Plow Steel Wire Rope Plow steel wire rope is unusually tough and strong. This steel has a tensile strength of 220,000 to 240,000 psi. Plow steel wire rope is suitable for hauling, hoisting, and  logging. Improved Plow Steel Wire Rope Improved plow steel wire rope is one of the best grades of rope available and is the most common rope used in the NCF. This type of rope is stronger, tougher, and more resistant to wear than either mild plow steel or plow steel. Each square inch of improved plow steel can stand a strain of 240,000 to 260,000 pounds. This makes it especially useful for heavy-duty service, such as  on  cranes  with  excavating  and  weight-handling attachments. LAYS OF WIRE ROPE The term lay refers to the direction of the twist of the wires in a strand and to the direction that the strands are laid in the rope. In some instances, both the wires in the strand and the strands in the rope are laid in the same direction; and in other instances, the wires are laid in one  direction  and  the  strands  are  laid  in  the  opposite direction,  depending  on  the  intended  use  of  the  rope. Most manufacturers specify the types and lays of wire rope to be used on their piece of equipment. Be sure and consult  the  operator’s  manual  for  proper  application. Five different lays of wire rope are shown in figure 13-4. The five types of lays used in wire rope are as follows: . Right Regular Lay: In right regular lay rope, the wires in the strands are laid to the left, while the strands are laid to the right to form the wire rope. . Left Regular Lay: In left regular lay rope, the wires in the strands are laid to the right, while the strands are laid to the left to form the wire rope. In this lay, each step of fabrication is exactly opposite from the right regular  lay. . Right Lang Lay: In right lang lay rope, the wires in the strands and the strands in the rope are laid in the same direction; in this instance, the lay is to the right. . Left Lang Lay: In left lang lay rope, the wires in the strands and the strands in the rope are also laid in the same direction; in this instance, the lay is to the left (rather than to the right as in the right lang lay). Figure  13-4.—Lays  of  wire  rope. . Reverse Lay: In reverse lay rope, the wires in one strand are laid to the right, the wires in the nearby strand are laid to the left, the wires in the next strand are to the right, and so forth, with alternate directions from one strand to the other. Then all strands are laid to the right. LAY LENGTH OF WIRE ROPE The length of a rope lay is the distance measured parallel to the center line of a wire rope in which a strand makes one complete spiral or turn around the rope. The length of a strand lay is the distance measured parallel to the center line of the strand in which one wire makes one complete spiral or turnaround the strand. Lay length measurement is shown in figure 13-5. Figure 13-5.—Lay length of wire rope. 13-3