For All Cordage and Wire Needs ROPE GLOSSARY

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# Rope Glossary

 CONVERSION CHART SIZE Inches x 25.40 = Millimeters Milimeters x 0.03937 = Inches LENGTH Feet x 0.3048 = Meters Meters x 3.2808 = Feet WEIGHT Pounds x 0.4536 = Kilograms Kilograms x 2.2046 = Pounds YARDAGE Pounds per 100 Feet x 1.4882 = Kilograms per 100 Meters Kilograms per 100 Meters x 0.6720 = Pounds per 100 Feet STRENGTH Pounds Force x 4.448 = Newtons Kilograms Force x 9.806 = Newtons Pounds Force x 0.00448 = Kilonewtons Tonnes Force x 2204.6 = Pounds Force Pounds Force x 0.00045359 = Tonnes Force TEMPERATURE Celsius = . 55556 x ( Fahrenheit – 32 ) Fahrenheit = 1.8 x Celsius + 32
ABRASION RESISTANCE:
The ability of a fiber or rope to withstand surface wear and rubbing due to motion against other fibers or rope components (internal abrasion) or a contact surface such as wraps on a winch drum (external abrasion), which can be a portion of the rope itself.

BLOCK CREEL:
A method of rope making where a given length of rope is produced from a ropemaking machine where all the subcomponents of the rope structure are continuous without splices. The term arises from filling all creels or bobbins to maximum (block creels) and ending rope making when the first one empties.

BRAID:
n. A rope or textile structure formed by a braiding process. v. The intertwining of strands in a braiding process to produce a tubular rope structure.

BRAID, DOUBLE:
A rope constructed from an inner hollow braided rope (core) which has another hollow braided rope constructed around its exterior (cover). Core and cover may be either plain or twill braid and both share any load on the rope, but not necessarily in equal amounts. Also called “braid-on-braid.”

BRAID, HOLLOW
(Also: Braid,Single; Braid, Diamond): A single braid rope construction of either plain or twill braid. The center is hollow. On the surface all strands are parallel to the axis.

BRAID, SOLID:
A cylindrical braid in which each strand alternately passes under and over one or more of the other strands of the rope while all strands are rotating around the axis with the same direction of rotation. On the surface, all strands appear to be parallel to the axis.

BRAIDER SPLICE:
In a braided rope, the continuation of a single interrupted strand (or multiple strands) with another identical strand, which is braided from the same carrier. The interrupted and replacement strands are arranged in parallel over some distance, and are buried, or tucked, into the braid so as to secure them into the braid. To maintain maximum strength, the strands should overlap one another for a sufficient distance.

BREAKING LENGTH:
A convenient term for comparing the strength-to-weight ratio of textile structures from one product to another. The calculated length of a specimen whose weight is equal to the breaking load.

BREAKING STRENGTH:
For cordage, the nominal force (or load) that would be expected to break or rupture a single specimen in a tensile test conducted under a specified procedure. On a group of like specimens it may be expressed as an average or as a minimum based on statistical analysis.
Note: Breaking force refers to an external force applied to an individual specimen to produce rupture, whereas breaking strength preferably should be restricted to the characteristic average force required to rupture several specimens of a sample. While the breaking strength is numerically equal to the breaking force for an individual specimen, the average breaking force observed for two or more specimens of a specific sample is referred to or used as the breaking strength of the sample.

BREAKING STRENGTH, MINIMUM:
Cordage Institute standard. A value based on a statistically significant number of breaking load tests and the standard deviation used to establish the minimum value.

CLASS I ROPE:
Rope constructions produced with non high modulus fibers that impart the strength and stretch characteristics to the rope which have tenacities of 15 grams/denier (gpd) or less and a total stretch at break of 6% or greater. Typical Class I ropes are produced with traditional fibers such as: olefin (polypropylene or polyethylene), nylon, and polyester. These fibers can be used in combination or singularly in the various rope constructions such as: 3-strand, 8-strand, 12-strand braids, double braids, or coredependent braids.

