Well. When I first learned of the CYC classifications, I was pleased! FINALLY, there was a way to group yarns by thickness, regardless of who made the silly things.
It isn’t at all difficult to set up a swatch ring of yarns, similar to a swatch ring of fabrics like costumers use (for color matching in the case of costumes; at least, that’s what mine was for). Purchase or scavenge from the supplies most of us have lying around either a “bone” ring or a binder ring. Bone rings are often available at Joann’s; binder rings, at Staples, Office Max, and other office-supply places. Maybe a 2"-diameter ring will do the trick; if your stash is mighty, you may want a larger ring.
Now go to your stash and create graded swatches. Clearly, you can only sample/cut what you already own, but it will be better than no guide at all.
Line up the skeins from finest to bulkiest: Laceweight (Class 0) through Chunky/Extra Bulky (Class 6). Cut the same length from each skein, say, 6" or so. Loop each one around the bone/binder ring and LABEL it with a sticky label or a tie-on label as to its weight, sts/in on #__needles/hooks, and any other info (fiber content?) you think you’ll want to know Out There.
Now you have yarns of your own to carry with you on that ring to the Famous Fiber Festival. When you find the Unlabeled Yarn, just get out your ring and see which weight the Unlabeled Yarn is closest to.
I don’t understand why this is such a big deal. What am I missing?
Well, no it’s not [I]absolutely exact[/I] but it can get you in the ballpark. [U]Then[/U] you swatch and figure out what gauge you get on what needle. After a while and with experience with yarn that are different weights you can tell, I do this with the odd balls I find at thrift stores - I can tell a worsted from a bulky from a fingering or sport. And sometimes, it doesn’t really matter just get it and knit it in your project.
I am looking of different methods. I think the Knitting Daily article does a disservice to WPI. WPI is a quick way to determine an approximate yarn size, but I was looking for alternatives.
I carry a mini Maglite with me (get caught in a strange building when the power goes out and you are thankful for that small light.)
I scribed three marks (0, 1 inch, and 2 inches). I pull it out and wrap a few inches of yarn and I have an approximate yarn size. Since it is my gauge and compared to other samples I made I have a good comparison.
I am looking of other methods.