Abstract: A machine spindle includes a casing and a clamping mechanism disposed in the casing. The clamping mechanism includes front and rear drawbars which are relatively movable axially within the casing. A gas spring biases the rear drawbar rearwardly, and a force transmitting mechanism transmits such rearward motion to the front drawbar for moving the front drawbar rearwardly. In response to its rearward movement, the front drawbar actuates a clamp for clamping a tool. The gas spring includes a housing disposed in the casing and defining a gas chamber having a front wall through which the rear drawbar extends. The gas spring also includes a piston disposed in the gas chamber for axial movement therein. The piston is releasably connected to a rear end of the rear drawbar by a releasable coupling disposed in the chamber.

Abstract: A threading tool for generating a thread in a workpiece, includes a threading part which defines a longitudinal axis. A cooling channel extends inside of the threading part along the axis to a front end surface thereof for supplying a coolant. Longitudinally extending passages are disposed in an outer periphery of the threading part for the return of coolant exiting the coolant channel. A diversion element is positioned at the front end surface for diverting the exiting coolant in a laterally outward direction along the front end surface toward the passages.

Abstract: A body is at least partially coated with one or more refractory layers of which at least one layer is of a fine grained &kgr;-Al2O3. Said &kgr;-Al2O3 layer has equiaxed grains with an average grain size of <0.5 &mgr;m. The Al2O3 layer also has at least one sublayer containing Al, Si and O. The fine grained &kgr;-Al2O3 microstructure is obtained by periodically introducing a silicon halide, preferably SiCl4, during the Al2O3-process.