The cutting machine for cutting logs of web material, includes a cutting head arranged along the feeding path of the logs. The cutting head includes a coupling for a disc-shaped cutting blade and is designed to impart the disc-shaped cutting blade a rotary motion around the axis thereof and a cyclic movement to cut the logs into single rolls, and to allow the logs to move forward along the feeding path. The machine also includes a store unit for disc-shaped cutting blades associated with the cutting head. A handling member is provided to remove a worn disc-shaped cutting blade from the cutting head and replace the worn disc-shaped cutting blade with a new disc-shaped cutting blade taken from the store unit.

Apparatus for trimming paper rolls or logs (2) including: a section for the entry of the logs (2) to be trimmed; a section for the exit of the trimmed logs (2); a station with cutting device (6) for trimming the logs (2); a device (3) for moving the logs (2, 2) between the entry section, the cutting station and the exit section; a device (4), associated with the log-moving device (3), for retaining the logs when subjected to movement.

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.

A cutting machine includes a circular knife and a grinding unit for grinding the circular knife, wherein the grinding unit can be adjusted to grind the circular knife at different angles.