Learning to make tidy seams is an important skill in the production of high quality garments and sewing projects. Good seaming with sewing machines does take some practice; however, the benefits of learning things like grading seam allowances is well worth the effort. Seam grading is a simple technique that reduces the bulkiness of seams sewn with Juki sewing machines like the Juki TL2000Q1. It creates a smooth, finished garment by removing bits of fabric in areas where seamed fabric might otherwise layer thickly. A graded seam allowance helps turn any sewing project into a professionally finished garment that will lay correctly without unsightly ripples and bunches.
What Is Seam Grading?
Seam grading is the process of trimming away excess fabric, also called the seam allowance, after sewing a seam in order to prevent bunching and rippling on the underside of the garment. Grading a seam allowance produces a smooth seam when multiple layers of fabric are sewn together at seamed corners, or when sewing curved seams that could otherwise leave ripples of fabric behind.
Grading Faced Seams
Creating tidy, faced seams requires little more than trimming seam allowances so that fabric lays in steps, gradually fanning outward rather than lying in one stack. Working on the underside of the project, duckbill scissors should be used to trim the innermost layer of the excess seam fabric so that it extends only about â ” from the seam line. The next layer of fabric should then be trimmed so that it extends about â ” beyond the trim of the first layer.
Trim any additional layers the same way, so there is a gradual slope down to the main fabric, allowing the seam to lay flat from the right side without looking bulky. Graded seam allowances on any faced seams sewn on sewing machines should loosely resemble a staircase.
Grading Corner Seams
Seams sewn in corners can cause bunching of the extra fabric, so it is best to trim this away. Grading the seam allowance of a corner seam is very easy. The excess fabric should be trimmed off at a 45-degree angle, cutting close to the seamed corner, but not cutting over it. With an angled corner, seams sewn on machines such as the Juki TL2000Q1 sewing machines can be shaped without corners that are filled with excess fabric, making a flat corner impossible.
Grading Curved Seams
Grading a seam allowance on curved seams can be a bit trickier, as it involves a combination of both techniques mentioned above. First, seams such as a straight, faced seam should be trimmed by cutting the innermost layer close and trimming the next layers about â ” beyond each previous layer. Cuts must be carefully trimmed along a curve designed to give stretch room or excess fabric removed depending on the shape of the curve.
For an inside, concave curve, make horizontal cuts in seam allowances almost to the stitch line, enabling seam allowances to expand with movement. For an outside, convex curve, cut ‘V’ cuts into seam allowances, removing excess fabric from seams to prevent fabric bunching.
Regardless of the type of sewing machines used to create garments, making a flat seam involves a little bit of extra attention. After creating seams with Juki or other brands of sewing machines, it is important to go back and trim excess fabric at the seam to minimize bunching and layering. By grading seam allowances, it is possible to turn seams right side up and iron them flat without having the problem of excess fabric on the underside. Owners of sewing machines can easily put this important tip into practice and take their garment making techniques to the next level!