Grading for larger sizes: adjusting for shoulders 101

A few months ago I decided to grade Lorraine’s Lace for a larger range of sizes. The original version of the pattern included instructions for the CYC XS - XL sizes, which range from a 71 - 117cm (28 - 46”) bust size. I wanted to add in the rest of the CYC sizes (2X - 5X), which would then go all the way up to a 158cm (62”) bust.

I thought it would be simple enough. I already had a spreadsheet set up from my first iteration of the top, so I added in the measurements for the larger sizes, let the spreadsheet calculate all the stitch and row counts for me, then made a new copy of the pattern with the larger sizes in it. I hadn’t gotten proper feedback for the XL size in the pattern test for the original top so I found testers for the XL to 5X sizes and sent it off - easy enough, right?

Well, no. Most of my testers were finding it hard to get yarn thanks to the pandemic, but one of my XL testers was able to get hers and finished the top in almost record speed. She was very happy with her top but when I got the pictures, I started worrying. Here are side by side pictures of my original top (in a size S) and Carolyn’s top (in the XL):

At its core the original version of Lorraine’s Lace is a very simple top - ignoring the lace panel at the back, it’s a stockinette top with no shaping. You simply cast on enough stitches for your bust size, knit a tube up to your underarms, work half the stitches flat for the front and half the stitches flat for the back, then join for the shoulders. It’s a bit easier to see how it’s constructed with the schematic:

In a shirt like this, the outer edges of the front and back panels are supposed to hit on the shoulder joint. It’s essentially a sleeveless top. (Lorraine’s Lace gets its very short sleeves by picking up around the armholes and knitting sleeves on.)

Let me say that again - the outer edges of the stockinette part are meant to hit your shoulder joint. Take a look at Carolyn’s top - the stockinette edges are pretty far down her arms. What was going on? I went back to my spreadsheet and took a look at the width of the shoulders (measurement C in the schematic). In the S size, the shoulders were 10 stitches wide, which translates to 5.8cm when knit at the correct gauge. But in the size XL, the shoulders were 19 stitches wide, or 11.3cm - almost double the width, which explains Carolyn’s picture. Really panicking at this point, I took a look at the 5XL size - the shoulders were 33 stitches wide, which was a whopping 19.7cm. I emailed all my testers and asked them to pause for a while while I figured it out.

I started out by taking a look at the measurements I was using. Lets look at the bust and shoulder widths recommended by the CYC for the S, XL and 5X sizes:

Size	Bust circumference	Cross shoulder width
S	33"	14.5"
XL	43"	17.5"
XL	61"	18.5"

It took me a while to see it, but the reason that the shoulders were so wide was down to the fact that the ratio between the bust size and the shoulder width changes dramatically as the sizes get bigger. Let’s throw a few extra columns into the table:

Size	Bust circumference	Shirt width (half bust circumference)	Cross shoulder width	Shirt width:shoulder width
S	33"	16.5"	14.5"	1:0.87
XL	43"	21.5"	17.5"	1:0.81
XL	61"	30.5"	18.5"	1:0.60

What does this mean? Take a look at the size small. If you compare the shirt width to the shoulder width, they’re relatively similar - the shoulder width is almost 90% of the shirt width. But once you get up to the 5X, the shoulders are much much narrower than the shirt width - they’re only 60% as wide as the half bust. For my visually-minded friends, this is what that means in practice:

In the smaller size, the widest point of the bust line (where you normally measure bust size for shirts) is almost directly under the shoulder joint. So if you just keep knitting flat, your shirt edges will hit the shoulder joint. But in the larger sizes, the outer edges of the chest hit further down your arms, where your shoulders are already starting to slope down. I’m not entirely sure what the measurements of the plus size model in the images above are (the images are based on sketches from Tracing Real Body Models), but I’d guess she’s about an XL - the difference becomes more pronounced as the sizes get bigger.

So what does this mean for shirt construction? When you construct a shirt like Lorraine’s Lace originally was, what you’re doing is creating a rectangle. Since you’re using half the bust width as the basis for the front and back sections and just knitting straight up, you’re essentially drawing a straight line up the wearer’s body from their underarms to their shoulders, which works nicely for the smaller sizes - if your shoulders are about 90% as wide as your bust width, that means you have 5% of the width hanging over each shoulder, which means you get a tiny little cap sleeve. But when you do the same process for the 5X when your shoulders are 60% of your bust width, that means you have 20% of the total width hanging off over each shoulder, which means that instead of the edges hitting your shoulder joint, they’re almost halfway down to your elbow. Here’s the schematic redrawn, with the purple line showing you where the shoulders would sit inside the shirt:

So, what’s the solution? The thing you need to work towards is making the top section of the shirt (from the underarms up) narrower than the bottom part of the shirt. In most shirts, the bottom of the underarm hits a little above the bust line, so you can safely start decreasing from the point at which you split for the underarms. If I wanted the edges of the shirt to sit exactly at the shoulder joint, I’d need to do it for all sizes - you’d definitely want to do this if you’re constructing a shirt with set-in sleeves. But given this shirt’s fit I was fine with a little drop sleeve. The way I ended up doing it was to figure out how wide I actually wanted the shirt to be for the larger sizes, then calculate what the difference was in stitches between the bust width and the shoulder width. This ranged from 6 stitches in the XL to 18 stitches in the 5X. I then added instructions to cast these stitches off over several rows at the underarm, then knit straight up from there.

The eagle-eyed among you will have noticed a second problem - if you take a look at the 5X shoulder width schematic above, you’ll notice that the neckline is also problematic. Scaled up for the larger sizes it’s almost as wide as the shoulders. Fixing that was a whole other task, which I’ll save for a separate blog post.

I was aiming here to explain the reason why you have to adjust for shoulders, but I intentionally didn’t go into a whole lot of detail on the final fix. If you want a rundown of exactly how to do all the calculations, check out Sister Mountain’s excellent post on how to set up your spreadsheet with all the formulas you need for individual pieces of the garment.