Abstract: A method of assembling window and glass-door casements. The casements are a rectangular frame with four profiled U-shaped and mitered channel sections joined at the corners by flat right angled fasteners. The sections have a slot shaped cavity along and in the bottom channel wall. The flat corner fasteners have two legs, each with a cross-section corresponding to the slot. The inner edges of both legs are notched and the legs of a fastener are inserted into the open ends of the slots at the ends of adjacent sections, and the sections then moved into abutment with one another over the fastener legs. The frame is placed into a press tool which includes, (preferably for each frame corner), a fixed part with two sides at right angles, and a movable part also with two sides at right angles. The latter sides have projections that correlate to the notches in the fastener legs. The movable part of the tool can be moved towards and away from the associated fixed part.