Abstract: An improved method and apparatus for forming notches at a fold for the corner portion of an expandable gusset envelope, such as a file pocket. A pleated gusset member is placed on a ridged upper surface of a table structure of the apparatus, thereby initiating operation of the apparatus. The bottom portion of the pleated gusset member is clamped against the top of the table. Pressing rolls bend the end portion of the clamped gusset member downwardly against a ridged side surface of the table. The pressing rolls then are rolled upwardly with respect to the pleats of the end portion and form notches adjacent the fold at the clamped bottom portion of the gusset member. A plurality of stacked and gusset members can be notched at one time.