A diamond wire cutting machine includes a spool on which a diamond wire is wound. The spool includes two end flanges having respective frustoconical faces adapted, by cooperation of shape with frustoconical faces of two adapters, to center the spool on an axis of revolution. A drum extends from one of the end flanges to another of the end flanges. The drum includes a cylindrical outer face of circular cross-section on which the diamond wire is wound. The drum defines a central hole through which a drive shaft passes. The drum and the end flanges form a single plastic block.