06 July 2015

Wedding sweater: math(s)

Oh, mathematics. Where would a knitwear designer be without you? While it may not be the most fun for those of us who just want to knit, swatches, measurements, and calculations are vital elements to creating a sweater that fits the way we want. And if you like the fit, then you will love the sweater and wear it all the time. That's what we all want out of our craft, isn't it?

So, math(s). I found that my swatch on US4 needles gives me 6spi and 8rpi or 24 sts x 32 rows = 4", which is pretty much what I was aiming for (yay!). I'm going to create a sweater with a 38" bust, giving me 1" positive ease, which means I should cast on 228 sts (38 * 6 = 228). Since I also plan to work an integrated button band, I'm going to add six more stitches to account for the button band overlap, giving us a grand total of 234 stitches. 

It may be all banged up, but my gauge tool is one of my best friends

The original plan was for a deep, ribbed hem, with the ribbing contracting the fabric nicely to provide waist-shaping without a lot of extra work - see how the ribbing at the bottom of the swatch draws it in? (I like waist shaping, but sometimes you just want to knit a tube/rectangle without keeping track of things beyond length to underarm.) However, since the original sketch, my sister and I have mulled things over and decided to have a more standard body to the sweater, so I'm going to work a garter stitch hem. I think this will make for a sweater that is easier to wear unbuttoned. A deep ribbed hem would look cute buttoned up but may not hit exactly right with the dress, so we've decided to make that change. 

With our bust/hip number, what Elizabeth Zimmermann called "K" or the key number, we can calculate the other numbers needed for our raglan yoke. The numbers we will need include:
  • cast-on for sleeves - approx. 1/4 of stitches, though we are working 3/4 sleeves, so will start with a slightly larger number, since our cuff will begin at a wider part of the arm
  • stitches needed for upper arm circumference - approx. 1/3
  • how many stitches to be held for the underarms - 8%
  • and our neckband goal stitches or how many stitches will remain after the raglan shaping of the yoke - approx. 40%, since we have decided to make a reasonably high yoke that will then fall open nicely when buttoned up most of the way

The other important thing to determine is the buttonhole rate. We have approximately eight rows per inch on the swatch. Since I do not yet have buttons, I am not constrained in how many buttonholes I can have, but something like every two inches seems about right. To get an exact number, I do have to figure out the approximate length of the sweater from hem to neck before I begin - something that can be ignored if you knit on your button bands after knitting the sweater. ... spreadsheets ... math ... double-check ... hold measuring tape up to self and be grateful my sister and I have similar measurements ... Looks like I will be able to do ten tiny buttons up the front of the sweater - I'd better go on a button hunt before we head up to Maine!

Previous steps: 1. Yarn choice. 2. Sketching. 3. Swatches

Next step: Knit knit knit. With all the numbers in my spreadsheet, I should be able to happily knit away on this. Cross your fingers for me that I can knit like the wind. with wool. in July. Luckily, it's fingering weight, so I don't have three pounds of wool in my lap. Hopefully I will have lots of progress to show you next week.

Thanks for stopping by, and happy knitting!

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