Grinding machine

A grinding machine, comprising

• a bed;
• a pair of guide columns fixedly mounted on said bed, with a plurality of guide surfaces being formed on said guide columns in a common vertical plane;
• a tool mounting head disposed between said guide columns, supported for vertical movement by supporting means comprising elevating means coupled to said tool mounting head and operable to adjust the vertical position of said tool mounting head, sensing and control means for detecting any vertically directed force applied to said elevation means by said tool mounting head, and an operating member coupled to support said tool mounting head and controlled by said sensing and control means for applying a vertically directed force to said tool mounting head having a direction and magnitude such as to compensate for said vertically directed force applied to said elevation means by said tool mounting head, said tool mounting head being further provided with hydrostatic bearing means for restraining said tool mounting head against movement other than in a direction parallel to said plane of said guide surfaces of the guide columns;
• a tool shaft rotatably mounted in said tool mounting head;
• drive means for rotating said tool shaft;
• a grinding tool fixedly mounted on said tool shaft;
• a workpiece slide mounted on said bed for sliding motion traversing a guide surface formed on said bed;
• and
• means for mounting at least one workpiece holding jig upon said workpiece slide.