A blade sharpening system for log saw machines is provided. An example multiphase grinding wheel has a grinding face with one or more abrasive concentric rings for sharpening the cutting blade of the log saw machine, and one or more padded concentric rings consisting of fiber padding. Sharpening with the multiphase grinding wheel improves cut quality, increases blade life, removes glues and varnishes from the cutting blade, reduces blade deformation, and hones the edge of the cutting blade. A pneumatic tensioning system uses air bladders to apply a dynamically cushioned pressure between the grinding wheels and the cutting blade. The fiber-padded grinding wheels and the air bladder tensioner provide improved sharpness of the cutting blade and longer life for the mechanical components. The padded grinding wheels decrease fire risk, and the tensioner can be operated remotely, decreasing human injuries common with conventional setup actions near the sharp cutting blade.