There is a class of knitters that knit as a social pastime. Social pastimes have conventions that function like the rules of a game. Like a game, social pastimes have winners and losers. (see for example the work of Eric Bern, http://www.ericberne.com/structure-and-dynamics-of-organizations-and-groups/ , http://en.wikipedia.org/wiki/Convention_(norm) ) The pastime of recreational knitting results in some knitters acquiring higher status. This has significant value in their circles.
One of the social conventions and contracts of modern recreational knitting is that it uses hand-held needles. The use of other technologies would allow production of high quality knit objects with lower effort, and thereby diminish the status of recreational knitters who produced their objects using only hand held needles. The use of other technologies is thus not allowed except in the past, in far away places, and behind the closed doors of commercial establishments. Breaching this convention against such other technologies is met with shunning. Advocating that others also breach this convention is met with the full spectrum of social enforcement mechanisms. People with high status, tend to vigorously defend that status.
Mary Thomas writing in the 1930s consigned knitting sheaths to museums, even though she knew that knitting sheaths were still being used professionally because they allowed faster knitting of finer and more uniform fabrics. Rutt interviewed elderly knitters that had swaved in the 1930s, but he made no effort to preserve the technology. Thomas and Rutt were recreational knitters, and they conformed to the social conventions of the pastime even as they discussed other hand knitting technologies. Gladys Thompson used a knitting sheath, but does not mention that fact in her book, Patterns for Guernseys, Jerseys & Arans. Nor does Elizabeth Zimmerman mention the fact in her 1971 Note for American Knitters, where she does talk about long needles. This was dishonest in the extreme. Only in the context of knitting sheaths is Patterns for Guernseys, Jerseys & Arans a useful book on knitting.
Thus, recreational knitters made no effort to preserve the knitting technologies that use a knitting sheath. These were not mythical or magically ways to knit; they were real world textile production technologies in use by professionals. We know something of what they were, and we know something of what they were not. From that information the technologies can be reverse engineered. Come on, this is knitting, it is not rocket science.
Anybody that needs to knit a large number of objects quickly, discovers that with hand held needles, the knitter's hands get tired and their wrists get sore. Eventually the other end of the working needle gets wedged in the thigh crease or tucked into the arm pit. More advanced are pads of straw and feathers as discussed in Mary Thomas. However, professional knitters need better tools, and leather pouches stuffed with horse hair are much better than pads of straw and feathers. However, Mary Thomas gives straw pads and Shetland knitting pouches each a single paragraph suggesting that they are equally valuable to the modern knitter. In this, she dismisses both, and I at least did not find her instructions for using either a knitting sheath or knitting pouch to be useful. Certainly her illustrations of how to knit are for a Weldon style of needle management. This is not fair to the reader that needs to knit a large number of objects quickly and picks up MT hoping for hints on how it can be done. One might use Weldon for test knitting a pattern, but a professional knitter with an order for 6 dozen pairs of hose did not to use Weldon.
MT gives knitting sheaths 3 paragraphs of their own, but there is no hint in MT that knitting sheaths in fact support 3 very different knitting technologies; one based on the pitch/yaw of a stiff needle, one based on needle flex and spring, and one based on the rotation of a curved needle. Thomas, Rutt, and even Brears display an astonishing lack of interest in the functional details of how knitting sheaths were used. The only explanation is that they considered all use of knitting sheaths and knitting pouches to be outside the social conventions of modern recreational knitting.
I am not a recreational knitter. Some days, I am a researcher. Some days, I am a textile artist. Some days, I am a subsistence knitter. And, some days, I am a professional knitter. I am not constrained by the social conventions of knitting as a pastime. Therefore, I am free to knit with any technology necessary to produce the fabrics that I want at the rate that I need. I am willing to talk over the heads of all the modern recreational knitters to other researchers, artists, subsistence knitters and professional knitters. I want others to be able to knit better, and knit faster. I want others to know that there are a variety of hand knitting technologies.
One of those knitting technologies is based on the "roll" (rotation) of a short, stiff, curved, blunt knitting needle with the axis of the roll fixed by one end of the needle inserted into the bore of a knitting sheath. A short forward stroke followed by a back stroke comprises the knitting technique that I call "swaving". Details of needle and knitting sheath design and materials make the technology more functional, but do not change the name. However, as I review the account of the invention of the knitting frame and the resulting mechanics of frame knitting, it is likely that it was based on a knitting motion resulting from the rotation of curved needles. Thus, circa 1590, what I call swaving was likely also known as "knitting".
As S. M. McGee-Russell told us on the first day of class, "Everything has a proper name. Use it! If you find something without a proper name; name it, and write a paper." If you go for a walk, you are likely to see plants and critters. Most have species names, but finding those species names may take some work and require specialized knowledge. Knitting by rotating the working needle has a name, and knitters that know their craft can figure it out. The knitters that only knit as a social pastime are unwilling to say what swaving was, and what swaving was not. They want swaving to be something very vague, that cannot occur today. This is logically equivalent to asserting that swaving (was) a mystical, magical activity.