A good while ago, I posted about the time I needed to ply close to 600 m of yarn on my old, small foot-driven spinning wheel.
That little wheel, bought during my teenage years, was sold to me as a young girl's spinning wheel. I learned how to use it, I learned a lot about wheels on and through it, I dragged it around and I spun and spun. But it's a small wheel with, accordingly, a rather slow spinning ratio. And with the years, I wanted to spin more strongly twisted yarns, and thin very high-twist yarns, and do so faster than the little wheel would allow me to, even when treadling very fast.
So I started to keep my eyes peeled for a production wheel, and finally decided to buy a double-drive wheel, second-hand, from a Finnish producer who had long gone out of business. And this weekend, I started tuning it - replacing the whorl with a new, much smaller one (thus upping the ratio from drive wheel to whorl) and glueing additional discs to the spool to bring that ratio up too and really close to the whorl ratio. (Really close, in my case, meaning nominally1:1 for the bigger of the new discs and almost 1:1 for the smaller one.) The fastest setting needs a little more running in, or a little more tweaking, but it does work already, and the slower setting works really nicely already and will yield a spinning output of high-twist yarn, my usual thickness, of about 120 m/hour according to my first tests. Spinning output, that is, not plying output. And I am planning on doing those speed tests... soon.