heddle

A heddle is a loop of wire, cord, or fabric that carries a warp thread on a weaving loom. Each heddle has an opening—the eye or slot—through which a warp thread passes. Heddles are mounted on loom shafts (harnesses); groups of heddles form a shaft. When a shaft is raised or lowered by the loom’s treadles or by a dobby, the warp threads threaded through that shaft’s heddles move, opening a shed for the weft to pass through.

Heddles come in several forms. The common metal heddle is an eye heddle, a small loop with an eye for the warp thread. Some heddles are slotted to guide the thread. Flexible heddles may be made from cotton, linen, or synthetic cords and are used on handlooms or backstrap looms. The total number of heddles on all shafts is the loom’s heddle count; a higher count allows more warp threads to be controlled in shedding. The choice of heddle type affects warp friction, durability, and maintenance.

In use, heddles are replaced when worn; damaged heddles can cause misalignment or snagging of warp threads. Metal heddles tend to be durable and precise, while cord heddles are simpler and cheaper but can stretch. Heddles are essential to warp geometry in a wide range of weave structures, from plain weave to twill and satin, enabling the loom to produce complex patterns.