According to typical inventive practice, a cable is grasped by a Kellum grip and is positioned through the topside “V”-notch of an “M”-structure. Two wires engage pulleys and a ratchet distanced from the pulleys. The pulleys are joined with a grip plate, attached at an axial end of the Kellum grip. The ratchet is joined with a ratchet plate, proximate and/or attached to the “M”-structure. The “M”-structure has joined therewith three blade wheels having cutting orientations in the same linear direction. The blade wheels are situated interiorly and perpendicularly in correspondence to the geometric sides of the inverted triangle defined by the “V”-notch. Each blade wheel is adjustable to suit the diameter of the cable positioned through the “V”-notch. Ratcheting of the wires moves the ratchet plate and hence the “M”-structure, resulting in creation via the blade wheels of three parallel slices in the cable along its axis.

A flat harness is machined by providing a punching machine that includes a first punching device and a second device, and forming different types of hole portions in the shape on the insulating portion of the flat harness in a die cutting process by using the first punching device and the second punching device.