Yarn is nothing except fibers to which twist has been added. The sole purpose of any spinning device, whether it is a wheel or a spindle, is to add twist to fibers to create yarn.

With a spindle, it is very easy to see how twist is added to the fibers. Every time the spindle rotates once, one twist is added. It is a little more difficult to understand exactly how a bobbin and flyer spinning wheel inserts twist into the fibers.

Here is how this works on a bobbin and flyer wheel. Every single depression of the treadle causes the flyer to turn X number of times. And every time the flyer completes one revolution, one twist is inserted into the fibers. Say that every time the wheel is treadled, the flyer rotates 5 times. This means that 5 twists will enter the fibers.

Taking it one step further, say that the spinner is drafting 1inch of fibers for each depression of the treadle. This means that there are 5 twists going into each inch of yarn If the spinner drafted only half an inch per treadling, then there would be 10 tpi (twists per inch). A 2-inch draft would give only 2 and a half tpi.

Controlling the amount of twist going into the yarn is the first step towards controlling the type of yarn you spin. The key to understanding how much twist is entering your yarn for each treadling is to know the ratio(s) of your spinning wheel.

The ratio of a spinning wheel is simply the number of times the flyer turns for each rotation of the drive wheel. It is very easy to figure this out and, for those of you whose eyes are glazing over at the mere hint of the dreaded M word, there is not even any math involved. Tie a piece of yarn around one arm of the flyer and position this arm at its uppermost position. Then put a little sticky dot at the uppermost position of the drive wheel. Check to be certain that both the marked flyer arm and the sticky dot line up in their uppermost positions and then slowly turn the drive wheel by hand while counting the rotations of the flyer arm. You have just found your ratio! Make a note of this number. It is usually written 10:1 or 6.5:1. The first number is the number of times the flyer turned and the second (after the colon) indicates that the drive wheel turned just one time. Note: on some wheels, the flyer will not turn unless there is some yarn threaded through the orifice and held under slight tension while the drive wheel is turned. If your wheel is one of these, simply thread it just as you would to spin, and hold a bit of tension on the yarn while you turn the drive wheel and count the number of times the flyer turns.

Your wheel most likely has more than one ratio, so figure the ratio for each whorl. The whorls are the round things with grooves that either fit on the shaft of the flyer or are located at the ends of the bobbins or both. Each one will be a different size and each one, or each combination or flyer whorl and bobbin whorl, will give a different ratio. The larger the whorl, the lower the number of twists that will be inserted; the smaller the whorl the larger the number of twists inserted per treadling. Knowing the ratios you have available enables you to use all of your whorls to help control the amount of twist entering your yarn.