Abstract: A honing machine has a stone expansion system in which the honing stones are expanded radially via wedges by radial movement generated by a d.c. wedge motor. The motor (13) is driven by a constant-current amplifier (50) which provides a driving current according to a required stone pressure (a). This determines the torque of the motor during honing. A speed input (g) sets a required approach speed and from this is derived a control signal which controls an on/off controller (55). This causes the output current of the constant-current amplifier to be choppped, therby controlling speed as the stones approach the wall of the bore while allowing control of torque during honing.

Abstract: A honing machine in which a micro-processor controls reciprocation with respect to a work-piece of a spindle which carries honing stones, the micro-processor being associated with a memory unit which holds an acceleration profile in terms of position/time and being programmed to control reciprocation in accordance with the required acceleration characteristics. Variable stroke parameters and required mid-stroke speed are input from a console and the system ensures symmetrical honing under controlled acceleration regardless of any conflict between selected stroke length and mid-stroke speed.