I had a big bin of combing waste. It is left over from combing Romney and some Rambouillet. I had thought to felt it, but I carded it on the drum carder, and am spinning it semi-worsted into ~ 5,600 ypp/ ~ 9 tpi semi-worsted singles. These are being plied up into 10-ply/ 500 ypp Aran weight yarn.
The singles are not up to my standards for 2 or 3 ply, but make a nice 5-ply. However, they make a very nice 10-ply. More plies tend to average out defects in the singles. And they can be spun very fast -- almost like woolen -- 5 or 6 hundred yards per hour.
At that rate, the 10-ply yarn for a sweater is only 30 or 40 hours work. This yarn is ALMOST FREE. Free yarn, who can pass up free yarn?! It will not be as durable as full worsted, but it is much more durable (and warmer) than ANY mill spun Aran yarn. (e.g., http://www.aransweatermarket.com/knitting/aran-wool/natural-white-wool) It is a softer and less durable than a full worsted yarn, but it is likely to last me for the rest of my life. And, these yarns are soft enough for my wife.
Forty hours of spinning and 60 hours of knitting - I can have a real hand spun 10-ply /hand knit Aran sweater in ~ 100 hours. On the other hand, the finished yarn does have more than 100 tpi in it - and therefore is only really practical if your wheel spins fairly fast. I am running my bobbin faster than 3,500 rpm to produce single at a rate of 8 or 10 yards per minute. (I figure 48 minutes of actual spinning per hour.) This actually faster than I was producing the loom web which was only 2,800 ypp/ 5 tpi, and opens up new options for finer loom yarns. (You know that I am still learning to spin!!) I know spinners who spin faster, but I do not know any that spin singles this fine, this fast, on a sustained basis. However, I have no doubt that generations of nimble fingered spinsters spun finer singles faster. For example, I see no technical reason why the spinners of Flanders circa 1520 could not have spun faster -- they had the tools, and more skills than I will ever acquire.
One advantage of spinning the 5,600 ypp singles is that most of the veggy material drops out. These singles are fairly clean, but if I was spinning 2 or 3-ply Aran weight (e.g., 1,000 or 1,500 ypp singles) , they would be full of VM. The finer singles allow more VM to drop out and allow a better yarn with less effort.
At these speeds, when spinning Irish Tension, there is enough take up that the yarn will tend to bury (even with the tiny AA #0 flier), thus DD with a fixed differential rotation speed results in higher productivity, despite the tendency to break off at any hesitation in the drafting process. Spinning at this speed is rather like hand feeding a hungry dragon; it always wants more, without pause. I could spin slower, but that would raise the time commitment for the yarn, and that would make it less like free yarn.: - (
This does nothing to diminish my love of yarns plied up from commercial warp yarn, but it offers options.