CLASS II ROPE:
Rope constructions produced with high modulus fibers that impart the strength and stretch characteristics to the rope which have tenacities greater than 15 grams/denier (gpd) and a total stretch at break of less than 6%. Typical Class II ropes are produced with: HMPE (Dyneema® fiber or Spectra®), Aramid (Technora® or Kevlar®), LCP (Vectran®), PBO (ZYLON®), and Carbon fibers. These fibers can be used in combination or singularly in the various ropes constructions such as: 3-strand, 8-strand, 12-strand, double braids, or core-dependent braids.

CORE-DEPENDENT BRAIDS:
Cover braided rope constructions that utilize an internal core member or members to create the strength and stretch characteristics of the rope. The primary function of the external cover braid is to contain the core or cores and create the degree of rope firmness desired. Based on the fiber or combination of fibers used in the cover braid, the following characteristics of the rope can be altered: coefficient of friction, wear resistance, specific gravity, and heat resistance due to friction. Core-dependent braided ropes typically have internal strength members produced with parallel bundled fiber cores, a single braid core, multiple braid cores, or multiple 3 strand cores. This type of rope construction can be produced with traditional fibers, high modulus fibers, or combinations of both fiber groups, and offers the potential of creating a wide range of design parameters.

CYCLE LENGTH:
The length along the axis required for a strand to make one revolution around the rope.

The loss of desirable physical properties by a textile material due to some process of physical/chemical phenomenon.

DENIER:
The system used internationally for the numbering of silk and man-made filament yarns, except glass yarns. It is the primary unit for determining the size of a yarn and is based on its linear density. Officially, it is defined as the number unit weights of 0.05 grams per 450-meter length. Denier is equivalent numerically to the number of grams per 9,000 meters. In the English numbering system, 1 denier equals 4,464,528 yards to the pound. Denier is also used to indicate the thickness of a man-made fiber staple. For example, a staple is said to be 3 denier if 1,488,176 linear yards of the staple (were it continuous) would weigh one pound. The metric equivalent is Tex, the grams mass of 10,000 meters of yarn.

Any rapidly applied load that increases the load significantly above the normal static load when lifting or suspending a weight. Dynamic effects are greater on a low elongation rope such as manila than on a higher elongation rope such as nylon, and greater on a shorter rope than on a longer one. Also, any rapidly applied load to cordage that may change its properties significantly when compared to slowly applied loads.

EXTRUSION:
For polymer filaments. The process of producing filaments by forcing a polymer through a die.

FATIGUE:
The tendency of a material to weaken or fail during alternate tension-tension or tension-compression cycles. In cordage, particularly at loads well below the breaking strength, this degradation is often caused by internal abrasion of the fibers and yarns but may also be caused by fiber damage due to compression. Some fibers develop cracks or splits that cause failure, especially at relatively high loads.

FIBER:
A long, fine, very flexible structure that may be woven, braided, or twisted into a variety of fabrics, twine, cordage or rope.

FINISH:
An oil, emulsion, lubricant or the like, applied to fibers to prevent damage during textile processing or to improve performance during use of the product.

HYDROLYSIS:
The attack of the water ions on polymeric molecules, which results in polymer chain scission and loss of the fiber's physical properties.

LAID ROPES:
Ropes made by twisting of three or more strands together with the twist direction opposite that of the strands.

LAY LENGTH:
The actual distance required to make one complete revolution around the axis in any element in a strand, cord or rope.

LIQUID CRYSTAL POLYMER (LCP):
A thermoplastic multifilament yarn spun from a proprietary liquid crystal polymer. LCP fiber is five times stronger than steel and ten times stronger than aluminum for its weight. It has no creep and excellent chemical resistance.

MONOFILAMENT:
A yarn consisting of one or more heavy, coarse, continuous filaments produced by the extrusion of a polymeric material suitable for fiber production.

MULTIFILAMENT:
A yarn consisting of many fine continuous filaments produced by the spinning of a polymeric material suitable for fiber production.

NAPPING:
A process that raises the surface fibers of a fabric, cord or rope by means of rapid passage over metal surfaces.

NOMINAL SIZE:
A designation that has been determined by the measurement of another property. For rope, diameter is considered a nominal property and is based upon the measurement of the linear density of the rope in accordance with some standard.

