The Knitting Fiend

There we have it, the left over ball of yarn. Some will recall my New Year’s resolution is to develop a theory of yarn use to minimize left over yarn.

Less geeky people would just refer to some sort of chart like this one: Elizabeth’s Yarn Chart.

Unfortunately, I looked at it, and I’m still unsure. After all, when I was pondering my vest, I knew I was going to make “a vest” and it would “fit me”. I knit my swatch and got a gauge of about 3 1/4 st/inch. I intended to make a vest which measured 38″ across the chest. (I’ll admit it, it came out to 39″ when I finished.)

Let’s look at what Elizabeth’s chart suggests for vests knit in stockinette using extra bulky yarn (3 to 3 1/2 st/inch) :

• Chest=36″ woud require 450 yards. (For my yarn, this would have been 3.3 skeins.)
• Chest=40″woud require 550 yds (This would have used 4.1 skeins.)

But, the page doesn’t give me a clue about the “average” vest style. Is it longish? Shortish? V-neck (which uses less yarn?) Turtleneck? (Which uses more.) Dropped shoulders? Cut in shoulders? Given all this uncertainty, if I hadn’t been using stash yarn, I would have felt I needed to buy 5 skeins “to be safe”. After all, that 0.1 skeins still needs to come out of a new skein. Plus, I need to knit the swatch, right?

I had 4 skeins. Period. I had to knit this or waste it. So, I decided “What the heck?”; I just cast on and knit. Lucky for me, I didn’t run out of yarn; the vest used exactly 3 skeins. That’s 372 meters, or 406 yds. Less than suggested by Elizabeth’s chart.

Now think about this: if I’d used the chart, and bought 5 skeins, to “feel safe”, I’d have two skeins left over when I only needed 3. That’s 67% too much yarn. Pretty yarn can be expensive. If I didn’t have to by 67% extra yarn, I could spend on luxury yarn instead of “el cheapo”!

My thrift forces me to work on this theory!

But to make a short story long: I don’t want to knock Elizabeth’s page. It overestimates a bit, but that’s better than underestimating. Moreover, her chart does provide me an estimate I can understand and turn into a number of skeins. To read advice I find useless, visit About.com edited by Barbara Beiter. I read her advice and think: “Uhmm.. yeah… I guess if I just had access to that simple chart on that daily calendar in Barbara’s purse, and were knitting items similar to those Barbara has knitted, I’d be ok. right?”

But, the best all time estimating method is found at The Yarn Harlot. On Sept. 29, 2004 Crystal comments:

you know what i do to estimate yarn? i put it all close together and try to imagine if thats the size the sweater would be if it were folded up. this works great for hats and scarves… i’m still a little touch and go with estimating sweaters this way. meh. i’m lazy with it, and have no good excuse.

Clearly, Crystal does not have my geek tendencies. Now, back to the geeky theory stuff. I can’t tell how much yarn to buy either in advance. Right now, my full generators force you to knit a swatch then either weigh it or unravel it. The problem is: You have to buy a skein of yarn first. Imperfect, right? (It is a useful method for people with loads of stash yarn though.)

Anyway, there are other web page that provide more concrete suggestions than About.com or Crystal. This one seems potentially useful for designers: How much yarn? But, is it right? It’s not worth coding unless I’m confident it’s correct. Frustrating!

I need to have a theory that I can test against actual data. It needs to be a mathematical theory, so I can code it. So, I’m going out on a limb. Here’s my untested theory. I will call it “The Let’s Pretend Stitches Are Overlapping Circles” theory of yarn usage:

• Define the “normalize stitch diameter” as equal to the square root of the sum of the squares of the inverse stitch gauge and inverse row gauge. Got that? (I’m not going to write the formula which would clarify for geeks who probably already get what I said anyway. The other people don’t care about the formula; they just want me to code it if it turns out to work! )
• Assume length of yarn per stitch knit is proportional to the product of PI and the normalized stitch diameter. (The PI is “stitches are circles” part of the theory. I anticipate a fudge factor between 0.5 and 2– which should the same for all yarns. Data will reveal the magnitude of this factor.)
• To find the total length required, multiply the length of yarn per stitch knit by the total number of stitches in the pattern.

I’m determined to test this theory, and I’m hoping a few people who knit my stuff will help me collect data. If you visit the mirror vest page, and scroll down to the bottom, you’ll see I coded to tell you “the normalized stitch diameter” and “the total number of stitches knit”. I’m planning to add these values to all future generators for items knit primarily in stockinette.

I’m hoping users who knit items, (that means you), will email me the data at the bottom. I’ll also collect my own. As I collect data, I will compare it to the theory. I’ll publish that (and we can all either have a good laugh, or be awestruck by the brillance of the “circles” theory.)

Here is the first data point. It’s data from my vest:

• Normalized stitch diameter: 0.308 inches.
• Inches of yarn used per stitch: 1.17 inches.
• Ratio: 1.17/ 0.308 = 3.18. (The “The Stitches are Circles Theory of Knitting” predicts the ratio is equal to PI, or 3.14159.)

Not too bad for a likely lame an entirely untested theory. The question is: Will the theory hold up when I knit a sweater in another gauge? When I collect more data, I’m also going to comment on the accuracy of various web pages describing ways to estimate yarn requirements.

Help me with this project. Send me data!