Abstract: A tool such as a drill bit which has a generally cylindrical shank for insertion in a tool receiver or holder of a rotary percussive machine or other rotary machine, such as a drilling machine. The shank has a curved surface portion and a flat surface portion of rectangular configuration, the flat surface portion lying between the ends of the shank. When the shank is inserted in a tool receiver of a rotary percussive machine (not shown), driving elements thereof engage and act on the flat surface to provide driving torque to the tool, which is thereby rotated.

Abstract: A unitary thick walled spacer S supports an anchor rod (15) for engagement in an expansion body (6). The tubular spacer S has a first part P of greater diameter than its remaining part P', with the part P' in slide fit engagement in the expansion sleeve (1), and the part P abutting, at its free end, a washer (17) and the head of the anchor rod (15). An annular rim M formed between the parts P and P' of the spacer S, is arranged, prior to use, a distance X from the expansion sleeve (1). As clamping down is performed in a receiving socket, the spacer part P' slides inside the expansion sleeve so progressively closing the gap X. The arrangement is so designed that in any particular application, the rim M at most just barely comes into contact with the expansion sleeve (1) so avoiding uselessly and detrimentally loading the spacer S.

Abstract: A tool such as a drill has a cylindrical shank for insertion in a tool holder of a rotary percussive or other rotary machine, such as a drilling machine. The shank has a first surface extending transversely of the shank from a point of intersection with the periphery thereof and a second surface extending from the first surface at the end of the first surface remote from the point of intersection of the first surface with the periphery of the shank to a point of intersection with the periphery spaced from the point of intersection of the first surface with the periphery. There are two sets of first and second surfaces spaced apart on opposite sides of the longitudinal axis of the shank.The first and second surfaces are flat. The second surfaces are radial and arranged on the same diameter. A plane through the longitudinal axis of the shank at substantially 90.degree.