The Knitting Fiend

In principle, designing a any type of fitted sleeve cap to fit into an armhole opening is simple. In practice, designing fitted caps to fit in the armhole involve pesky calculations. Clearly, this is the job for another knitting calculator!

Today, I'm going to describe how to calculate a simplified set in sleeve cap and also provide the calculator. Before going further, I want to briefly describe the principle. It's pretty easy.

Examine the schematic to the left. At the top, the schematic shows the right hand side of sweater front joined together at the shoulder and turned on their side. Below, a sleeve is placed near the armhole. One half of the sleeve cap is outlined in red as is the armhole opening on the front piece.

The general principle for cap design, which applies to sleeve cap/armhole variations is this:

These two curved red lines should be approximately the same length.

That's it. That's the principle. The idea underlying the principle is this: You need to sew that sleeve into the hole, and you don't want it to pucker. So, the length of the two seams need to match.

While this is the general principle, I must admit two things. First, some violations are permitted to achieve style variations. For example, if you actually want a puff sleeves, you do make the length of the red curved line on the sleeve cap longer. Second, some designers like to make the length of the red line on a very fitted caps up to 10% longer than the armhole. The extra length permits the cap to be eased into the hole and can be useful if the cap is curved. When sewing with woven garments, the extra length becomes essential and some precision is required to determine the best correct length to permit easing without resulting in gathering. However, knit fabric stretches and forgives a certain degree of mismatch; the knitter does not need to fret they are 2% off on their calculation.

Now, I'll proceed to illustrate this principle on a simplified cap that looks fairly fitted, but which results in simple knitting directions. The knitted cap will look like the one in the schematic. True fitted sleeve caps have a bell shaped cap; this simplified one will use "straight line" shaping. When knit from the bottom up, this type of cap is shaped by binding off a few stitches under the arm; I've illustrated these in violet. Afterwards, stitches are eliminated at a rate of one stitch every two rows. Finally, all remaining stitches are bound off, resulting in a wide flat region at the top of the sleeve.

I want to pause to provide and answer to this question: Why decrease one stitch every two rows? This is an arbitrary choice. In fact, this is "the "simplification compared to a fully fitted fitted sleeve which would have a bell shaped cap.

Now, examine the sweater body and its armhole opening. At chest level, a front or back has enough stitches to create the desired body width at the bottom of the armhole. At shoulder level, the front and back have enough stitches to create the desired shoulder width . The precise method of shaping to vary the sweater width depends on the style chosen by the designer. I'll describe the shaping as knit from the bottom to the top.

If knit from the bottom, the armhole is shaped by first binding off a few stitches under the arm. As a general rule, the number of stitches bound off should match the number bound off for the sleeve. This makes it easy to sew those two flat parts together. Afterwards, stitches are bound off at a rate of 1 stitch every 2 rows until the shoulder width is achieved. Notice this is the same rate of binding off as on the cap. Choosing the same bind off rate for both pieces isn't necessary, but it makes it easy to match rows on the garment and sleeves in this area, and simplifies seaming. I then knit without shaping until the armhole depth is achieved. Afterwards I shape the shoulders, but this detail is not shown in the figure.

Now, for the knitty gritty: creating knitting directions that result in the correct sleeve cap. Almost anyone can figure out the directions to shape the armhole based on the verbal description above. However, to design this cap we need to figure out

• How many stitches are in the biceps.
• How many stitches do we bind off at the underarm.
• How times do we decrease at a rate or 1 stitch every two rows and
• How many stitches will remain at the top of the cap.

However, to figure the answers to the last three bullets, we must first design the armhole. So, I'll explain by way of example. The example will be in the form of a calculator, so if you want, you can change the number to match your sweater design.

I posted the generators to create a seamless raglan cardigan sweater pattern at my web site. Jim’s been busy getting ready for a conference in France, so I haven’t gotten Jim to pose for a good picture yet, so I’m rerunning the picture of the sweater laid out on the table.

The pattern generator has pull down menus to select men’s, women’s and children’s sizes, and creates a a pattern for a basic seamless cardigan knit from the bottom up. The basic pattern doesn’t describe the embellishments I added. To do that, I’d need to add more pulldown menus to let the user select “pockets vs, no pockets” and “fancy shoulder trim vs. no trim”. Beginning users get intimidated.

Those who were reading the blog was I knit the sweater know I have lessons for the cables and pockets. Links to lessons describing how to add pockets are provided on the pattern page.

I’d post the generator here inside the blog but it’s just too long! So, if you want to click the button and pop up a pattern for a sweater visit the pattern page, then click the button!

I finally finished this. (Except for blocking. I’ll do that now.)

I think I cast on for this in May! Anyway, the sweater pattern generator is written, but the page isn’t ready for prime time. I need Jim to model the sweater. I ‘ll block this tonight.

I knit to fit, so blocking doesn’t do a whole lot. But, the sweater will just look crisper after I wet it and let it dry flat. Afterwards, I’ll force, force, force Jim to pose, and I’ll get the final touches on the generator. Then I’ll post the address to the generator so people who want to knit a raglan cardigan can.

It’s sort of interesting to see the yarn looks more striped in the photo than in real life. That’s consistent effect. It looks more striped in every photo I’ve taken– whether indoors or outdoors. When I see the sweater in real life, the stripes are subtle.

Maybe if I were a photographer I would understand why?