Thursday, June 14, 2012

Lost in TPI land

Followers of this blog may wonder where I have been for the past month. Well, I have been in TPI land, or TPI hell which is more accurate. TPI=Twist per Inch. 
The assignment: spin 10 yards of yarn at 1 twist per inch. Sounds easy right. HA! Sounds simple. Deceptively simple. Deviously straight forward. Wrong! Anything but! At 1 TPI (count the bumps along the edge of a yarn in a one inch length and divide by the number of singles making the yarn - more on this frustrating formula later) most yarns tend to fall apart. It requires a very grabby fibre but after a few frustrating failed attempts I dug out my shetland roving bought at THE Jamieson's in the Orkney Islands. Sigh, such beautiful special fibre and it seemed a waste to just throw a lot of it away in attempting this sample. But after a while I was able to do it. On to the next assignment: spin ten yards at 2 TPI. A few attempts to achieve precisely (well, I have the marker doesn't look too closely) 2TPI and on the the next assignment. Spin 4TPI. Then 8TPI, 12 and 15 TPI.  
Somewhere between 8 and 12 TPI I realized I did not know how to count TPI. Seems silly, given my formula above but when your attempts to achieve these assignments, especially the higher TPIs do not work, then you start to question everything. Ergo: how do you count bumps? Just the bumps on one side of the yarn, or both sides of the yarn. One side it turns out is correct. But then somewhere between 12 and 15 TPI I forgot to divide by the number of plies. It seemed impossible to spin at 30 bumps per inch but 15 bumps more doable. At this pint I was producing unusable yarn with so much twist one couldn't use it for anything but a rats nest. Hence I was questioning all the instructions. They didn't work.
Then there are the questionable formulas to figure out how much twist to put into each single (this involves length of draft or fibre between you and the wheel, your wheel ratio (how many twists each time the wheel goes around) and how many times you let the wheel turn per draft. I double checked the formulas, yes, they were correct. Then how come my yarn turns into a hopelessly tangled twisted knot? This went on for, I am ashamed to admit this, but 3 months of cursing and spinning junk! So that is where I have been. TPI hell.
The solution turned out to be all in the fibre. Selecting the right fibres for the job was critical. Spinning to the crimp (think curls, waves, in a fibre) worked for the medium TPIs but at the extreme end, one needed to think and select carefully. Silk, for example is much easier to spin at 15 TPI than wool. Take my word for it.