noun – A sleeve joined to the body of a garment by a seam starting at the edge of the shoulder and continuing around the armhole.
from the GNU version of the Collaborative International Dictionary of English.
In a blouse or shirt, I find 1/2-5/8” of ease works the best. In a jacket or coat, the sleeve head ease is increased to 3/4-1 1/4”.
CONSTRUCTION DIRECTIONS – Baste in by machine gathering stitches.
1. Use the longest stitch your machine has.
2. Sew the basting stitches with the right side of the fabric up. You will be pulling the bobbin basting stitches (wrong side of fabric). This will enable you to adjust the stitches when you place right sides of fabric together when you attach them. AND, the bobbin thread tension is slightly looser making gathering easier.
3. Start your basting stitches at the notch/notches. ✔️Double notches indicate this is the side that attaches to the body back.
4. On a pattern that uses 5/8” seam allowances, start your basting stitch 1/2” from the raw edge. Stitch from notch to notches (left sleeve) and notches to notch (right sleeve). Pivot with the needle into the fabric toward the center of the sleeve, stitch 2 stitches. Pivot with the needle on the fabric to return stitching 3/4” away from raw edge, parallel to the 1/2” basting stitch.
5. Stitching the basting lines 1/8” on each side of the seam stitching line prevents accidental pleating as you sew in the sleeve in.
6. Sewing Tip – pull the basting threads until you have gathers, then release all the gathers. There will be ease left that in most cases the perfect amount of ease allowing you to sew in the sleeves without puckers 🤗.
7. Sew the underarm seam and finish the seam allowances in you preferred method.
8. Sew in the sleeve in a continuous seam all around the armhole. Pin the left sleeve to the left armhole. That may sound obvious but you have a 50% chance of doing it wrong if you are not paying attention. First pin in the sleeve underarm seam to the side seam with the right sides of the fabric together. Next pin in the shoulder seam to the top dot on your sleeve. (I am not going into adjusting the correct hang of the sleeve in this construction directions, that is covered in fitting a muslin). Pin in the remaining sleeve starting with the side you pivoted the basting stitches.
Too Much Ease in your Sleeve head?
If you are using a commercial pattern, an easy solution to reduce your ease is to draw a perpendicular line to the grain line in the sleeve head. Draw a second line parallel to the first line half the excess ease you need to take out. Fold along one line and place on second line. Tape together. It does not matter which line you fold, it comes out the same. True the edges if necessary.
If you need to add ease, draw the same first line. Extend drawing the grain line up to the top of the sleeve head. Cut and spread half the distance of the ease you need. Align the grain lines together. True or blend the edges of the sleeve head.