Spud and Billie
Fiber Diameter and How It Affects You
Average fiber diameter is the most important wool fiber property in the context of quality and value. An increase in fiber diameter results in increased fabric harshness, flexural rigidity and abrasion resistance, while its propensity for felting decreases. In carding and combing, fiber breakage and noil production decrease as fiber diameter increases. Diameters larger than 30 microns or 50s in grade are stiff enough to be "prickly" to most peoples skins and, therefore, not suitable to wear next to the skin. Yet these and courser fibers make wonderfully, durable rugs and upholstery. The fiber diameter of wool is expressed by two different systems, one is based on the English Worsted Yarn Count System (spinning count or wool grade) and the other is a scientific method that measures the actual diameter of the fiber in microns.
Spinning Count or Wool Grade
It is interesting to note that the numbers used to express wool grade are the same as those used in the English (Bradford) Spinning Count System. When used to quantify yarn count, the number and letter 's' represent the number of 560 yard lengths of yarn that can be spun from one pound of top. Each 560 yard length is called a hank. Top is a clean, continuous untwisted strand of combed wool in which the fibers lie parallel, with short fibers having been combed out as noil. At one time, it was theoretically possible to manufacture 64s yarn from 64s wool. Because of increased machine speeds and greater productivity, this is no longer practical in today's worsted industry. The double meaning of the symbol for count has been a source of confusion for many people involved with the U. S. sheep and wool industries. This system is being replaced by a measurement of diameter in microns.
The spinning count varies from finer than 80s wool like you find on superfine Merinos bred in Australia; to coarser than 36s fleece like you find on Cotswold, Lincoln or Romney breeds.
Micron Measurement

Micron is shorthand for micrometer, which is equal to one-millionth of a meter. The average diameter range for the major sheep breeds varies from under 17 microns to over 40 microns. Merinos and Rambouillets typically have micron counts between 18 (80s)and 22. These are the breed types that would use the light fabric to prevent pilling. Corriedales and Columbias range from 23 (60's) to 25 (58's) microns and they could use either fabric. I used the heavy on most of my Corriedales but some of my older ewes used the light fabric. In my experience, sheep fiber becomes a bit finer and has a bit shorter staple as the sheep gets up there in age. Cotswolds, Lincolns and Romneys have a micron range from 32 (46's) to 40 (36's) microns and they thrive in the heavy covers and their wool has such luster.


Clean Wool SellsHome Contact

Regular Order FormHow To MeasureHorned Order Form

FAQFiber & Sheep LinksFabricHorned Cover Info

Camelid Clothes for Alpacas & Llamas

All materials, images, content and page design copyright © 1999 - 2017 by Rocky Sheep Company.
All rights reserved. No material may be copied, distributed, reproduced or held in any
electronic storage device in whole or in part without prior written permission.