grade

Grading in textile production means cutting away layers of seam allowance at staggered heights after a seam has been stitched but before the garment is turned right side out. The goal is simple: eliminate the thick ridge that forms when multiple fabric layers stack up at the seam line. A typical graded seam might have the top layer trimmed to 6 mm, the next layer to 4 mm, and the innermost left at 3 mm, creating a tapered profile rather than a blunt edge.

The technique is essential in tailored garments, particularly at corners, curves, and intersections where seams overlap. Collars, lapels, armholes, and pocket flaps are routine candidates. Without grading, these areas pucker visibly when turned and pressed; the excess fabric has nowhere to go, creating permanent bulges or distortion. In heavier fabrics like wool suiting or linen, grading becomes mandatory rather than optional. Cotton shirting and lightweight synthetics may sometimes be graded only at critical points.

Grading is done with sharp scissors or a rotary cutter while the seam remains stitched and flat, before pressing. Some operations use a small serrated blade to remove layers in one stroke; others work methodically with shears, removing one layer at a time. The worker must cut parallel to the original seam line and avoid cutting the stitches themselves. Automated grading equipment exists for large production runs, using rotary or straight blades positioned at preset heights.

The seam allowance width dictates how much can be trimmed away. Standard allowances run 12 to 15 mm, giving room to graduate down to perhaps 2 or 3 mm at the innermost layer. If allowances are skimpy, grading becomes risky; the garment loses seam strength or the work becomes imprecise. The nature of the fabric matters too: densely woven materials hold their shape better when graded; loosely woven fabrics may fray or distort if too much is removed.

Grading and notching are often confused but serve different purposes. Notching cuts small triangular clips into curved seam allowances to allow them to spread smoothly when turned; grading removes entire layers to reduce thickness. Both may be used on the same seam: grade the straight sections and notch the curves. The term "grading" is distinct from pattern grading, which is the practice of resizing a pattern across multiple sizes.