It is simple. It takes a fair amount of skill, but it is simple.
First learn to spin worsted singles that are a bundle of only 20 fibers (e.g., spin count yarn). Practice with with different kinds of wool, so that you can spin a single of 20 fibers regardless of the kind of wool. In the old days, this skill was expected of all competent spinners. Wool buyers and wool inspectors (such as G. Chaucer), were all competent spinners. In England, circa 1600, spinners were expected to be competent after 2 years of training.
As you draft spin count yarn watch your drafting triangle so that you can easily recognize when 20 fibers are feeding into the yarn.
Now, you can take your twisty stick and spin a 20 fiber yarn from any wool sample. By eye and experience you can then easily estimate the spin count of the wool, and the chart below will translate the spin count to microns.
The chart below makes it clear that micron count can be estimated from the traditional spin count. Is it as accurate as the modern lab micron count? Not at all, but it was good enough for wool trade, and a textile industry producing fine cloth from hand spun yarns for a thousand years. Some of those yarns were were much better than anything hand spinners produce today. Fancy lab analysis of my wool does not make me a better spinner. A cheap twisty stick will provide enough information about a bin of wool for even the best hand spinner to work their best skill on the wool.
|USDA Standard Wool Specifications|
|Type of Wool||Old Blood Grade||Numerical Count Grade||Limits for Average Fiber Diameter (microns)||Variability Limit for Standard Deviation Maximum (microns)|
|Fine||Fine||Finer than 80’s||<17 .70="" td="">17>||3.59|
|Very coarse||Braid||Coarser than 36's||>40.20||--|
|1The blood system for most all useful purposes is outdated and has not been recognized by USDA since 1955.|
The idea is that the difference in thickness between the fibers in two different wools will be no more than about 20 microns and may only be a few microns. That difference is hard to see with the naked eye and may be obscured by the variability in the fibers. However, the spun yarns provide a statistical sampling that averages out the variability; and, the difference between the thickness of an 80 count yarn and a 40 count yarn is about 50 microns, which is clearly and easily visible to the human eye. Discrimination of rather fine increments in spin count (e.g., 42's v. 44's) can be achieved by having a reference collection and comparing the wool being tested to those standards. (A reference collection is otherwise known as a stash with labels.)
As you go down this lane, you will find that the better sorted and graded a wool is, the finer and easier it spins. Blends of fibers are harder to spin. The blend may be desirable for the final textile, but it requires more effort from the spinner. This is less of an issue, if you are spinning at grists of less than 20,000 ypp (40/1 Nm).
Historic wool garment fabric ran 20 to 70 epi and when we do the math (Look in Alden Amos) we know that many of the yarns (warp and weft) were in the 40 to 80 count range. Hosiery was traditionally knit from yarns based on 40 count singles. Spinning fine yarns for weaving is what competent spinners did. If you can do it, you are a spinner.
If you must blend, blend fibers of the same spin count. I spin a lot of warp from a commercial blend of 56 count wools; and, it spins well. Everybody that sees the hanks asks, "What kind of wool is this?" In this case, the blending is to produce a uniform top and the fiber sizing is more uniform than is found in roving from individual flocks or even individual fleece. In fact it spins so well that I am starting to think of 56 count weaving singles. As tabby that would be, Ouch . . .6,000 yds of single per yd^2 of fabric - 20 hours of spinning for every yd of fabric. Perhaps, I need a 20 dent reed.
I will freely admit that while I have been able to spin at the spin count for a few years, mostly the samples were small, in the range of a few hundred to a few thousand yards. (And yes, I called those early 560 yard hanks weighing only 6 grams, "My little shits". There was good reason, the first ones were not properly blocked - they were not pretty. A lot of people that cannot spin 80s laughed at me. The joke is on them. They still cannot spin 80s, but I can spin pretty 80s. All it takes is thousands of yards of practice and learning to block hanks of fine singles.) Now, I am coming to grips with spinning pounds and pounds of wool at its spin count. Am I a spinner? Not sure yet. I will know when I have woven a bolt of shirting from my hand spun.
The craft is broken. We will rebuild it thread by thread, my friends, thread by thread.