B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
B24B7/00—Machines or devices designed for grinding plane surfaces on work, including polishing plane glass surfaces; Accessories therefor
B24B7/10—Single-purpose machines or devices
B24B7/16—Single-purpose machines or devices for grinding end-faces, e.g. of gauges, rollers, nuts, piston rings
B24B7/167—Single-purpose machines or devices for grinding end-faces, e.g. of gauges, rollers, nuts, piston rings end faces coil springs