Every woven cloth comes from the same three moves, repeated endlessly
Whether it is a stick frame in a nomad's tent or a powered factory machine, a loom has one core job: keep a set of lengthwise threads tight so a crosswise thread can weave over and under them. Everything else, from foot pedals to punched cards, exists to make three repeating motions faster and easier.
The stretched lengthwise threads are the warp, a word traced to an ancient root meaning to bend, and the thread passed across them is the weft. Usually the warp runs between two beams held apart to keep it taut. The warp beam at the far end can unroll as work proceeds while the woven cloth winds onto the cloth beam near the weaver, so a loom can produce fabric far longer than itself. Some looms manage with a single beam: on a warp-weighted loom the threads hang down and are kept tight by dangling weights.
The first of the three motions is shedding, pulling some warp threads aside to open a gap called the shed. Next comes picking, sending the weft through that gap once; a single crossing is a pick. Last is battening, pressing the new weft firmly against the finished edge, known as the fell, so no loose gaps remain. Lift the odd threads, then the even ones, and you get the simplest cloth, tabby weave. Twill, satin and picture-forming weaves need more sheds and more complex sequences. A conventional shuttle loom manages around 150 to 160 picks a minute, and a fully automatic one also needs a stop motion that halts it if the weft snaps.
The devices for making sheds range from humble to ingenious. A heddle-bar is just a stick tied to every other warp thread, needing nothing but wood and yarn, yet it allows elaborate brocades on vertical and backstrap looms. Tablet weaving twists punched cards to make narrow decorative bands. On treadle looms the weaver's feet choose the sheds, freeing both hands for the shuttle, though the weaver must remember the whole treadling sequence for the pattern.
Loom design also follows the weaver's life. People on the move favour light, portable frames, while city weavers short of space choose tall upright looms or ones that fold away.
Source: Loom
