Thursday, February 21, 2008

Got Gauge?

My apologies. I was intending to have this post up a couple weeks ago. But that week, I was blind-sided by a little (understatement) unexpected stress. In order to deal with the problem responsible for aforementioned stress, everything else had to take a back seat. I think every time I've mentioned life stress on this blog, it's all been pertaining to the same situation/problem. Right now it's all coming to a head. Which is a relief because it means (hopefully) the end is near. And now that my extremely vague explanation is out of the way, let's march onward, shall we?

The following is by no means intended to be an exhaustive resource for altering the gauge of a pattern or substituting yarn. If for no other reason than, attempting to blog that would be, well, exhausting. With that said, there are many fantastic books available for those who would like to explore the topic further, some of which I will mention and/or link to.

How would you like to be able to knit any pattern in any yarn you choose? All you need are a few simple tools and some basic information.

The Tools:
  1. Your brain
  2. A calculator
  3. Paper
  4. Pen or pencil
  5. Gauge swatch of your chosen yarn, knit in the stitch pattern of the project you're wanting to make
Basic Information:
  1. The stitch and row gauge of the pattern
  2. The stitch and row gauge of the swatch you knit
* One thing to pay special attention to is the multiple that stitch patterns are worked over. You'll see what I mean in a little bit.

Now to show you what to do with those things, we're going to use a basic generic pattern as an example. This one is for a run-of-the-mill adult's winter hat with a stockinette stitch body and K1,P1 edging.

Itsa Hat Pattern

Yarn: Approximately 90 yards of bulky weight

Needles: Size 11 US 16" circular
Set of size 11 US double pointed

Gauge: 12 sts and 16 rows = 4" in stockinette stitch in the round, on 11 US needles

Finished Size: 21" circumference

- With size 11 circular, CO 64 sts and join
- Work in K1,P1 ribbing for 2"
- Rows 1 - 16: Knit even in stockinette

Beginning of decrease rows (Note: switch to DPNs when there are too few stitches for circular needle)
- Row 17: K6, K2tog. Repeat to end of round
- Row 18: K5, K2tog. Repeat to end of round
- Row 19: K4, K2tog. Repeat to end of round
- Row 20: K3, K2tog. Repeat to end of round
- Row 21: K2, K2tog. Repeat to end of round
- Row 22: K1, K2tog. Repeat to end of round
- Row 23: K2tog. Repeat to end of round

- Cut yarn, leaving an 8" tail. Thread through remaining sts, secure, and weave tail into wrong side of hat.

Now say you want to make this hat in a DK weight yarn. The first thing you need to do is knit a swatch in that DK yarn, in the stitch pattern of the hat, which happens to be stockinette. Let's imagine that you did that and your gauge was 22 sts and 30 rows = 4"
So we now know that the pattern's gauge is 3 sts per inch, and yours is 5.5 sts per inch. In order to find out how many stitches you need to cast on in order to get the same circumference as that in the pattern (21"), you need to divide your stitch gauge by their stitch gauge:
5.5 divided by 3 = 1.833333333
We're going to neaten that number up by rounding it to 1.83 . So now you know that you need to knit 1.83 stitches for every 1 stitch that was knit in the bulky weight yarn to end up with same size garment, which makes perfect sense because your yarn is thinner than the bulky.

If you look at the pattern, it tells you to cast on 64 stitches. Multiply that number by 1.83 to find out how many you need to cast on with your DK weight.
64 x 1.83 = 117.12 which you would round down to 117.
You can check your math like so: The pattern had a gauge of 3 sts per inch in bulky weight and told you to cast on 64 sts. 64 sts divided by 3 gives a width of 21.33". If you cast on 117 sts with a gauge of 5.5 sts per inch, 117 divided by 5.5 gives a width of 21.27". That's extremely close. In fact, I'd be willing to bet a pretty penny that no one is going to walk up to you and say, "That hat would look so much better on you if it were just 6/100 of an inch wider."