NYLON (PA) FIBER:
A manufactured fiber in which the fiber-forming substance (polyamide) is characterized by recurring amide groups as an integral part of the polymer chain. The two principal types of nylon fiber used in rope production are type 6.6 and type 6. The number in the type designation is indicative of the number of carbon atoms separating the acid and amine groups in the polymer chain.

pH:
Value indicating the acidity or alkalinity of a material. A pH of 7.0 is neutral; less than 7.0 is acidic, and more than 7.0 is basic.

POLYESTER (PET) FIBER:
A manufactured fiber in which the fiber-forming substance (polyester) is characterized by a long chain polymer having 85% by weight of an ester of a substituted aromatic carboxylic acid.
Rope inc. 3 Strand Polyester Rope Page

POLYETHYLENE (PE):
A polyolefin resin, produced from the polymerization of ethylene gas, and used in the production of manufactured fiber. Polyethylene is similar to polypropylene in its properties but has a higher specific gravity and a lower melting point.

POLYETHYLENE, EXTENDED CHAIN:
A polyolefin fiber that is characterized by the gel spinning of a very high and narrow molecular weight distribution fiber to produce extremely high tenacity material. The strength of the fiber is approximately 10 times that of steel on a weight-for-weight basis.

POLYMER:
A long chain molecule from which man-made fibers are derived; produced by linking together molecular units called monomers.

POLYPROPYLENE (PP):
A polyolefin resin, produced from the polymerization of propylene gas, and used in the production of manufactured fiber. Polypropylene may be extruded into a number of fiber forms for use by the ropemaker.

ROPE, EIGHT-STRAND PLAITED:
A rope of which the strands are generally plaited in pairs, and mainly used for marine purposes.

ROPE, FIBER:
A compact but flexible torsionally balanced structure produced from strands that are laid, plaited or braided together to produce a product that serves to transmit a tensile force between two points. Generally greater than 3/16" diameter.

SPECIFIC GRAVITY:
Ratio of the mass of a material to the mass of an equal volume of water.

SPLICE:
The joining of two ends of yarn, strand or cordage by intertwining or inserting these ends into the body of the product. An eye splice may be formed by using a similar process to join one end into the body of the product.

STRAND:
The largest individual element used in the final rope-making process and obtained by joining and twisting (or braiding) together several yarns or groups of yarns.

STAPLE:
Natural fibers of cut lengths from filaments of man-made fibers. The staple length of natural fibers varies from less than 1" for some cotton fibers to several feet for some hard fibers. Man-made fibers are cut to a definite length, usually about 1-1/2" but occasionally down to 1", so they can be processed on the cotton, woolen and worsted systems. The term staple (fiber) is used in the textile industry to distinguish natural or cut length man-made fibers from filament.

TENSILE STRENGTH, MINIMUM:
A value based on a large number of breaking force tests representing a value that is two standard deviations below the mean. See: Breaking Strength, Minimum.

TORQUE:
A force or a combination of forces that produces or tends to produce a twisting or rotating motion. When used in describing the performance or characteristic of yarn, the term torque refers to that character which tends to make it turn on itself as a result of twisting.

TWIST:
The number of turns about the axis applied to a fiber, yarn, strand or rope over a given length to combine the individual elements into a larger and stronger structure. The direction of rotation about the axis denoted as “S” (left hand) or “Z” (right hand) twist.

TWIST, BALANCED:
In a plied yarn or cord, an arrangement of twist which will not cause the yarn or cord to twist on itself when held in the form of an open loop.

TWISTING:
The process of combining two or more parallel textile elements by controlling the lineal and rotational speeds of the material to produce a specific twist level.

The working load that must not be exceeded for a particular application as established by an engineer, supervisor, regulatory or standards setting agency.

YARN:
A generic term for a continuous strand of textile fibers, filaments or material in a form suitable for intertwining to form a textile structure via any one of a number of textile processes.

YARN, SINGLE:
The simplest textile structure available for processing into rope, twine or cordage.

YARN, PLIED:
A yarn formed by twisting together two or more single yarns in one operation in a direction opposite to the twist direction of the single yarns to produce a balanced structure.