Abstract: A recess in a workpiece is honed by a honing tool that is reciprocated in a succession of strokes back and forth in the recess as it is rotated about an axis of the recess. The stones of the honing tool are pressed by at least one hydraulic cylinder against the workpiece with a pressure that is incrementally increased after each stroke. To this end a pilot-controlled primary pressure-limiting valve is connected between a pump and the cylinder, and a plurality of multiway valves can connect any of a plurality of differently preset secondary pressure-limiting valves to the pilot port of the primary valve. The cylinder piston can have a pair of unequal effective faces each exposed in a respective cylinder compartment so that during a first operation stage both compartments are pressurized to the same extent for differential action and during a second operation stage only one of the compartments is pressurized.

Abstract: A plurality of honing stones carried at the lower end of a honing spindle are rotated about the spindle axis and vertically stroked in a cylindrical recess to be honed. The upper end of the spindle is connected to a cross-member vertically displaceable on a machine frame and connected to one run of an endless chain whose other run is connected to a counterweight and which is spanned over a sprocket carried by a hydrostatic motor. A variable-displacement reversible pump connected to the motor changes the stroke direction in accordance with position signals produced by a position sensor in the machine. The force with which the tools bear on the workpiece is increased and decreased jointly with the tension in the chain.

Abstract: A honing machine has a floating honing tool which is vertically reciprocal and rotatable about a vertical axis. A workpiece frame under the machine has a pair of workpiece-clamping stations each of which has an upper plate and a lower plate formed with a throughgoing aperture for passing the tool. The confronting faces of these plates are provided with centering formations and the lower plate can be displaced up toward the upper plate to clamp a tubular workpiece against it. Each upper plate can be displaced horizontally out of the way to allow the respective station to be loaded and unloaded. The workpiece frame itself can be displaced horizontally under the machine in order to align either of the stations with the tool so that as a workpiece in one station is being honed the other station can be emptied and reloaded.