The utility model relates to an assembly comprising a dial (1) and a base plate (2). The base plate is limited by an upper peripheral edge (4). The upper peripheral edge extends downwards through a peripheral surface (6). The dial is fixed on the upper peripheral edge of the base plate through at least a first fixing device and a second fixing device. The assembly is characterized in that the first fixing device comprises projecting parts (18) arranged on the peripheral surface of the base plate; the dial has peripheral borders (10); the dial is retained between the heads (14, 24) of nails or screws (12, 22) and the upper peripheral edge of the base plate through the peripheral borders; and the heads of the nails or screws extend through rod parts (16, 26) accommodated in the projecting parts (18) of the base plate.