Abstract: A grinding disk (13) for manually held, motor-driven grinders (1) has a centrally arranged fastening recess (15) open at the grinding disk upper side with an internal thread arrangement (16), with which the grinding disk (13) can be screwed onto a connecting part (8), which is arranged on the side of the grinder and is driven for the grinding motion during operation, and which connecting part has a thread section (11) with an external thread arrangement (12), which is associated with the internal thread arrangement (16) of the grinding disk (13). The internal thread arrangement (16) is formed by a multiple thread with at least two thread courses, which are arranged angularly offset to one another. The diameter ratio between the diameter of the internal thread arrangement (16) and the outside diameter of the grinding disk (13) is at least approximately 0.25.