Well-fitting sleeves often determine whether you'll wear a garment or not. Here are suggestions for altering patterns to accommodate both large or small arms. Begin by determining the amount of ease you'll need. If you're making a knit dress, 1-1/2 inches to two inches under the armhole is about right; any smaller and the fit will be too tight. For a jacket, four inches is more appropriate so a sweater can fit underneath.
Determining the Sleeve Width
Using a one-piece jacket pattern, measure 1-1/2 inches down from the armhole and 5/8 inches away from the edge. Don't measure in the seam allowances. Next, measure from one side to the other to get the width of the sleeve. (For example, if it measures 15 inches, it would fit an arm 11 inches around.) Using a two-piece sleeve pattern, fold a seam allowance under and overlap it where the seam would be. Again, as above, measure from one side to the other to determine the width.
Two Alterations for Large Arms:
Alteration 1: Adding a sleeve seam
- If your arm is full in comparison with the rest of your body, you may want to take a one-piece sleeve and cut it apart--down the middle--to insert a seam. It creates a style line as well as makes the sleeve larger. (If you are using a two-piece pattern and now want to eliminate one of the seams, fold the seam allowance under the arm and pin it together so that you are back to a two-piece pattern.)
- Place paper behind the pattern and tape.
- With a pen, mark a new pattern along the cut. Increase the girth at the top by the amount needed and taper it to the bottom, where it isn't needed.
- Remember to add a seam allowance back on.
- Repeat on the other half.
- Another method, if you don't want to put ease in, is to draw a line cross grain and put it on the bias.
Alteration 2: Enlarging the sleeve
- To eliminate a sleeve seam, take a ruler and draw a line down the center from the shoulder to the bottom of the sleeve.
- Then from the armhole area, draw a line across.
- Add paper behind.
- Cut along each line, stopping about 1/8" from the edges. This allows you to add fabric while keeping the armhole the same.
- Spread pattern to amount needed. Tape to paper behind the pattern. Don't shorten the sleeve cap.
- In order to account for the spread and allow the pattern to flatten, the side cuts will begin to overlap in the center. This is fine but may make the sleeves shorter. If so, add more paper to the bottom to lengthen.
Alterations for Small Arms
- A small arm doesn't need as much ease as a large arm. If you want to remove width, take a ruler and draw a line down the center length of the sleeve; then draw another line the distance apart you want to lose.
- Fold the pattern together--one line along the other--and tape. (Remember, for example, a 1/2-inch fold takes out an inch.)
- Trim to smooth sleeve top, if jagged.
