I had been suspecting it for a while, and the last Textile Forum gave me the opportunity (and the willing participants, a big thank you to you all!) to do a little test.
If you'd like to play yourself, here is the photo of one hand-spun thread. What twist angle would you read out for this one?
Once you're finished, scroll down... and see what others measured.
Done?
Here you go:
As you can see, measurements of the eight participants of this mini-study range from between 20° and a bit to 48° and some, depending on where the measurements were taken... and who took them. Several people took measurement in a similar spot (there are two small black dots about in the middle of the thread), but even then, results range from 31° to 48°.
So. Twist angle. Hello there. It would have been nice to have a reliable, measureable something to describe threads with... right? Describing fabrics or threads with words is hard in any case, but this just seems to make it even harder.
Sigh.