Wire Rope Cable and Considerations

All wire rope cables, wire rope cable assemblies and cable lanyards are manufactured from single wires that are twisted into main strands. The most standard constructions of wire rope are 1×7, 1×19, 7×7, and 7×19, which represent number (#) of strands by number (#) of wires in each strand.

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The most common strand is the 1×7 construction which includes one straight center strand with six wires wrapped around it. This basic 1×7 construction is the basis for 1×19, 7×7, and 7x19 cables. The 1×7 construction is the stiffest, while the 7×19 is one of the most flexible. SA Miniature Stainless Steel cables range from .009 to .045 inch. Our commercial quality galvanized and stainless steel cables range from .032 to 1/4 inch diameter.

Wire Rope Cable / Wire Rope Assemblies Construction Table

Straight Tensile Load Tensile Load With Flexing Over Pulley
Recommended Construction 1x19 7x19 7x19 Coated and Lubricated
Minimum Construction 1x7 7x7 7x7

Wire Rope Cable Considerations

When selecting the appropriate wire rope cable for your wire rope assemblies or control product, there are a few factors which need to be considered:

CONSTRUCTURAL STRETCH:

All wire rope cables have spaces between each strand and wire. When a load is applied, the spaces between the wires are reduced and the wire rope cable will grow in length. The amount of the growth is determined by the load applied, length of the cable, and construction of the cable. Motion Control Technologies’ cable assemblies can be proofloaded (by applying a load of 60% of minimum cable breaking strength to the assembly) to eliminate any constructional stretch.

ELASTIC STRETCH:

The elastic stretch is an elongation of the cable wires when a load is applied. This can be a significant factor when the yield point of the wire is surpassed. Please contact Motion Control Technologies to determine the elastic stretch of a specific cable.

MINIMUM BREAKING STRENGTH:

The minimum breaking strength of the cable is referred to as the minimum tensile strength. This is measured in pounds (lbs) or kilograms (kgs) and should be based on the maximum working load and safety factor. The recommended minimum safety factor ration is 10:1 which represents the minimum breaking strength TO the maximum working load.

Other factors to determine when designing the correct cable for your requirements are CABLE DIAMETER,CABLE MATERIAL, and COATING ON THE CABLE.

Flexibility Tensile Strength Stretch Resistance Relative Cost Corrosion Resistance
Highest 7x19 1x19 1x7 7x19 Coated Stainless Steel
Medium-High 7x7 1x7 1x19 7x7 Bare Stainless Steel
Medium Low 1x19 7x19 7x7 1x19 Coated Galvanized Steel
Lowest 1x7 7x7 7x19 1x7 Galvanized Steel