Abstract: A holder for a machine tool includes a cone-shaped base body. One end of the base body has a larger diameter than the other end and includes an annular flange extending therearound. The flange includes first and second recesses formed therein. Each recess includes a bottom surface. The first and second recesses respectively form identical first distances from the bottom surface to an outer periphery of the flange. One of the recesses includes a hole. A depth-reducing element is securable in the hole such that an outer surface of the element is disposed between the bottom surface and the outer periphery, wherein an effective depth of the recess having the depth-reducing element is shorter than an effective depth of the other recess.