Definition
Cap ease is the extra length in a sleeve cap's seam line compared with the armhole it is sewn into, eased in so the sleeve curves smoothly over the shoulder.
A set-in sleeve has to wrap around the rounded top of the arm, so its cap is drafted slightly longer than the armhole. When you sew them together, the extra is worked in evenly without forming gathers or tucks: that is easing.
Typical amounts:
| Garment | Cap ease |
|---|---|
| Fitted woven blouses and dresses | 1–2.5 cm (3/8–1 in) |
| Tailored jackets in wool | 2.5–4 cm (1–1 1/2 in) |
| Shirts, sporty and knit sleeves | 0–1 cm (0–3/8 in) |
Too much ease for the fabric creates puckers that no pressing will remove. Tightly woven fabrics such as poplin or polyester accept less than wool, which shrinks slightly under steam.
How to ease a sleeve cap:
- Sew one or two rows of long stitches, about 4 mm (6 stitches per inch), in the cap between the notches.
- Pull the bobbin threads slightly until the cap matches the armhole, with no visible gathers.
- Pin, then sew with the sleeve underneath, against the feed dogs, which help draw in the extra.
On knits, the stretch absorbs the difference, and the cap can be sewn flat before the side seams. See sleeve cap and setting in sleeves without puckers.