Most spinners spin yarn and use it without measuring it—and there is nothing wrong with that. But you may one day find yourself in a situation when you need to describe your yarn to someone else. Or maybe you want to make a similar yarn. It is handy to know the grist of the yarn. Wraps per inch is a good place to start—but it won’t tell you everything you need to know about your yarn.
Yards per pound (ypp) will give you a better idea of how much yarn you need to make for a given project, or how much fiber you need to start with if you want to spin yarn for a particular pattern.
Measure yards per pound by weighing your yarn and counting the yards after you’ve skeined it on a niddy-noddy. Or you can measure a length of yarn on a McMorran balance. Actually, it is a good idea to do both.
Measuring Yards Per Pound (if you know the yardage)
You can figure yards per pound by determining how many yards and how many ounces are in a skein. You’ll have to do a little calculating—there’s one little trick I retained from math classes in high school that is very useful.
If your yarn contains 220 yards and weighs 2 ounces, and you want to know how many yards are in a pound of this particular yarn, you multiply 220 × 16 which equals 3,520, then divide that by 2 to get 1,760 yards. I’m a visual person—so seeing the algebra proportions equation like this helps me remember it when I need it.
220 yd/2 oz = X yd/16 oz
X = 1,760 yd
Measuring Yards Per Pound with a Balance
If you have a McMorran balance, then all you need is a strand of the yarn you’re measuring to determine the yards per pound. With a McMorran balance, place the arm of the balance in the groove at the top of the box with the notched end facing you and hanging over the edge of a table. Place a length of yarn in the notch—it should be heavy enough that it causes the arm to hang down. With sharp scissors, start cutting little bits of the yarn off one end and then the other (I usually place a wastebasket underneath to catch the cut ends) until the arm balances horizontally. When the arm is balanced, lay the (now shorter) yarn next to a ruler and measure without stretching it. Multiply the inches by 100 and you have yards per pound for your yarn! For example, a yarn that measures 17.5 inches is 1,750 yards per pound. And of course, there is a McMorran balance for metric measurements as well.
Lay the remaining length of yarn along a ruler, multiply by 100, and the result is the yards per pound of the yarn!
This article first appeared in Spin Off Summer 2008.