I thought Ily's comment about sock thickness on my last post deserved further discussion. She remarked: "I've always been a little confused by knitted socks, since all the ones I've seen are too thick to fit inside shoes. Did you manage to solve that problem?"
The answer is: yes, through the magic of weight and gauge. There are, roughly, about seven "weights" of yarn, ranging from laceweight to super bulky.* Many novelty socks are knit in bulky or worsted-weight yarn, making them unsuitable for wear with regular shoes. (Socks knit with worsted are often called "boot socks.") The trick is getting special sock yarn, which is very, very small indeed. Sock yarn is the next step up from laceweight, a category generally called "fingering weight." Proper sock yarn is distinguished from regular old fingering weight by its blend of fibers. Compare the labels.
The Baby Ull is 100% wool, the Fortissima is 75% cotton, 25% polyamide. Even the most diehard, natural-fiber freak has to use a yarn specifically made for socks (or reinforce the chosen yarn with special thread)--otherwise the sock won't hold its shape or stand up to wear and washing. So proper sock yarn is a) fingering-weight and b) made of the right stuff. You can see that the Tofutsies I used for the Waving Lace socks is very skinny indeed. Here it's superimposed next to a random worsted-weight yarn.
The other aspect of making socks to fit is gauge. If you knit very light yarn on comparatively large needles, you get a loose, open fabric: the principle behind knitting lace. (More on this later.) In order to get a fabric that will work for socks, you have to knit sock yarn on the proper needles, which are very. very. small. The Waving Lace socks were knit on size 1/2.25 mm needles; most socks are knit on 0/2.00 mm, 1, or 2/2.75 mm needles. Here's a size 0 needle next to a dime, for comparison.
When sock yarn is knit on small needles, the result is a thin, dense fabric that holds its shape after washing. Yay, socks! Generally, these socks will be too thick for wear with women's dress shoes but just fine for wear with sneakers or everyday shoes. Fun fact: back when handmade socks were still the norm, many were knit on teeny-tiny needles, the equivalent of today's sizes 000/1.5 mm or 0000/1.25 mm.** And you thought socks were too fiddly to knit nowadays.
So, long story short, yes, these socks are thin enough to wear with regular shoes, and so are most that I make these days. My initial sock experiments were thicker (and quicker)--SQ's socks, for example, were made of a bulky chenille that couldn't be worn with shoes. (Or did you ever try, SQ? Inquiring minds want to know!)
*I may have to restrain myself physically from ordering when Posh Yarns restocks next week. Must . . . resist . . . laceweight . . .
**I got this from Knitting Vintage Socks, by Nancy Bush. If you mention it at a cocktail party and the next guy over happens to be an expert on antique knits or needle manufacture or something, tell him that that's what SHE says.