Ply

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For the chess and go term, see ply (chess).

For the polygon data file format, see PLY (file format).

A ply is a strand or layer of material, such as yarn, rope, plastic, wood, or paper. Plywood is so called because it is a laminate of several thin layers of wooden material. Two-ply toilet paper has two separable layers, each about as thick as single-ply, affording greater comfort and convenience without a commensurate increase in the risk of clogging the toilet.

Contents 1 Ply with respect to yarn 1.1 Plying handspun yarns 1.2 Machined yarns 1.3 Novelty yarns

[edit] Ply with respect to yarn

Plying is a process used to create a strong, balanced yarn. It is done by taking two or more strands of yarn that each have a twist to them and putting them together. The strands are twisted together, in the opposite direction than that in which they were spun. When just the right amount of twist is added, this creates a balanced yarn, which is a yarn with no tendency to twist upon itself. Almost all store bought yarns are balanced, plied yarns.

A two ply is thus a yarn plied from two strands, a six ply is one from six strands, and so on. Most commercial yarns are more than a two ply. Embroidery floss is generally a six ply, for example.

[edit] Plying handspun yarns

When hand-spinning, there are two common ways to ply a balanced yarn: regular and Navajo.

• Regular plying consists of taking two or more singles and twisting them together, the opposite way. This can be done on either a spinning wheel or a spindle. The most important thing to remember though is that the twist must go the opposite direction. If in spinning the single the wheel was spinning clockwise (which is called a "Z" twist, as on any given side the fibres appear to cross diagonally in the same direction as the diagonal of a "Z"), in order to ply it the wheel must spin counter-clockwise (an "S" twist). This is because otherwise you are not balancing the twist, just twisting it more. The concept is similar to when a heavily twisted piece of yarn is folded, and it twists up on itself. It is most common for singles to be spun with a "Z" twist, and then plied with an "S" twist.

• Navajo plying consists of making large loops, similar to crocheting. First make a loop about 8 inches long through the loop on the end on the leader. (A leader is the string left on the bobbin to spin off of.) Start spinning all three strands together in the opposite direction than that they were spun in. When only 2 to 3 inches remain of the loop, pull a new loop of yarn through the loop, and continue spinning. The new loop should be around 7 inches long. Repeat this process until the yarn is all plied. Only one single is necessary, and if the single is already dyed this technique allows it to be plied without ruining the colour scheme. This technique also allows the spinner to try to match up thick and thin spots in the yarn, thus making for a smoother end product.

Most spinners (who use spinning wheels) ply from bobbins. This is easier than plying from balls because there is less chance for the yarn to become tangled and knotted if it is simply unwound from the bobbins. So that the bobbins can unwind freely, they are put in a device called a Lazy Kate, or sometimes simply kate. The simplest lazy kate consists of wooden bars with a metal rod running between them. Most hold between three and four bobbins. The bobbin sits on the metal rod. Other lazy kates are built with devices that create an adjustable amount of tension, so that if the yarn is jerked, a whole bunch of yarn is not wound off, then wound up again in the opposite direction. Some spinning wheels come with a built in lazy kate. Picture of lazy kates, with tension device.

[edit] Machined yarns

Machines that ply yarn use the 'regular' method mentioned above. The main difference is that instead of humans, gears control the intake making sure that the strands all have the same tension and the same length. Other than that, the process for plying is exactly the same.

[edit] Novelty yarns

Many novelty yarns make use of special plying techniques to gain their special effects. By varing the tension in the strands, or the relative sizes of the strands, or many other factors different effects can be achieved. For example, when a soft, think strand is plied against a tightly twisted thin strand, the resulting yarn spirals. Another example is the boucle, which is a yarn where one strand is held loosely and allowed to make loops on the other yarn while plying.