Reinforcing Slash Pocket Sides In Dressmaking
When sewing slash pockets, always stitch at the base of the side triangle extensions to reinforce the pocket opening sides.
Once you've cut the slash pocket opening and flipped all the pocket layers to the garment's wrong side, you should have a triangle-shaped extension at each pocket end. These extensions are visible underneath the garment layer at each pocket side. They should sit on top of the pocket's welt edges or pocket bag edges (depending on the type of pocket application).
To secure the pocket opening sides, it is important to stitch at the base of each triangle extension, catching the pocket layer underneath. Use a regular presser foot or zipper presser foot (if working with thick bulky layers) to apply an even straight stitch at the base of each triangle.
With this extra stitch reinforcement, the finished pocket sides are secured and lay flat, featuring a clean, straight seam.
When sewing self-welt or bound pocket applications, the base of the triangle extensions are stitched during the process of completing the pocket bag.
Start by stitching at the base of the pocket's right triangle moving down toward the bottom of the pocket bag. Pivot the stitch, and continue stitching along the pocket's bottom edge (as pictured above).
Pivot your stitch toward the pocket bag's other side edge, and stitch at the base of the left triangle extension.
When completing the pocket bag, stitching the base of the two triangle extensions will always ensure well-defined slash pocket edges that remain durable and properly reinforced throughout the garment's lifecycle.