Ply

From Wikipedia, the free encyclopedia

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.

Plying yarn is done by pulling yarn from two or more bobbins and twisting it together, in the opposite direction than that in which it was spun. This creates a balanced yarn, a yarn with no tendency to twist itself. Almost all store bought yarns are balanced, plied yarns.

When hand-spinning, there are two common ways to ply: 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.

Machines that ply yarn use the 'regular' method. The main difference is that gears control the intake, rather than a human. Otherwise the process for plying is exactly the same.