A wooden chassis for textile supports that has expandable corners.<br><br>Auxiliary support ??? fabric over wood, tongued and slotted at its joints to allow tightening. Stretcher Examples <br><br>Wooden bars, usually made of pine, that constitute a frame over which the canvas of a painting is stretched. Although stretchers can be any shape, most are rectangular. The edge of the canvas is attached to the stretcher with tacks, or with staples driven by a staplegun. The size of a stretcher can be changed slightly through the adjustment of keys (the small wedges visible in this example) or with expansion bolts at the four corners. A thin molding (3/4-round) should be attached to the outer edges of the stretcher, in order to keep the canvas from touching any surface other than those edges.Related link: Tips on how to stretch a canvas.