Abstract: To maintain a constant cutting pressure in the cutting wire of a stone cutting wire saw for efficient sawing, the sensor of a radio frequency inductive proximity switch is mounted near the bowed section of the sawing wire to monitor its degree of bow. When the bow of the wire is reduced after cutting down into the stone, modification of the sensor signal activates an output circuit of the proximity switch control module which turns on a wire down feed means to quickly reestablish the proper degree of bow and wire cutting pressure. The activation distance is so small that, for practical purposes, constant wire cutting pressure is maintained.