Knitting Math Part 2

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SERIOUS KNITTING MATH AHEAD

The last time we talked about knitting math, I covered how to calculate proper yardage for a project. That information can be used to design a new pattern or change a current pattern into a different gauge.

The next step involves plotting the gauge to full scale. Converting an existing pattern will give you exact cast-on, decreases and bind-off stitches to match your new gauge.

(yarn shots thrown in to help you deal with the math overload)

The simplest part of this takes some measuring or pattern checking. For instance, if you have a sweater where the front is 20 inch wide by 22 inches long. Your gauge measures at 4 stitches to the inch and 3 rows to the inch, then the math would look like this:

20 x 4 = 80 stitches to cast-on

22 x 3 = 66 rows will result in proper height.

Most of the time when a pattern tells you to knit until piece measures so many inches, I don't convert that section. You'll just knit to that length whether it's for armholes or necklines.



The trickier part of pattern conversions comes when you have decreases over a defined area. For example on sleeve cap shaping. If the pattern reads decrease at edge 1 stitch every other row. This will have to be examined to your new gauge and as I had to do this just recently I will give you the sample I worked on...

Original pattern calls for this cap sleeve shaping:
BO 5 st at the begin of next 2 rows (50 st remain)
DEC 1 st at each end of every needle every other row 4 times,
Then every row 14 times
BO 14 remaining st

The Shaping of Cap on Sleeves:
Pattern schematic has the width at 17 inch at the point where the shaping begins. Shaping of cap will happen over 7.5 inches ending with a width of 4 inches to bind-off. From the above description of the original shaping we see that the first BO action is dramatic. This quick BO will create a notch on both sides which should match the bind-off for the armholes.

We then have more decreases, but at a slower pace. A total of 8 stitches decreased every other row. You'll need to look for the row gauge of the original, which is 13 rows = 3 inch (or 3.25 rows per inch). Decreasing happens over 8 rows (every other row [2] x 4 dec)... then we calculate over the row gauge (8 rows ÷ 3.25 per inch = 2.46 in). This tells us that the slower pace decrease happen over a 2.46 inch span.

We'll then match this with our row gauge... 13 rows = 3.75 in (or 3.5 rows per inch) – please note I round up when I need to. We take this number (3.5) and find how many rows we'll need to do the slower decreases.

3.5 rows per inch x 2.46 inch = 8.61 rows

This shows not much of a change or difference between the original row gauge and new row gauge. Yet my stitch count is greater and I have to decrease significantly over a shorter distance.

The remaining 5 inches would have to accommodate a larger decrease amount compared to the original gauge. Instead I take a look at an overall decrease of the full sleeve. If I calculate so see how many times per row I would need to decrease my stitch count from 70 stitches to 20 over the full cap... 50 stitches ÷ 2 (for each edge of cap) = 25. Then divide that times our row gauge: 25 ÷ 3.5 = 7.14 inches. That puts us closer to the length of cap shaping we need verses planning out each row of decrease.

To make up for the .35 remaining I'll do a non-decrease row in the beginning which will give us plenty of length on the cap.



My pattern conversion:
BO 6 st at the begin of next 2 rows (70 st remain)
K 2 row in pattern. Ending on WS row.
DEC 1 st at each end of every needle until 20 stitches remain
BO 20 remaining st



Pattern converting can become a challenge. If you break it down section by section and have your calculator, pencil and paper handy it can work out just fine. Always take notes and jot numbers down. It's a process and if you need a break, take one.

Just knowing that it is possible to end up with a garment worth knitting is huge to me. I'm sure most people would say it's just not worth it. That is totally fine too. I would rather know that it's possible then to feel like there is nothing I can do about it.

Something Different

If your reading this off of Bloglines or a Google Reader... you might want to click over just to take a gander.

Upon turning another blog-year older and having my b-day on Sunday, I wanted something new and fresh for the blog. I've been working on getting this together for months now and I don't think I'm done just yet.

Still trying to figure this whole html crap out, but I'm digging the new look.

How was everyone's weekend? Mine was wet. soaked. drizzly. The only good thing is that we didn't get any water damage. Friday started out fabulous at Nana’s Knitting Shop's Open House with my three favorite F's... food, friends and fiber! I was completely thrown off by winning a raffle prize. I never win!!

In fact enough yarn for a whole sweater!! How fabulous! and a perfect way to start my birthday weekend. Saturday lead to an afternoon at the DMV because my licence was almost expired. It wasn't half bad sitting and knitting while waiting for my number to be called. I love how knitting makes things not so painful;)

Sunday was pretty lazy with a matinee of Babylon AD. The movie was choppy and could have given more background information. It kind of left me thinking I was missing something, but lets get serious. I didn't go to see an award winning show...it's all about Vinny!! yum

Even though I started writing this on Sunday night...Tuesday has got to be the worst. I wont get into it just yet as I haven't even made it through to the end. So, I'm passing out kisses and cookies for everyone;)

A Winner

I first what to express many thanks to everyone who participated in the contest. Love the blog listings and my Bloglines has grown because of it.

I was also so amazed to see that in the middle of everyone sending me cool blogs I had been given an award by A:). [blush] awwww, thanks.



The rules seem to be as follows:
1. Post the award on your blog.
2. Ad a link to the person who gave you the award
3. Nominate at least 4 others
4. Leave a comment on their blog so they can pass it on

Now... coming up with blogs that haven't already received this award is tricky but I'll give it a go.

Tales from the Den of Chaos is a funny, witty and makes me feel like I'm not the only one in this crazy world.

So, the thing is...blog is a new great find and felt instantly connected to her new relocation to a new state.

Adventures of Old Bean is a spinner and knitter and how can you not love gratuitous baby photos.

RoseLea Spins a Yarn is spinning and knitting all the way from New Zealand.

Now for what you've all been waiting for. Hubby picked the Winner of the contest out of the hat.



And without further ado....the winner is ikkinlala!

Congratulations and thanks again to everyone for playing along.

Progress on Ogee

The front of the Ogee Tunic is off the needles.

I've done some major modifications. When reading the pattern it tells you to start the neck shaping when the slit finally measures 9.25 inches. What? So, I go looking through Ravelry and I see all the projects have very low dipping slits. I really didn't want this... it would mean I would have to wear something under it. Needless to say my slit is not that deep.

Now I have concerns about the sleeves matching up with the armholes. I will have to make some adjustments I'm sure. I have been taking notes, so if I cross my fingers everything will work out fine.

Yay Me!
It's My Blogiversary today and if you post a comment containing 3 unique blogs you'll be in for a chance to win sock yarn! Deadline is midnight tonight!! I'm hoping to draw winners over the weekend. Thank you all for everyone's list of blog entries... have been discovering new ones and loving it!

Knitting Math

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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.