Abstract: A rotation controller controls a rotation mechanism for rotation of a spindle. A movement controller causes, while the spindle is rotating, a feed mechanism to bring a cutting tool into contact with a workpiece to cause the cutting tool to cut the workpiece. The rotation controller controls a spindle rotation speed so as to accelerate or decelerate the rotation of the spindle, and the movement controller brings the cutting tool into contact with the workpiece after the rotation controller starts the rotation of the spindle, and separates the cutting tool from the workpiece while the spindle rotation speed is put under the acceleration control or deceleration control exercised by the rotation controller.

Abstract: A non-metallic self-supporting aerial optical cable is comprised of a suspension wire and optical cable which are made of non-metallic material and have non-metallic sheaths. The optical cable and suspension wire are maintained substantially parallel by a number of spaced apart connecting members. The optical cable is allowed to sag between the connecting members in order to withstand tensile forces which result from wind, snow and the like.