Monday, January 28, 2008


There are different handling methods for wire rope. Here are some methods.

Kinking - When loose wire rope is handled, small loops sometimes form in the slack portion of the rope. If you apply tension to the rope while these loops are in position, the loops will not straighten out but will get sharp kinks, resulting in unlaying of the rope. You need to straighten these loops out of the rope before applying a load. After a kink has formed in wire rope, it is impossible to remove it, and the strength of the rope is damaged at the point where the kink occurs.

Unreeling - When removing wire rope from a reel or coil, you should be sure to rotate the reel or coil. If the reel is mounted, the wire rope may be unwound by holding the end and walking away from the reel. If a wire rope is in a small coil, you can stand the coil on end and roll it along the deck, barge, wharf, or ground. Remove any loops that may form, although rotating the reel or coil avoids causing loops to form.

Seizing - You should seize all wire rope before cutting it. If the ends of the rope are not secured, the balance of tension is disturbed. Maximum use cannot be made on wire rope when some strands carry a greater load than others.

    Annealed wire is recommended for the seizing. You should tighten the turns of the annealed wire rope so that they do not have to tighten them when the ends are being twisted together. The ends should be twisted together at one end of the seizing so that the completed twist can be tapped into the groove between two strands where it is less likely to be knocked off.
    There are three formulas for determining the number and length of seizings and the space between them. When a calculation results in a fraction, use the next larger whole number. These formulas are based on a 3/4-inch diameter wire rope.
    The number of seizings required equals about three times the diameter of the rope. For example: 3 x 3/4 = 2 1/4 or 3 seizings. Because the rope will be cut, six seizings are required so that there will be three on each rope end after the cut.
    The length of a seizing should be equal to the diameter of the rope. For example: 1 x 3/4 = 3/4 or 1 inch. The seizings should be spaced a distance apart equal to twice the diameter. For example: 2 x 3/4 = 1 1/2 or 2 inches apart.

    Cutting - Wire rope can be cut with a wire rope cutter, a cold chisel, a hacksaw, bolt clippers, or an oxyacetylene cutting torch. To seize the wire rope, insert it into the cutter with the blade between the two central seizings, close the locking device, then close the valve on the cutter. The handle should be pumped to build up enough pressure to force the blade through the rope.

    Use bolt cutters on wire rope of small diameter. Use the oxyacetylene torch on wire of any diameter. Cutting with the hacksaw and cold chisel is slower than cutting with the other tools and equipment.

    Coiling - You may need to take a length of wire rope from a reel and coil it down before using it. Small loops or twists will form if the wire rope is coiled in a direction opposite to the lay. To avoid loops, you should coil right lay wire rope clockwise and left lay wire rope counterclockwise. When a loop forms in the wire, they should put a back turn.

"Putting a back turn in wire rope"

    Size of Sheaves and Drums - When a wire is bent over a sheave or drum, two things could happen. Each wire is bent to conform to the curvature, and the wires slide against each other lengthwise because the inside arc of the rope against the sheave or drum is shorter than the outside arc. The smaller the diameter of the sheave or drum, the greater the bending and sliding. You should keep this bending and moving of wires to a minimum to reduce wear. The minimum recommended sheave and drum diameter is 20 times the diameter of the rope. For example, for 5/8-inch rope: 20 x 5/8 = 12 1/2-inch sheave. If a 12 1/2-inch sheave is not on hand, you should use the next larger size, don't use a smaller size.

    Lubrication - Wire rope is lubricated as it is manufactured. The lubricant generally does not last throughout the life of the rope, which makes relubrication necessary. Crater "C" compound is recommended, but personnel may use oil on hand rather than delay lubrication. Crater "C" compound should be heated before it is put on the wire rope. You can use a brush if to apply lubricant. If a brush is not available, try a sponge or cloth, but look out for fishhooks or broken wires.

    Reversing Ends - It is good to reverse or cut back ends to get more service from wire rope. The wear and fatigue on a rope is more severe at certain points than at others. Reversing distributes stronger parts of the rope to the points getting wear and fatigue. To reverse ends, remove the drum end, put it in the attachment, and then fasten the end taken from the attachment to the drum. Cutting back the ends has the same effect, but not as much change is involved. In reversing ends, you should cut off short lengths of both ends to remove the sections with the greatest wear.

    Storing - Wire rope should be coiled on a spool for storage. Its grade, size, and length are on a tag attached to the rope or spool. Wire rope should be stored in a dry place to reduce corrosion. Don't store it with chemicals or where chemicals have been stored because chemicals and their fumes can attack the metal. Always clean and lubricate wire rope before storing it.

    Cleaning - You can remove most of the dirt or grit on a used wire rope by scraping or steaming. Rust should be removed at regular intervals by wire brushing. Clean your rope before lubricating to remove foreign material and old lubricant from the between the strands and from the spaces between the outer wires. This lets the lubricant to enter the rope.