So that's what I used for Take 2: Success!
If you didn't read about my inspiration and first attempt, find it here...!
Note: I originally put together this tutorial while making my first version, so the images a mash up of the two... I hope it isn't confusing!
A note about choosing a pattern:
Perhaps you have a simple jacket pattern filed away somewhere with a one-piece sleeve. This is the ideal.
Perhaps you have a sloper. This is what I used, leaving an inch all the way around to account for comfy-fit ease and seam allowance. It worked like a charm.
Perhaps you have a pattern of some other kind with a one-piece sleeve. This shouldn't be a problem, just take the fit of the pattern into consideration and cut it bigger if appropriate to allow for a loose fit.
Perhaps you only have patterns for sleeves with cuffs or short sleeves. I wouldn't recommend this unless you know what you're doing, but you could perhaps use the cap and extend the sleeve length.
You will also need the front and back bodice pieces from the same pattern to create your armhole.
The Basic Measurements:
Obviously, these are up for interpretation if you aren't a size 8 or want it to fit differently than mine.
To begin, cut and finish any raw edges on your main rectangle.
To Assemble Your Sleeves:
***With fabrics that have indistinguishable front and back sides, be sure you sew them opposite, so you have one left and one right sleeve!
Now this here is a make-it-or-break-it (as I learned)...
1. Fold your main rectangle in half lengthwise.
2. Measure down 11" from the top, and over 9" from the fold. This is the top center of your armhole.
3. Using the front and back bodice pattern pieces from the same pattern you snatched your sleeve from, place the back bodice piece parallel to your center fold with the top corner of the armhole at the point you've measured, 11" down and 9" over.
4. Place the front bodice piece so that together they create a nice armhole shape. (Mine are so far apart because I added ease to my sleeves when I cut them out).
5. Mark this shape with tailors chalk, rounding out any harsh corners.
6. Cut along your chalked line, through both sides.
1. Check for where you marked your sleeve cap. One notch means it goes towards the front, two means it goes towards the back. Make sure you have left and right sleeves on the appropriate sides.
2. With your sweater body inside out, and your sleeve right side out, match the sleeve to the armhole, underarm down, sleeve cap up.
3. Start pinning at the underarm. Pin the sleeve flat to the body in the underarm. Pin from inside the sleeve to the body, so that you can easily remove the pins as you sew.
4. If your sleeve cap is bigger than your armhole, this is okay! This is called ease. Ease should be evenly distributed between your front and back notches.
As an old teacher of mine used to say, sew as if your presser foot is a hamster and your armhole is a wheel. This is to avoid accidents like puckers and catching other parts of your sweater in the seam.
Congratulations! You're finished!