Sunday, June 17, 2007

Measuring Wraps Per Inch (WPI)

By Leigh

Tina and Sharon were interested in my comment in my last post about how I use wraps per inch (WPI) in spinning. Of course this got the wheels turning and before I knew it I had another topic to post about!

Measuring WPI is actually quite easy and extremely useful. One thing it does is help ensure your yarn is a consistent size throughout the entire bobbin. By periodically checking your WPI, you can adjust your spinning to keep it consistent. Knowing your WPI is also invaluable when planning for some projects, such as an item knitted from a commercial knitting pattern. The pattern will require a specific size of yarn, so you have two options. You can either spin as you will and then change the pattern to accommodate your yarn, or you can spin the size yarn called for in the pattern.

The only tool that is required is something that can measure an inch. It can be a boughten tool like this one .......

Purchased WPI counter.
... but actually a simple ruler will do. The one I like the best (when I can keep track of it) is the one I made from the instructions on Patsy Zawistoski's wonderful video, Spinning Wool - Basics and Beyond. I learned how to spin from this video, so I can't recommend it highly enough!

Homemade WPI counter.
My favorite counter is simply an 8 inch length of quarter inch dowel, marked in inches, and with a notch cut into one end.

The secret to an accurate count is to neither add nor subtract twist from whatever you are measuring. It is probably easiest to understand this with a little experiment:

Take about a yard of 1/4 inch ribbon and wind it around a stick, ruler, or whatever. Notice that the ribbon takes on twist as you wrap it. OK. Unwind that and now try putting the ribbon onto the stick by rolling the stick. You will find that you can roll it onto the stick smoothly.

Measuring WPI of Shetland singles
I secure the end of my yarn in the notch and begin to roll the stick toward me. I either loosen the brake band (on Scotch tension) or remove the drive band from the bobbin (on double drive) so that the yarn is easier to pull off the bobbin.

My marks are only on one side of my stick, so I keep track of my count by watching for that mark each time it comes around. I use my right hand to roll the stick toward me, and my left thumbnail to guide the yarn into place. The stick should be solidly covered with yarn. When I get to the next mark, I write that number down, usually on a note card to which I also attach a sample of my single and a sample of the yarn plyed back on itself. My card can also contain other information I want to remember such as fiber type and source, spinning ratio, etc.

When I'm finished counting, I secure my brake or drive band again and unroll the yarn back onto the bobbin as I treadle.

I already gave you a link to a chart which gives WPI for standard commercial yarn sizes, but then there is the question, what size do the singles need to be spun? Here is a rough guide to use as a starting point, using the same yarns as are mentioned in that chart:

For a 2-ply measuring 18 WPI, spin your singles to about 34 WPI
For a 2-ply measuring 16 WPI, spin your singles to about 27
For a 2-ply measuring 14 WPI, spin your singles to about 25 I
For a 2-ply measuring 12 WPI, spin your singles to about 22
For a 2-ply measuring 10 WPI, spin your singles to about 17
For a 2-ply measuring 8 WPI, spin your s ingl es to about 13

Even so, remember the famous adage to "Sample, sample, sample." It's especially important to wash a length of the sample, as washing will bring out a yarn's loft and effect the resulting size. And it would probably be a good idea to attach this to the sample card as well.

I keep my sample card close by and use it to monitor my spinning by comparing it to the sample on the card. By trying to match the two, I can keep pretty close to my desired size. I only use the counter occasionally, usually when I sit down to spin and perhaps one or two other times during that session. This method has really helped me gain consistency with my yarns and I would recommend it to anyone.


Anonymous said...

Great post! Very informative. There is a knit designer who instead of yarn type gives wraps per inch. I find this more helpful, also.

Julie said...

I've been wondering how best to use that gadget!

Cathy said...

Thanks for the tips on measuring WPI Leigh! It's not something I've had occasion to do yet, but I can see where it would be very useful. If you're measuring a lofty yarn with some stretch (like commercial worsted) do you pull the yarn taut? Or is that not a situation that would ever arise with handspun?

Teyani said...

thanks for the measuring tips - what great information!

Leigh said...

Thank you all! I'm delighted to offer some useful information.

Cathy, I would measure WPI for a lofty or elastic yarn by wrapping gently and not stretching it out. The resting size is what I'll be working with and this is also the size the yarn will be in the finished item after washing.

Kathy said...

Before I was so technically advanced as to have an actual "stick" to use, I would use the second joint below the fingernail on my index finger as it's usually about an inch between joints in that spot. And I never lost or misplaced it.
But that was in the Dark Ages, you know...and the technology of using an actually marked stick intrigues me.

(I have used a device similar to the first photo, Leigh. But I remember being about the first one I knew who actually paid good money for it. I knew others in my midwestern guild would have laughed at anyone being silly enough to pay good money for a "device" like that!) LOL But, come to think of it...I was the only one who could be precise with my guage. Imagine that. ;)

Leigh said...

Kathy, you know how to make me smile! Very clever to use your own finger to measure WPI!

My MIL bought me the fancy 'stick' in the first photo. It looks nice hanging on my spinning wheel, but to be honest, I like my little dowel rod better.

Jackie said...

Thanks for the useful information! I am learning so much about spinning. Now all I have to do get my yarn consistent and I will be all set!

Cloudy Stitches said...

I love all this info thanks I don't spin but my ma used to Amanda

Leigh said...

Thank you! Glad to be of use. :)

Janet said...

Thanks for the information. I have been searching the internet for information for the technicalities of spinning. Very helpful!