Machine Design

What are Standard Cable Constructions?

All wire rope and mechanical cable are fabricated from individual wires helically twisted into a strand. Most small commercial cables are made using a core as their central member, with a given number of strands helically wrapped around the core. Most cables use as their core a solid wire, strand, or an independent wire rope core. All cable is made using two or more strands as the basis of its construction. The number of wires in a strand and the number of strands in a cable are controlled by the construction that is specified.

Cable is specified by the number of strands in the cable by (X) the number of wires in each strand. Commercial quality "aircraft grade" type cables are most typically 1X7, 1X19, 7X7 and 7X19. The most popular strand is 1X7, which consists of 1 center core wire, which is straight, and 6 wires helically stranded around the core. This basic strand is used to make 1X19, 3X7, 7X7 and 7X19 cable. Flexibility of the same diameter cable is a function of the number of wires in the cross section with 1X7 being the stiffest and 7X19 being the most flexible standard construction. Each cable use must be analyzed to determine the most suitable construction for the application.

All cables consist of individual wires, a center core and outer strands as shown. Most "aircraft grade" type cables are made with preformed wires (except for the center wire of a strand) and preformed strand. Preforming allows the cable to lay straight and reduces the tendency of the wires to pop or fly apart when the cable is cut mechanically.

Cable can be stranded with either a right or left hand lay, which is the direction that the outer strands are "laid" around the core. All commercial quality "aircraft grade" cable is made and stocked in right regular lay configuration. Wires in the strand are laid to the left and each strand is laid to the right. The length of lay is the dimension in inches for one strand, or one wire to make one helical revolution around the center core. The length of lay is determined by the specification for the particular strand or cable, or by the application.

Standard Cable Constructions
Commercial Quality 'Aircraft Grade" Galvanized and Stainless Steel Size Range Description Typical Uses/Applications Construction 3/64" thru 1/4" Dia. Basic strand for all concentric cable, relatively stiff in large diameters offers the least stretch. Basic strand, straight pull-pull assemblies, tension members. 1 x7 1/32" thru 1/2" Dia. Smooth outside diameter, fairly flexible, resists compressive forces, strongest construction in sizes above 3/32" diameter. Tension members, guy lines push-pull controls, pull-pull controls. 1 x19 1/32" thru 1/2" Dia. Durable,higher flexibility and abrasion resistance. Good general purpose construction for strength and flexibility. In small diameters can be used over pulleys, pull-pull cable controls 7 x7 1/16" thru 1/2" Dia. The strongest and most flexible of cables, with greatest stretch. Over pulleys, drive cables, reciprocating applications, and lanyards. 7X19


TM Cable Mfg. & Assy. Co. Inc.

Hide comments


  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.