About Wire Rope
Our Specialty, explained
Wire Rope has come a long way since our founding in 1945. This section is dedicated to educating the consumer about the types, applications and intricacies of wire rope.
Types of Wire Rope
Wire Rope has many types, cores and constructions. Different types of core include, IWRC(Independent Wire Rope Core), NFC(Natural Fiber Core), SFC(Synthetic Fiber Core), SPC(Solid Plastic Core) and Strand Core.
IWRC, as the name implies, has a core made out of a wire rope that has a its own core. IWRC is your run-of-the-mill general purpose rope.
NFC is a woven core made of hemp or sisal fibers. This type of rope handles being bent better than alternatives, and can retain lubricant better since it soaks into the fibers of the core. This type is most susceptible to moisture or chemical damage. It is typically used when flexibility is more important than strength. This is the type of core typically found in amusement drive cables and slings.
SFC is a plastic core, being made from taking a vinyl solution, firing a UV laser from below, and pulling the fiber right out of the solution, a type of additive manufacturing. SFC maintains the strand's place along the wire rope, and also allowing for the rope to be more shock resistant and flexible. SFC is also more resistant to rust and corrosion, making it better for outdoor applications than NFC.
SPC is similar to SFC, but is made of a solid piece of plastic in the core of the rope. This is the newest type of wire core, typically made after the strands around the rope are already made, and the plastic is molded to fit the inside of the strands around the core. This method allows for the best level of shock absorption, as it fills the space between the strands, which is typically the culprit when it comes to a noisy rope. This type of core is best used in circulating railroads, chairlifts, and haul ropes. This type of core is only used in applications where rope shortening is only acceptable in certain, plannable periods.
WSC is similar to IWRC, while being made of a single strand instead of a wire rope with a core. This would be ideal for applications like aircraft cable, or something that is under less tension than a rope that is certified for overhead lifting. The core strand may be counted as another strand, so there may be a wire rope with six outward-facing strands that may be "seven strand" because they're counting the center as the seventh strand.
Rotation Resistance - What is it? Do I need to worry about it for my application?
Rotation resistance is a factor to consider when ordering a wire rope, and failing to order rotation-resistant wire rope result in rope torque, this results in a tendency for the rope to unlay itself. Every wire rope will develop torque when loaded. This can result in the usability and working load of the wire rope being diminished.
Different types of rotation-resistant rope are detailed in ASTM A1023, with the three categories being determined based on the number of outer strands, and the amount of layers between the core and the outermost strands of the rope. There is at least two layers of opposite, twisted strands.
​ Rotation resistance is determined by the way that the core, strands, and any middle layer of cable are laid on the core. If the strands and core are rotated in different directions, it is rotation resistant.
Wire rope that is designated as rotation-resistant is susceptible to "core pops" and bird caging. Another thing to take caution of when handling rotation-resistant rope is kinking and crushing. The nature of the rope, to have strands running in opposite directions, results in some inner-strand nicking between the two layers, resulting in the overall lifespan of the rope being diminished.
The most common use for rotation-resistant rope is on cranes, where one end of the rope is required to be able to spin freely, and flexibility isn't a concern. Mobile cranes are most commonly going to require rotation-resistant rope, but all tower cranes require rotation-resistant wire rope.
6 x 26 WS IWRC Strength and Weights Chart (inches)
