sword

In hand loom weaving, the sword is one of a pair of rigid bars, usually made of wood or metal, that suspend and support the lay (the frame that holds the heddles and controls the warp threads). The two swords hang from the loom frame and swing back and forth as the weaver works the treadles, moving the lay to open and close the shed, the gap between raised and lowered warp threads through which the shuttle passes.

The sword must be stiff enough to support the weight of the lay and the tension of the warp without deflecting, yet balanced enough to swing freely. Traditional swords are often flat bars of wood, typically oak or ash, measuring roughly 1 to 2 inches wide and between 3/8 and 1/2 inch thick, depending on the loom width and intended cloth weight. The suspension points, usually holes or slots near each end, attach to the overhead support via cords or metal straps. The lay itself is bolted or pinned to the swords at two or more points along their length.

As the weaver operates the treadles, the swords pivot at their upper attachment points, causing the entire lay to rise and fall. Wear and fatigue concentrate at the suspension points and at the bolts where the lay connects; wood swords can crack or split under repeated stress, especially if the loom is worked heavily or the warp is very tight. Metal swords, less common in hand looms but found in some industrial or converted machines, resist fatigue cracking but introduce different alignment problems if they bend slightly.

The term sword likely derives from the resemblance of the flat, slightly tapered wooden bar to a sword blade in profile. In larger industrial or power looms, the functional equivalent is often called a lay sword or simply part of the lay frame assembly, though the terminology varies by loom type and region. Sword condition is a frequent maintenance concern; a warped sword will throw the heddles out of square, causing uneven shed opening and thread breakage.