McMorran Yarn Balance - Sivia Harding Knit Design

Or, How a McMorran Yarn Balance Changed the Way I Look at Yarn

The McMorran Yarn Balance is a useful but small device that looks positively dinky at first glance. It consists of a plastic box with a small notched plastic arm sitting on top, swinging freely.

When a sample piece of yarn is hung on the notched arm so that it balances, that length times 100 equals the number of yards per pound of that yarn. For instance, if the yarn is 10 inches long, the yarn weighs 1000 yards per pound (ypp). Once your ball (or balls) of yarn is weighed, a simple calculation reveals the number of yards you have to work with. This can be an enormously useful way to measure unknown amounts of yarn you have in your stash.

According to an article by Alden Amos* that appeared in Spin-Off magazine, the McMorran Balance was designed by H. McMorran, B.Sc, of the Scottish College of Textiles in Galashiels, Scotland. It is a fixed weight balance, which means that a piece of yarn placed on the notched end of the plastic arm is weighed against a fixed weight, in this case 1/3600 of a pound. Thus the yards per pound of any yarn can be calculated with a McMorran Balance and a scale. Leave it to the Scots to figure out something this simple yet ingenious!

Measuring yarn by yards per pound is also a useful way to look at yarn in its own right. Yards per pound tells you how heavy the yarn is, how thin or thick. Spinners use this information to check the uniformity of their spinning as they progress in a project. The yarn industry uses it as a standard, so if you buy millend yarn or yarn on cones, you will often see this measurement used.

According to Yarn Forward’s** website, the guidelines for wool yarn in yards per pound are as follows:
Lace or 3-ply “baby” 2,560 ypp
4-ply fingering 1,920 ypp
DK to worsted weight 1,280 ypp
Aran weight 853 ypp
Chunky weight 682 ypp

These rather odd yardage amounts come from the other industry standard of “yarn count” which is a more complicated system and won't be covered here. But this chart is useful as a general indicator of how thick or thin the yarn is, or its “grist.”

The other factor that needs mentioning is accuracy. Most sources cautioned against expecting more than 20% accuracy. However, Marion Topping and I were able to get very accurate readings from the McMorran Balance by first calibrating it against yarns of known quantity. We measured Shetland jumper weight, Dale of Norway's Heilo, and a couple of other well-known yarns. We knew what the label stated they should weigh, and what the Balance reported was consistently 10% under this weight. However, when we stretched the yarn very slightly while measuring its length, we got very accurate results.

I would recommend taking some time with your measuring at first if you decide to purchase a McMorran Balance. It will definitely pay off. Happy Balancing!

* “Yarn Grist: An Excerpt from ‘The Alden Amos Big Book of Handspinning’” by Alden Amos, Spin-Off Magazine, Summer 2001
** Yarn Forward is a Canadian knitting store with branches in Ottawa and Kanata, Ontario.