Holder for a rotary tool, for example one hole saw

Holder for a rotary tool, for example a hole saw, which holder is formed with an essentially rotationally symmetrical holder body comprising a rear drive end, for example adapted to be clamped in a chuck of a drilling machine, and a front connection end having a connection thread for the connection of the rotary tool, that the holder comprises an axially movable thrust collar which is placed at the connection end and around the same and which has a contact surface facing the connection end of the holder and that the contact surface at least partly, directly, or indirectly, abuts against the assembled rotary tool , that the holder furthermore comprises an axially movable operating means assembled around the holder body and a number of restraint elements placed in one or more spaces in the holder body and which restraint elements in a first axial position of the operating means are prevented by the operating means from radial movement in said spaces and which restraint elements in a second axial position of the operating means are free to make a radial movement in said spaces, characterized in that wherein the restraint elements upon said radial movement also are displaced a distance in the axial direction and that each one of said spaces for the restraint elements is limited in the axial direction by a front limiting wall as well as by a rear limiting wall, which two limiting walls constitute parts of the holder body.