Now do you remember the part above where I told you to pay special attention to the multiples of stitch patterns? Well the K1,P1 ribbing edge of the hat needs to be worked over an even number of stitches. Otherwise, you'd K1,P1 across but when you got to the end, you'd K1 and there'd be no more stitches to finish with the P1. So with that in mind, we know that we need to cast on an even number of stitches, which 117 is not. At first glance you might think, "Well cast on 118 stitches and let's be on our way." But take another glance. Are there any other parts of the pattern where stitch multiples are important? See the first decrease row where it says, "Row 17: K6, K2tog. Repeat to end of round."? Think of that as a pattern worked over a multiple of 8 stitches (K6 plus the 2 you'll be knitting together.) Once again, if the number of stitches on your needles is not divisible by the multiple of 8, you'll be knitting along only to discover that you've run out of stitches at the end of the row before you were able to finish the pattern. So we know we need the closest even number to 117 that is divisible by 8, which would be 120.
Cast on your 120 stitches, and follow the patterns direction to knit 2" in K1,P1 ribbing. The next set of instructions say to knit 16 rows in stockinette, then you'll be starting the decrease rounds. But remember, your row gauge is smaller than that of the bulky weight yarn. If you only knit 16 rows, you'll have a very short and dorky hat. Instead, you need to figure out how many rows you need to knit in order to create the same length of fabric as the bulky yarn makes. And to do that, we're going to do the same thing with the row gauge as we did with the stitch gauge. Divide your row gauge by their row gauge:
7.5 divided by 4 = 1.875, which we'll round up to 1.88.
Now multiply that number by the number of rows the pattern tells you to work:
1.88 x 16 = 30.08, which we'll round down to 30.
So after your K1,P1 edging, you need to work 30 rows in stockinette before you start the decrease rows.
I told you this wasn't very hard. =) Only one more adjustment to make. You can see that there are a total of 7 decrease rows. And since you know the row gauge of the pattern (4 rows/inch), you can figure out how much length is added to the hat by those seven rows:
7 divided by 4 = 1.75"
But knitting 7 rows in your thinner yarn will only add .93" of length - 7 (the # of rows) divided by 7.5 (your row gauge) = .93. The quickest solution I see to this problem, would be to add a row in between each decrease row. So the instructions would read:

- Row 17: K6, K2tog. Repeat to end of round
- Row 18: Knit
- Row 19: K5, K2tog. Repeat to end of round
- Row 20: Knit
- Row 21: K4, K2tog. Repeat to end of round
- Row 22: Knit
- Row 23: K3, K2tog. Repeat to end of round
- Row 24: Knit
- Row 25: K2, K2tog. Repeat to end of round
- Row 26: Knit
- Row 27: K1, K2tog. Repeat to end of round
- Row 28: Knit
- Row 29: K2tog. Repeat to end of round

You're now working the decreases over a total of 13 rows. Let's check our math. 13(the # of rows) divided by 7.5 (your row gauge) = 1.73" which is very close to the 1.75" of the bulky weight hat. Yay! And now you're all done. :)

You can use that same technique to alter other patterns. One more word of advice though. When altering sweater patterns, I've found when I come to the armhole shaping, and plug this formula in, even though all the maths add up and the stitch counts are what they should be, in some instances I come across a problem. I inadvertently alter the slope of the armhole, and when it comes time to sew all the pieces together, they don't fit like they should. Obviously, the more shaped the armhole construction is, the more likely this problem will occur. For that reason, I use another set of techniques to recalculate the shaping. Like the previous technique, it may sound intimidating at first, but I swear it's not hard if you're pointed in the direction of the right resources. As this post is already long-winded, I'll end it here. But if enough of you are interested , maybe I'll elaborate on altering armhole shaping at a later date.

I leave you with a list of links to some wonderful books that are rich in easy to understand info on altering your patterns:
Sweater Design In Plain English, by Maggie Righetti
Vogue Knitting: The Ultimate Knitting Book
Stitch 'N Bitch Nation, by Debbie Stoller
Teach Yourself Visually: Knitting Design, by Sharon Turner
Designing Knitwear, by Deborah Newton


String Theory Blog said...

I'm impressed. I find myself constantly trying to get good enough at things to teach them to others (as opposed to just good enough to muddle through on one's own). I hope you teach somewhere, you seem quite talented at explaining stuff. I honestly don't think you can truly enjoy working with fibers until you can reliably switch out fibers and navigate gauge like this. Excellent post!
(Spinning is an addiction for me - that's why I only do it once a year! But you should try, it's even more fun to do a project from yarn you've spun.)

Steph said...

string theory blog,
Thank you - I'm flattered by your compliments. =) But no, I don't teach anywhere. I've considered it a time or two. But it seams to meet with the same obstacle that many of my ideas do - I don't know where I'd find the time. =(
I have NOOO trouble believing that spinning is both fun and addictive. That's what I'm afraid of.

Knitted Gems said...

Great post! Your list of books is a great reference library. The one written by Maggie is perhaps my favorite.

Hadley Gets Crafty said...

Man, you are the guage queen. I'm ashamed to say that I'm one of those rogue knitters who never even swatches... Your attention to detail is no doubt why your finished products always look so nice!

Steph said...

knitted gems,
Thanks. =) And I agree - what knitter doesn't love Maggie? I'm convinced only the ones who haven't read her books.

hadley gets crafty,
Don't be ashamed. Every knitter is entitled to do things their own way. Besides, I have a dirty little secret.....I don't ALWAYS swatch....but shhhh, don't tell. =)