Making a plain seam and neatening it

1Why this matters

The plain seam, also called the open seam, is the most common seam in clothing. It is quick, flat and suits most medium-weight fabrics, including the cotton kitenge sold in Rwandan markets. Its one weakness is that its raw edges are left inside the garment, so they must be neatened or the seam will fray apart in the wash.

In this lesson you will make a plain seam step by step, press it, neaten it, and deal with curved seams.

2Making a plain seam, step by step

1. Place the two pieces with their right sides together, raw edges level and notches matching.
2. Pin across the stitching line, at right angles to the edge, about every 8 to 10 cm.
3. Tack along the stitching line, 1.5 cm from the raw edge, with stitches about 1 cm long. Remove the pins.
4. Stitch by machine just beside the tacking, on the allowance side, keeping the raw edge against the 1.5 cm mark on the machine's needle plate. Reverse for about 1 cm at the start and end to secure the stitching. By hand, use a small backstitch.
5. Remove the tacking.
6. Press. First press the seam flat, as it was sewn, to set the stitches. Then open the allowances out and press them apart with the point of the iron on the wrong side.
7. Neaten each raw edge with one of the seam finishes below.

3Seam finishes

A seam finish secures and neatens the raw edges of the allowances so that they do not fray.

Ready-made clothes are usually neatened with an overlocker, a machine that trims the edge and wraps it in thread in one go.

4Curved seams

On a curve, such as a neckline or armhole, the allowance must be cut so that it lies flat when turned:

• On an inward (concave) curve, make small straight cuts, called clips, into the allowance, stopping 2 to 3 mm from the stitching, so the edge can spread.
• On an outward (convex) curve, cut out small V-shapes, called notches, so that the extra fabric does not bunch up.

Worked example: planning a skirt side seam

Keza is joining the side seams of a cotton kitenge skirt, each 60 cm long, on a machine set to a stitch length of 2.5 mm.

(a) How many stitches are in one side seam? 60 cm = 600 mm, and 600 ÷ 2.5 = 240 stitches.

(b) Which finish should she use? Kitenge is a woven cotton that frays when washed, and a skirt is washed often. Pinking would not hold. A machine zigzag is quick and secure, so it is the best choice; turned-and-stitched would also suit this light cotton.

Practice

Solution. When the pieces are opened out, the stitching and the allowances end up on the inside (wrong side), and only a neat line shows on the right side.

Solution. The reverse stitches lock the thread ends so the seam cannot unravel from its ends.

Solution. (a) Pinked: felt does not fray, and a folded finish would be too bulky. (b) Bound: it looks neat when the inside is seen and it stops the light cotton from fraying.

Solution. 30 cm = 300 mm, and 300 ÷ 2 = 150 stitches.

Solution. The curved allowance was not clipped (an inward curve) or notched (an outward curve), so it cannot spread or close up to fit the curve.