Posted by Clint Dixon on Wednesday, December 18, 2002 at 11:44AM :
In Reply to: Re: Winch Cable posted by Dana on Wednesday, December 18, 2002 at 9:25AM :
Hey Dana,
Yes, there are a lot of different kinds and grades of wire rope. Here is some information from a TM 5-225 Rigging And Engineer Hand Tools dated 1942:
"Wire rope is classified by size, contruction, and grade."
"The size of wire rope is the diameter of the smallest circle inclosing the cross section. Because of use (stretching), the original diameter eventually decreases 1/8 to 1/64 of an inch."
"Wire rope is classified as to construction by the number of strands, number of wires per strand, strand construction, lay, core, and fabrication. Rope is designated by the number of strands per rope and the number of wires per strand, thus: 6 by 19 (6 strands per rope, 19 wires per strand). Various types of rope construction in common use are: 3, 4, 6, 8, 9, and 18 strand. Various types of strand construction in common use are: Coarse Laid, Standard Flexible, Special Flexible, Extra Flexible, Non rotating, Galvanized Rope, Independent Wire Rope Center, and Wire Strand Center." (All types of strand construction, except the last two, have a hemp core center.) "Hemp cores are usually made of manila or Java fiber, laid up into a three- or four-ply cord. Wire cores may be either a single strand or a wire rope. Lay refers to the twist of the wires and strands of the rope. There are two lays in a rope; the strand lay, or the twist of the wires in the strand; and the rope lay, or the twist of the strands in the rope." (Lay describes the direction strands "lay" in the rope - Right or Left. When you look along a rope, strands of a Right Lay rope follow a right-turning pattern. Left Lay is the opposite. The relationship between the direction strands lay in the rope and the direction wires lay in the strands is either Regular Lay or Lang Lay. In a Regular Lay rope, wires lay opposite the direction of the strand. In a Lang Lay rope, wires lay in the same direction as the strands.) "Five combinations commonly used in hoisting rope are: 1. Right regular lay - rope lay right, strand lay left. 2. Left regular lay - rope lay left, strand lay right. 3. Right lang lay - rope lay right, strand lay right. 4. Left lang lay - rope lay left, strand lay left. 5. reverse lay - rope lay right or left, strand lay alternately right or left."
"There are six common grades of wire rope: Iron, Traction steel, Cast steel, Mild plow steel, Plow steel, and improved plow steel." (Iron being the weekest and Improve plow steel being the strongest).
This information is probably more than most of us will ever need to know when it comes to purchasing wire rope for the winches on our Power-Wagons. It does however, give one a sample of the vast array of choices available back in 1942. It has only gotten worse over the past 60 years. If you really want to get confused, just take a look in a current Slings and Rigging Catalog from a company that services heavy industry.
I went with a 250' of 7/16" diameter Right Lay-Regular Lay fiber core rope for the MU2 winch on my WDX. The fiber core makes the rope flexible so it comformes to the drum better than wire core rope. The fiber core also holds lubricant, if you are inclined to subscribe to the theory supporting lubricating wire rope. Fiber core rope is more susceptible to flattening out on the inner layers, but this is really only a problem if you fail to keep the rope wound tight on the drum between use. Also keeping the rope wound tight to the drum ensures that 250' will fit correctly. It does not take much slack on the drum for 250" to fill it up and start spilling over the sides. The Regular Lay helps the rope to slide over objects without the wear of a Lang Lay rope
Other sizes of cable, and the lengths required to fill the drum to 2/3 full of capacity, specified by Braden for the MU2 are: 1/4" - 700', 5/16" - 450', 3/8" - 316'. Sizes too small for a Power-Wagon, but this gives an idea of how different sizes of rope correlate into different lengths for the same drum diameter.
Clint
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