Let's do the twist! Like we... oh, sorry. Gets stuck in my head.
the drop spindle. But I recently got to the point where I am finally feeling pretty good about the yarn I produce. Out of many problems I was having, it turns out that several of them could be solved by adding more twist.
In fact, "add more twist" is apparently an all-purpose fix-it for hand spinning with a drop spindle. This is NOT the case when you are spinning with a wheel, because it is much easier to over-twist on a spinning wheel. But with a drop spindle, you can go a long way before you really get over-spun.
What throws off newbies like myself is, a lot of the spin gets lost in the process of A) letting your singles rest before you ply them, B) the plying process, and C) the final wash and soak (however you perform this procedure). In other words, if you create singles that look really tight and over-spun, they will probably relax into something more reasonable by the time you are finished.
Part of the learning curve with using a drop spindle is getting a feel for this process. It reminds me of when I first started knitting things that I wanted to felt. When you're knitting this GIANT slipper, it's hard to believe it will ever be normal! But as soon as it felts, you lose all that extra height and width, and you end up with a slipper that will fit a human foot. It's kind of the same with twist in yarn.
The question is, how much is too much twist, when you are hand-spinning with a drop spindle? One answer comes when your yarn snaps and the spindle drops. That's a sure sign that you have added too much twist. (Or more likely, that your yarn is uneven and the twist "piled up" at the thinnest part, as it tends to do.)
Another sign that you have too much twist is when the single starts to double-twist, or to leap up into those little twisty loops. If you have ever created cord, you know what happens when you keep twisting a string: it double-twists, which takes the twisted cord and wraps it into a mega-twisted cord. I can see this happening with my singles, if I look closely enough. That's when I back off just a little bit.
Not happy with your drop spindle results? Add more twist next time (when you spin or ply, or both) and see what you think!