Abstract: A machine for cutting plate-shaped workpieces, incorporates a tool guide (7), an operating handle (13), and a cutting tool (6) which revolves along the tool guide (7). By moving the operating handle (13), the tool guide (7) with its cutting tool (6) can be shifted from an idle position into an active position. In its idle position the cutting tool (6) is disengaged from, and, in its active position it is engaged in, the workpiece to be processed. Provided between the operating handle (13) and the tool guide (7) is a variable ratio transmission mechanism (14, 18) with a transmission ratio which varies with the movement of the operating handle (13) as a function of the position of the tool guide (7) and its cutting tool (6) relative to the workpiece.

Abstract: A hand-held milling machine (1) has a cutting tool (9, 10) which protrudes from a machine support (3) on the side facing the workpiece. A screw-type clamping mechanism allows the cutting tool (9, 10) and the machine support (3) to be positionally adjusted relative to each other by the relative rotational movement of clamping sections (6, 18) on both sides around a drive axis (13) in the direction of the projection of the cutting tool (9, 10) relative to the machine support (3). The clamping sections (6, 18) are positioned opposite each other in the radial direction of the drive axis (13). A tensioning device (35) allows the two clamping sections (6, 18) on both sides to be secured against relative rotational movement around the drive axis (13).

Abstract: A rivet has a head and an elongated shank of generally circular cross section extending axially therefrom. The head has a periphery including a multiplicity of spaced portions projecting radially outwardly of the periphery of the shank and at least three guide portions between these projecting portions which provide guide surfaces extending axially of the rivet with their root surface disposed in substantial axial alignment with the periphery of the shank. The head may have a configuration shaped like a dome, or an inverted frustoconical element, or a prism, and the guide portions can be arcuate in transverse section or rectilinear. The rivet shank may have a groove along its length to facilitate securing of the workpieces therewith without requiring upsetting of the shank, and the shank may have a sharp cutting edge at its free end to facilitate penetration of the workpieces to avoid the necessity for predrilling and the like.