The Net Effect of Changing Length Above The Armscye (When You're Knitting Flat a Bottom-Up Sweater) with Set In Sleeves

You know I'm all about the fit and the fittedness. You may also know I'm making a retro-sweater that's supposed to fit slimly. And you can't help but to know how I'm really short in the waist and particularly from above my breasts/armsyce to the shoulder. 

Princess Jumper and Photo by Susan Crawford

Perhaps, from the pic above, you will agree that the fussy stitch pattern (let me assure you, it's fussy), which starts above the breasts, must be the perfect length or the sweater's gonna look all kinds of amateur. (One risk is that the stitch pattern could encroach towards the full bust in a kind of visual reverse of an empire seam that doesn't actually fit under the bust at the rib cage).

Which leads me to the part of this post wherein I tell you how I - when first I began knitting this - deliberately altered the length above the armsyce on the front and back pieces of this sweater without adequately considering (until I started knitting a sleeve) the shaping alterations it would require in the sleeve cap. Oh my.

Quick info: The sweater calls for an armscye depth of 8.25 inches to the shoulder. My dimensions require 6.75 inches (at the large end). 

Let's start by thanking Gail, the knitter who is metaphorically holding my hand while I figure this out and who also happened to be able to direct me to this shockingly fantastic post, even though I searched via 63 different terms to locate something that might have been half as useful, only to come up with zilch. I warn you. It's a pretty scary article. (Note: You have to understand the Pythagorean Theorum which, let's face it, I can barely spell.)

Very, very briefly, the concept is that:

• The required size and shape of a sleeve cap is entirely - and utterly irritatingly - contingent on the length of the armhole. (Sewists, you know that.) 

• Furthermore, the width of the sleeve (specifically its angle), just below the start of the sleeve cap, is mysteriously related to the shape and depth of the armscye and this is one of the many factors that determines how you shape said sleeve cap. 

• Pivotally, one must determine the angles, altitudes and lengths of the front and back armscye curves and then mathematically reflect them in the shaping of the sleeve cap. The cap is made of concave, moving into convex, curves on either side of a bisecting line (which we can view and calculate as straight edges of triangles, hence Mr. Pythagoras). Until you've calculated one element, you can't determine the other. And till you've determined the other, you can't exactly knit it.

Are you feeling a little overwhelmed? Take a moment to absorb that info, assuming it's never occurred to you either. Then be very glad you're not 3/4 of the way through this sweater having just come to the realization.

This, my friends, is the reason that picking up stitches at the armhole and knitting sleeves in the round (with sleeve cap short rows!) was invented. But it's not the best method when you're working with a vintage design because it doesn't look particularly vintage. Note that the article I've linked to above gives you all kinds of mathy tips to short row when a pattern calls for the flat, sleeve cap method (but you've got to be careful or you'll get a dreaded short-row poof - like you find in a heel or a bust curve).

In truth, aside from my utter confusion, I'm in just about the best position I could be in. Why?

• I've knitted the body in 2 separate pieces (as the pattern calls for) and all of the stitches on the front and back pieces, at the shoulder (this is bottom up, flat knitting) are on stitch holders. (Side note: Due to other math glitches, I appear to have too little length at either side of the back at each shoulder. But I can adjust this easily before moving forward with the sleeve.)

• Mercifully, I figured out I was going to have an issue before I started knitting the sleeve cap on the first sleeve so it's likely that I won't have to rip anything back.

I'm  having difficulty absorbing the complexity of the trigonometry and calculus involved in adjusting the shape and height of my sleeve cap to suit the changes I so innocently made on the front and back pieces. Note: Yeah, I was cavalier, but I did measure the bodice pieces to fit my body. And, after that, I did undertake the significant work to reorg the crazy stitch pattern to reflect the changes I needed to make. Point is, cavalier does not equal lazy (just stupid, in light of the fact that I've already dealt with this situation on a tailored jacket or two).

I'm sorting this out, she says like a deer caught in the headlights, and I will post on the details of my corrective alteration, as soon as I come up with it. (That statement fills me with hope.)

In the meanwhile, have a look at the pretty bodice pieces, such as they are at the moment:

 

Today's questions: Have you ever knit flat sleeves in a bottom up, flat pattern, and determined that you needed to change the length of the sweater above the armscye? How did you deal with the resulting change in sleeve cap shaping i.e. scary math or winging it? How did that work out for you, either way? If you've got any words of encouragement, I'm happy to take them.