The invention relates to a mounting device for a drum (2) consisting of at least two joined drum segments (21, 22) as a part of a shaft (1) of a brush roller, said mounting device including an internal circumferentially directed shoulder (24) being a part of a first drum segment (21) and an external circumferentially directed shoulder (23) being a part of a second drum segment (22), said two shoulders (23, 24) are provided with cooperating contact surfaces mainly positioned in a circumferential or tangential direction with respect to a complete drum (2), the external shoulder (23) being provided with a radial directed clearance hole intended to involve a screw (30), the threaded end of which being directed into the geometrical rotation axis of a complete drum, whereby the interior circumferentially directed shoulder (24) is provided with a recess (26) having a bottom (25) and an opening (27) facing the geometrical rotation axis and the recess (26) is designed with plain inner side surfaces (42, 43) facing each other and being parallel and axial with respect to the drum, and the recess (26) is equipped with projections (28) tangentially and circumferentially originating from each one of said side surfaces and pointing to each other. Furthermore the invention relates to a drum segment, a drum, and a brush roller with such a mounting device.
