So last week I showed you the yarn I spun up at Yarn School. One of the things that we discussed was the difference between woolen and worsted spinning, both in terms of fiber prep (which seems to be most important) and spinning technique (which is where you get the "semi"). Woolen yarn is only produced when you start with a carded fiber prep, worsted yarn comes from combed prep. Since most of the commercially available fibers come in top form (even if they are referred to as roving), 99.9% of the spinning I've done has been worsted or semi-worsted. Until I went to Kansas.
The purple and black mini-skeins were spun from hand carded rolags. The brown single was spun from a batt. The major difference between these two preps is that hand carded rolags force you to spin a woolen yarn with the fibers more or less traveling in a circle around the circumference of the single, rather then longitudinal along the single. Batts can also be spun with circumferential fibers or longitudinal. Both preps give you a yarn that is fuzzy because the ends of the fibers are free to stick out rather then being smoothed into the single and caught by the twist. You can see the fuzzies in the above picture.
This is an example of worsted spinning. The fiber prep was combed top, which I spun with a short forward draw, smoothing and compressing the single as the twist entered. The fibers in this yarn run parallel to the axis of the single, so the ends are trapped and the yarn is smooth. This is a good way to get a very strong, durable, hard wearing yarn, which was perfect for this stuff, which became my first pair of knee-socks.
On the right is the yarn I spun at Yarn School - this is a semi-worsted yarn. The prep was combed top, but I pulled off chunks and spun them long-draw from the fold, thereby jumbling the fiber orientation. On the left is the yarn I spun up from my H^4 swap fiber: spun with short forward draw, worsted yarn. Nice and smooth, no fuzzies. I'm calling it Cotton Candy for the colors, and I think Devil has designs on it for something.
Cotton Candy stats:
Domestic wool combed top from Poppy Flower Fibers, 4 oz
Spun worsted style, 2 ply, ~12 wpi, 183 yds/4 oz.
One other point about worsted vs. semi-worsted. Worsted style spinning got me 183 yds from 4 oz. Semi-worsted at a similar wpi got me 83 yds/1.1 oz. So the semi-worsted spinning gets you more yardage since the yarn is less dense due to trapped air. So now I'm on the hunt for some commercial roving to buy so I can get going on some sweater yarn!