Monday, December 31, 2007

How to use a swatch to plan a project.

Thanks all for your help with justifying my yarn slip-up. I figure I'll just ignore it, I'm only human after all, and pretend it never happened. When it comes to these little addictions, we all fall off the wagon sometimes and it's best not to waste time beating yourself up about it. Rather I will use the energy I would have used beating myself up about it, and direct said energy into crocheting these little sheep.

House Guest (HG) is on her way home again. I do hope she comes back soon, I have way too much fun when she visits even if it is rather hard on my yarn fast.

I realized that I had forgotten to show HG how to use one's swatch for doing math. I'm not a big fan of swatches generally, but they can be useful from time to time. So here we go: How to use a swatch to plan a project.

First off, you need a swatch. A swatch is a small knitted sample knitted prior to the main project and used to test the yarn, the fabric, the needles and the knitter. Swatches help you to know the finished texture, drape and other important qualities of the fabric before you begin the main project (which can save you a great deal of time and energy).

Bigger is better when it comes to swatches. You can use a 1.5" wide swatch if you like, but when working on bigger projects like a sweater, you really want one somewhere over 6" wide. The bigger your swatch, the more accurate your measurements. Then again, don't go knitting sweater sized swatches every time you want to knit some socks - a little bit of common sense is also involved here.

The ideal swatch size is around 4" square for a smaller project like a hat and 6" square for a larger one like a sweater.

Another important thing to know about swatches is to knit them with the same size needles you plan to knit your project in.

Now, go knit a swatch (cast on 30 stitches or so, knit in the intended stitch pattern for lets say 30 rows and take the needles out - HG, you already have a lovely swatch which you can use). The size of your swatch depends on the size of your yarn, the size of your needles, and the individual knitter's style. And they told me size doesn't matter.

Now that you have your lovely swatch (See, mine is done in the intended colour work that will be present on the final sweater. I've also knit mine in the round as the sweater will be knitted that way and I get a more accurate reading this way.), lay it flat on a table. Take a ruler (we will use imperial measurements here as HG spends most of her time in the USA) and lay it on top of the swatch so that it lines up with one row of knitting.

Count how many stitches are in two inches.

Each stitch looks like a little "V".

It's okay to get 1/2 or even 1/4 stitch counts. What's important is that you don't ignore it as 1/4 of a stitch over two inches can mean a great difference in something as large as say, a hat. So keep it in. So for example, maybe you got 8.25 stitches per two inches, don't round down to 8. Keep it as you see it.

Do this three times at three different places around the swatch and calculate the average (first+second+third=sum. Divide sum by three and the result is your average stitch count over two inches).

So, for example, on my swatch I got 9 stitches per 2 inches on size 5.0mm needles.

There are two things to do with this number to make it usable.

First, most yarn labels and patterns list gage by 4" or 10cm, so take your stitches per 2 inches and times it by two. In my case 9x2= 18. I have 18 stitches per 4". This is most helpful if you are following a pattern as you can adjust your needle size if the number of stitches doesn't match the pattern recommendation. So if I wanted 17 stitches per 4" I would knit a new swatch with a larger needle size and play around that way until I got the number of stitches desired.

Second, and this is the most helpful step when designing a project yourself, divide your stitches per 2 inches number (in my case 9) by 2 so that you know how many stitches per one inch you have. In my case 9/2=4.5. 4.5:1" or 4.5 stitches per one inch.

My numbers so far:

4.5sts : 1"

9sts : 2"

18sts: 4"

Next we look and see how big we want the finished project to be. Now there is a great deal of literature on ease and the like, all of which effect the desired measurements in relation to the actual body size of the individual.... it's complicated. Let's ignore it as we are going to knit a hat.

My head measures 22" around, but I like tight hats, so let's say I want my hat to be 21.5" around.

So I take my stitches per one inch and I take my desired hat circumference and I multiply the two together.


This means that I should cast on 96.75 stitches if I want my hat to be the desired size.

Sounds good to me, except, I don't know how to cast on point seven five of a stitch. So I'm thinking there is still more work to be done.

Next I look at my stitch pattern. How many stitches does it take to repeat one pattern? Well the ribbing is k1, p1 ribbing, so it only takes two stitches to repeat. However, the colour work takes 6 stitches to repeat one pattern.

If I take my magic number (96.75) and round it up (97) I get an odd number, which I know doesn't work with a 1x1 ribbing (it doesn't divide into two). So let's round it down to 96 sts.

To refresh your memory, these are the numbers I have so far:

gage - 4.5sts : 1" or 18sts : 4"

Stitch patterns

ribbing - 2 stitch repeat

colour work - 6 stitch repeat

desired circumference - 21.5"

cast on number - 96sts

Now we test to see if 96 sts will actually work.

We will divide the cast on number by each stitch pattern number to see if it comes out with an even number.

96/2=48 <---happy!

96/6=16 <---also happy!

Good, it works. I can use this number to make a hat.

But what would I do if it didn't work?

Let's pretend that I have a pattern that has a repeat of 49 stitches. 96 divided by 49 does not equal an even number (96/49=1.9591). So I know that I either have to adjust the stitch pattern or adjust the number of stitches. Let's do the latter as it's much easier.

Look at the funny number I got when I divided the desired total number of stitches by 49. Take that funny number and round it to the nearest whole number (in this case 2) then take the number 49 and times it by 2. What do you get? 98. 98 is very similar to 96, so maybe I can use 98 stitches on this hat instead of 96. But let's test it.

How big would a hat, knit at this gage, be if I had 98 stitches? 98 divided by the number of stitches per one inch (98/4.5=21.777) means that my hat would be just under 22 inches around. That's well within the desired range, so I could make it work with 98 stitches.

It seems a little bit complicated at first, but it really can save quite a bit of time and frustration, especially when designing your own knitted object. Give it a try and if you have any questions or comments, drop me a line.


TinkingBell said...

Great explanation (and happy New Year) - but don't forget a sweater swatch is called (wait for it, wait for it)


A sleeve! (Hahaha)

~Tonia~ said...

Math hurts my head. ;)

Nat said...

You are absolutely amazing. :)

I certainly needed this, I had to rip out everything I knitted on the way back as it would have barely have fit me. Such is life. :) At least the design has been approved, which definitely helped my motivation to start again.