What Is An Asymmetric/Slant Welt Pocket
A slant/asymmetric welt pocket is a slash pocket application that has an irregularly-shaped welt at its opening. Traditionally, pocket welts are rectangular, fitting perfectly into the pocket opening edges. A slant/asymmetric welt goes above the rectangular pocket opening and is conventionally, blind stitched at the sides.
In the sewing process, the welt is treated similar to a pocket flap: It is stitched and clean-finished individually prior to being attached to the pocket opening. Conversely, in a traditional welt pocket application, the welt sides are left unfinished and simply stitched into the slash pocket opening sides. With an asymmetric welt, much like a flap, the pocket sides have to be finished prior to attaching the welt to its opening,
The welt is aligned to the pocket opening similar to a flap. Its raw edges should be facing inward, toward the pocket opening, and the welt's finished sides should fit perfectly within the bounds of the finished pocket opening (as marked by the hand basting above).
Once all pocket layers are brought to the wrong side of the garment (to expose the clean-finished pocket edges), the asymmetric welt will naturally flip up and cover the pocket opening. In this position, the welt's taller portion should extend above the rectangular pocket opening.
To complete the pocket application, the welt's finished sides are simply blind stitched by hand to the garment layer underneath.