A Mc Morran balance is a helpful tool when you need to know yardages of large amounts of yarn. As a hand spinner, I can usually measure my yarn using my winder. It’s when I put my weaving hat on that a Mc Morran balance can be truly helpful. The balance uses just a short sample of the yarn to determine the overall length of the entire lot.

The Mc Morran balance is a very simple tool composed of an acrylic box that has been fitted with a metal pin or fulcrum and an arm. The pin and arm can be stored within the box when it is not in use.

To use the balance, place it along the edge of a table or countertop to allow the yarn sample to hang freely in case it is longer than the base of the balance. Drape a 2 foot length of yarn over the arm of the scale. Proceed to trim the yarn in small doses until the arm is balanced. Remove the balanced length of yarn from the arm of the scale and measure its length in inches. Multiply the length times 100 to arrive at the yards per pound measurement of the yarn. (For example: 7 inches of yarn would be 700 yards per pound.)

To determine the overall length of the yarn, weigh the entire lot and multiply the number of pounds by the yards per pound measurement that you read from the scale. It is best to use a scale that measures in fractional pounds (2.15lbs) rather than ounces(2# 1oz.).

Okay, you know me, I just can’t leave it at this! How on earth does this work? It is so brilliantly simple! The yarn balance is set to measure 1/3600th of a pound (this converts to 126mg). The 36 in the factor is to convert the inches to yards while the 100 is a nice round multiplier that brings the sample length of yarn required to a much more manageable level. With this in mind, we now have another option. Do you have a scale that will measure 126mg? If you can determine how long of a yarn sample it takes to weigh that amount, you can achieve the same results using a scale. Most postage scales are not calibrated to be this accurate, certainly not the one I use. So, for now, I’ll have to stick with my Mc Morran balance.