Thursday, September 11, 2008

Knitting Math

* * * * * * W A R N I N G * * * * * *

SERIOUS KNITTING MATH AHEAD

TURN BACK NOW

[mic: tap. tap.] Are you still with me? Okay then, you asked for it.

I've always been good at math and geometry. I get the concepts, shapes and love that everything fits perfect. Where as the English language has always stumped me. I remember having an intense discussion in the 3rd grade with my teacher about the word knife, but I digress.

So it all started a long long time ago with a project that screamed KNIT ME! The New Pea Coat from Interweave Magazine Fall 08. The pattern calls for two yarns to be knit with each other in this woven stitch pattern. Fabulous for the fall. After looking at some yarn choices I decided that a bulky weight yarn could substitute for the pattern.



Yarn: Debbie Bliss Donegal Tweed Chuncky

I swatched on 10.5's, 11's and 13's... and I suppose if I was actually doing the woven stitch pattern correctly I would have gotten a more accurate stitch count. Either way my gauge was off and not by one stitch. It was off by a lot.

Still my vision of doing the coat was not diminished. Having the coat knit up with this yarn presented some issues. First off is having enough yarn to complete the project and second figuring out new measurements for all the components.

For the time being we'll stick with the first task of yardage.

What you'll need to start with is producing a gauge swatch. You might need to do several and you'll always want to wash/block your swatch. Chose the swatch you most desire your finished texture to resemble. That is if you prefer a dense fabric or something more lofty then this is where you'll make those decisions.

With your swatch done you'll need to measure the width and height. Say for this demo we've produced a 4 x 4 inch square swatch. Take note of the stitch count and row count of the swatch. Measure several random areas to get an average.

What you've just done is produced a 8 square inch area of your future project. If your swatch was 3.5 x 3.5 then you get a 7 square inch area. Nothing more then multiplying the two together, kinda like finding the square foot of a room.

I then take a clasp stitch markers and place one at the beginning of the cast-on row through the tail by splitting the yarn. This marks the beginning of the work. I then place another one at the end of the bind-off row splitting the tail again. These markers now represent the length and yardage of yarn used to produce a 4 x 4 inch square.

Are you with me so far? Need a break... here:



Having marked the swatch from end to end you'll then need to unravel the swatch. With your swatch all undone you'll then measure the length between both markers. There are 36 inches in a yard. I started with a tape measure on the floor and measured out 36 inches sections wrapping the yarn back and forth until you've come the end stitch marker. Count the number of lengths the yarn traveled and you'll have the number of yards used to knit your swatch. If you end up an uneven amount... don't worry. You can always round up or just count it as a fraction (.25, .5, .75). For this demo we'll say we ended up with 10 yards.

The next part deals with finding the full square inch area of the project at hand. It will be helpful if there is a diagram labeling the dimensions of the piece. For this demo we'll say it's a sweater. This sweaters finished measurements are labeled (backs and fronts are separate) at 20 inches for the width and 22 inches for the length. Sleeves are labeled at 12 inch at wrist with a length at 19 inches.

You might start to wonder about increase or decreases interfering with your measurements. There is about a 10 percent margin that you need to take into consideration when making your final yardage decision. If your project has a lot of shaping and your concerned... take the widest measurement as your base and you wont have to worry about being off.

With the numbers above you'll need to multiply the widths times the lengths. Like this:

Back: 20 x 22 = 440
Front: 20 x 22 = 440
Right Sleeve: 12 x 19 = 228
Left Sleeve: 12 x 19 = 228


Added all up: 1,336

You will then take this number and divide it by the square inch area from your swatch and you have this:

1,336 ÷ 8 = 167

You then multiply this times the number of yards found in your swatch and you have this:

167 x 10 = 1,670 yards

This is the total yardage needed to complete the project at the gauge you've chosen and if your skein is labeled at 110 yards per ball then you'll need 16 skeins for the project.

Not only does this knitting math help in re-gauging an existing pattern, but helps a lot for design knitting. The down side is this is just the beginning of converting a pattern to a different gauge. Part two entails changing the numbers in the pattern to fit the changed stitch count. For example the cast-on, decreases and bind-off will all have to be adjusted. sigh. I hope I haven't scared you off but perhaps enlightened you.

If this has at all helped or you'd like more on this topic please leave a comment and I'll see what I can do.

3 comments:

A :-) said...

Geez. I was SO behind the door when they were passing out the math stuff . . . :-D Hey - check my blog, you've been nominated!

Laurelena said...

I, for one, loved the math! And I learned a new things too, about measuring the yarn for a swatch to figure out total yardage. It's so obvious, and it makes me feel dumb for not having realized that I could do that myself, but thanks a lot, Kris! :D

Jinky said...

thank you make it easier for me to understand how to get the yardage...
now next... :) excited to read lesson 2.. I hope there'll be more...