Nothing bothers me more than sleeve/shoulder seams that do not sit precisely on the shoulder bone. Most likely, that bit of tailoring finesse harkens back to my high school, Home Ec classes. In our final year, we tailored a suit and the teacher was a stickler for proper fit. Sleeve/shoulder seams were one of her most emphasized, fit features. She taught us that the shoulder of the seam that joins the sleeve to the body must sit exactly on the shoulder bone. And so it should.
This potential, fit faux-pas only happens with garments that have set-in sleeves. Personally, set-in sleeves are not my favourite style. I think they make me look like a line backer. But from time to time, I do knit a sweater with that more tailored style. More than from time to time it seems.
The Patch Work sweater, worn yesterday.
My own design with a contiguous shoulder.
The Must Have Cardi
Graylina, knit during the 2014 Olympics
But always, I am very fussy about the shoulder fit and make adjustments to the pattern to ensure that seam falls precisely on my shoulder bone.
How do I do that? Well, first, I make sure I know my shoulder measurement. (Notice a trend here in learning how to make sure your sweater fits? Start by knowing to the partial inch what size you want to knit) In the case of the shoulder, there is no ease involved as there is in the width/circumference of the garment. Without ease, I can measure myself instead of a garment. My shoulder width, bone to bone, is 14 inches.
To account for the stretching that naturally takes place in a knitted garment, I use a slightly smaller number for the knitting of my shoulder width: 13 1/2 inches. But how wide are the shoulders in the pattern? Some patterns include a schematic or drawing with that number for easy cross referencing. But if not - back to the calculator.
Patterns with set-in sleeves will have the knitter cast off stitches at the underarm, then decrease further stitches at each armhole edge as you knit towards the shoulder. Take a look at the number of stitches remaining after the decreases. Divide that number by your gauge to determine how wide the shoulders are.
For Example. With a gauge of 5 sts per inch and 70 stitches left on the needles, the pattern in question calls for a shoulder width of 14 inches. (70 divided by 5). Since I want a 13 1/2 inch shoulder width, I need a few more decreases. In this case half an inch would be 2 1/2 more stitches. I would choose then to do either one more decrease at each armhole for a total of two - slightly less than needed - or two more decreases at each side for a total of four decreases. My choice would depend partially on the wool being used. Is it really stretchy? If so I would chose four more decreases. If not, two stitches would probably suffice. Either choice, easily done and you get a nicer fit.
Now for sure, Monday we talk gauge. Because without the right gauge, none of this information matters.