Continuing Looking at Wool Types & Micron Counts

Previously on another blog post, I was looking into micron counts and wool types in order to learn about "micron counts" and why they are or not important. I also wanted to research some of the wools that fall into the Fine/Medium/Long (Coarse) categories as suggested by the guidelines so that I would have a better idea when planning on projects on exactly what wool types would be best suited for it.

There are apparently two books on the subject of wool types that I need to acquire:The Knitter's Book of Wooland In Sheep's Clothing: A Handspinner's Guide to Wool.These have been recommended on the Ravelry boards by a multitude of people.

However, Ravelry and the general Internet has been a wealth of information. You just need to go to many sites and piece things together; and even then, you still have an incomplete picture.

But, here's what I've determined thus far in terms of wool (I'm not including things like silk and plant fibers):

Fine wools (16- 22 microns): most Alpacas, Merino, Cormo, Rambouillet, (some) BFL(x), fine shetland(x), camel, angora, possum, quiviut, cashmere, vicuna

Medium wools (22- 31 microns): Corriedale(x), Falkland(x), BFL(x), mohair(x), (inner) Icelandic(x), Shetland(x), Dorset, Cheviot, Jacob

Long wools (31- 36 microns):Romney(x), Wensleydale, Border Leiscter, Lincoln(x)

(X)s mark those wools I've already spun as part of my Spinning Study.

When correlated with the information from the previous post, it gives me an idea of what projects to use with different types of wool:

16-19 Fine worseted & intimate wear

19-23 Apparel, outerwear, quilt batting / felts

23-28 Sweaters, light upholstery coatings, fiberfill

28-32 Upholstery, tapestries, some carpets

32-38+ Carpets, industrial use.

Obviously, these are only guidelines. There's nothing preventing anyone from using one type of wool to make something out of the "category",

Micron Count System

As a relatively new spinner, I had to do a bit of research on this concept of ‘microns’ as it relates to wool softness. I’ve seen how some on Ravelry use micron as a determining factor for their fleeces, wools, etc. So, I did a bit of research on the subject.

In general, the Micron system uses the measurement of a micron (1 millionth of a meter or 1/25,000 of an inch) to determine how the type of wool (either ‘fine’ or ‘coarse’). However, the “micron” count does not necessarily mean is of good quality. The micron count of a lot or fleece of wool uses the “average micron count”. But, apparently, this count can be deceptive.

For example, if you have a lot of wool, where
• 50% of the fiber = 35 microns
• 50% of the wool = 15 microns,
• the average micron count for that LOT is 25 microns.
• So, you’d have a lot that’s a mixture of both “coarse” and “fine” wool.

Consequently, the additional measurement of the amount of variation in fiber diameter (the Standard Deviation Column) can give you a better insight to the quality of wool. So a fleece or lot of wool with its individual fibers closer in diameter could be considered a more “quality” wool [1]

Type of Wool	Micron System	Maximum Standard deviation (microns)
Fine	Under 17.70	3.59
Fine	17.70 - 19.14	4.09
Fine	19.15 - 20.59	4.59
Fine	20.60 - 22.04	5.19
Medium	22.05 - 23.49	5.89
Medium	23.50 - 24.94	6.49
Medium	24.95 - 26.39	7.09
Medium	26.40 - 27.84	7.59
Medium	27.85 - 29.29	8.19
Medium	29.30 - 30.99	8.69
Coarse	31.00 - 32.69	9.09
Coarse	32.70 - 34.39	9.59
Coarse	34.00 - 36.19	10.09
Very Coarse	36.20 - 38.09	10.69
Very Coarse	38.10 - 40.20	11.19
Very Coarse	Over 40.20

There are no hard-and-fast rules on how different types wools should be used, but there is a general guideline: [2]

• 16-19 Fine worseted & intimate wear
• 19-23 Apparel, outerwear, quilt batting / felts
• 23-28 Sweaters, light upholstery coatings, fiberfill
• 28-32 Upholstery, tapestries, some carpets
• 32-38+ Carpets, industrial use.

Of course, from reading various articles, going micron mad is probably not the best way to raise animals or determine the best wool needed. There’s the role of “crimp” in determining uniformity or density in wool, and is a factor in selecting a fleece. But that’s another topic for another time.

So conclusion? Micron count should be used as a guidelines for merely determining “softness” of a given wool or as a consideration when selecting a fleece or wool. It shouldn’t be the end-all-be-all of the decision process.


[1] http://msuextension.org/publications/AgandNaturalResources/MT198380AG.pdf
[2] From the Navajo Sheep Project: http://navajosheepproject.com/images/pdf/wool/woolgrading.pdf