We’ll show you how to fix a large diamond-shaped hole, and later, there are special instructions for small holes. A gusset is cut on the bias of the fabric, which means on the diagonal of the threads that are woven to create the fabric. See the illustration above. The straight grain and cross grain intersect to make the material. Cut a gusset so that these lines are on a diagonal. This makes the gusset stretchy in the direction that you need it to be. You’ll need to cut a gusset that is at least 5/8" larger than the hole in your armpit. Position the gusset on the diamond-shaped hole so that the right-side of the gusset edges and hole fabric edges are together. Pin the gusset and shirt together. Stitch the patch to the edges of the hole, leaving 5/8" seam allowance, as shown. Position the gusset on the triangular hole so that the right-side of the gusset edges and hole fabric edges are together. Pin the gusset and shirt together. Stitch the patch to the edges of the hole, leaving 5/8" seam allowance. Try inserting gussets into any shirt that is a little tight in the armpits. This will prevent holes in the future and generally make you feel more comfortable in stiff fabrics.
