The invention relates to a method and tools for producing a braking band (2) of a disk-brake disk (1) by casting, in which the disk comprises at least two plates (3, 3') connected to one another by connecting elements (4) forming an internal air-duct (7) for the cooling of the braking band (2). With the method and the tools, a disk is produced in which at least one of the plates (3, 3') has, in its surface (8, 8') defining the air-ducts (7), at least one groove (10, 10') having a cross-section which becomes wider towards the air-duct.