Plying Twist

One of the things I refer people to most often is the piece that I wrote about plying twist. (Not read it yet? You can find it here, go read it and then head back to this post).
Plying twist gets much easier to judge as you become a more experienced spinner. In general, most people don't use enough plying twist. When I first learnt to spin I was taught how to do a ply back test. The one where you take a length of singles and let them twist back on themselves, then use that to judge your plying twist. What I failed to pick up on was that you have to do that test with freshly spun singles. Even singles that have sat on a bobbin for a couple of hours won't give you an accurate measure of plying twist.

Some of my first "proper" skeins... the singles were pretty good, but the plying job was just plain shoddy!
However, I knitted with it and was pretty happy with the finished shawl.

​So with that in mind, just how important is plying twist in a finished fabric....

The Underplayed fabric is actually really nice, it has a nice feel to it, doesn't really suffer from biasing, if I hadn't labelled carefully I would be hard pressed to tell the difference between that and the one with a balanced ply. 
The singles I used were actually from the same bobbin I used for the singles swatch in the last blog post.
The only disadvantage will be long term, the lack of plying twist means the ends of the fibres aren't as tucked in to the yarn. Over time it will be more prone to pilling, and won't wear as well.
The over-plyed swatch however has the opposite problem of the swatch made from singles, it skews, though this time in the opposite direction. It also feels harsher, stiffer, and just not as nice. I bet it will wear very well though...

Here's a close up of the skeins, left is under-plyed, centre is balanced, right is over-plyed.

How do you make sure you get it right? 
When you're spinning pull off a small section of singles. Break the singles being sure not to let any twist escape. Fold it in half, then let the single wrap around itself. Tie a knot in the end and put it in a safe place! 
When you start plying find your sample, and use that to judge the plying twist. Be sure to take a look at the yarn after it goes on to the bobbin as sometimes the stuff by your hands is ok, but as it winds on you can alter twist slightly.