower unit whereby the continuous length of each of the cutter elements may be sharpened. Further attachments are provided whereby the grinding machine may also be used to sharpen the bed knife of the mower unit.