In addition to the things I've learned about setting up my wheel I've come up with a sort of training program for my spinning. Here's a description of what I'm trying. Note that I have only a very basic wheel, only a single treadle, no lace flyers or high-speed whorls or anything. So spinning thin is going to be slow! I figure I want to learn how to do it first, before I go out and start souping up my machine to make the stuff faster.
First, I measure the WPI of my favourite sock yarn and I knit up a small sample (20st x 20 rows or so) on my favourite sock needles (2mm). I measure the gauge and make a little card that I write everything on, and tie it to the sample. This sample is the "goal". Then, I start spinning!
1. I purchased a hank of (cheap) sock roving (100g) from KnitPicks ("stroll roving" - undyed) - a superwash merino / nylon blend. I made it CHEAP to be sure that I wouldn't mind screwing it up. This is not going to turn into socks. This is for practise only! Note that this particular blend is quite slippery and very fine. I find that it's hard to spin woolen, so the short forward draft I described here is what I find easiest to use. If you use different roving (ex. something crimpy like southdown) you might find that a different drafting technique suits better.
2. I divided the 100g hank into 5-10 small portions and am making "mini-skeins", trying different spinning and plying techniques. I started with double, then moved to triple, and finally 4-ply trials. I've found this book particularly helpful for yarn construction ideas.
3. I use a small portion to spin up fine singles. Then, I measure the WPI. I visualize sewing thread while spinning and try to make it as thin as possible. Then, I ply it and measure the WPI again. Then I wash the yarn and when it's dry, measure the WPI yet again. Then I critically examine the yarn. Is it thin enough? Well-plied? Strong enough? I take my sock knitting needles and use the yarn to knit up a small swatch, and I measure the gauge of my knitting when I'm done. I write down all these measurements (WPI counts, knitting gauge, needle size) on a little paper tag, and tie it to the cast-off tail of the sample. I unply part of the cast-on tail so I can see the singles and/or the 2-ply. Now I can use this sample to guide me in my next spinning session!
4. Then I move on to the next small portion . If I didn't like my first sample, I can adjust the number of treadles per inch of drafting (which changes the amount of twist in the yarn). If there's too much twist, I draft out a longer piece per treadle. If there's not enough twist, I draft out less per treadle. I find it easier to adjust what my hands are doing, than my feet. Somehow, my feet get into a particular rhythm/speed with the treadling, which is hard to break out of (must be all the biking I do). Once I'm satisfied with how thin I'm getting the yarn, I try a different plying technique. I first tried chain or Navajo plying, and then measured all the WPIs again and knit up another sample. I'm not very happy with my Navajo plied yarn - it's pretty inconsistent!
[Navajo/chain-plied 3 ply sample - note thick/thin parts which don't pass muster with me]
As I've gone through the portions, I find I'm spinning thinner and thinner. The focus on the measurements really seems to drive home that I need to take very small "bites" when drafting.
I've even tried a cable-4 ply: first spin the singles Z, then (over)ply 2 singles together in the opposite direction (S), and then ply that back on itself in the Z-direction. I find it easiest to do the first ply to the "balance point" (ie. make a nice-looking balanced yarn), and spin the yarn onto another bobbin, spinning it up to double the amount of twist (rather than trying to overtwist on the first go-round). I've found that 4-ply cable produces really nice even yarn for me, even if it is still a bit on the thick side for my expectations. It's the most consistent I've done.The knit sample has a larger gauge than the 3-ply (I need to spin even thinner to get the same gauge!).
[4-ply cable sample in merino-nylon]
[4-ply cable sample in Southdown - each of those threads is 2-ply]