treadle
To press a specific treadle or sequence of treadles on the loom.
treadle: work the foot pedals that raise and lower warp threads
A treadle is a foot pedal mounted below a loom that operates the harnesses, the frames holding the warp threads. Pressing a treadle raises or lowers one or more harnesses in a coordinated sequence, creating the shed (the gap between raised and lowered threads) through which the shuttle passes. The weaver treads the pedals in rhythm with the loom's motion to build cloth, repeating the same sequence many times in a single weaving shift.
The mechanical linkage from treadle to harness varies by loom type. On a floor loom, the treadle connects via wooden or metal bars to a harness frame; on a pit loom, treadles hang on straps over a pit and pull down directly. The number of treadles determines which combinations of harnesses can be operated: a four-harness loom typically has four to eight treadles, allowing plain weave, twill, and simple patterned weaves. More complex looms may have ten or more treadles tied to multiple harnesses per pedal.
Weaving rhythm depends on learning the correct treadle sequence for a given weave structure. A twill, for instance, requires each treadle to be pressed in strict order to build the diagonal pattern. Mis-treading, or pressing the wrong pedal at the wrong time, breaks the pattern and creates visible flaws in the cloth. Experienced weavers internalize the sequence to the point of working without conscious thought, much like a pianist.
The physical demands of treading can be severe. Industrial weavers work treadles for eight to ten hours daily, often in high-speed conditions on hand looms or early power looms where treadle action was still manual. Repetitive strain to the legs and feet is common. On powered looms, the treadle is replaced by a cam or electronic control, but the term survives in instructions and training for traditional looms.
The word derives from Old English tredan (to tread or step). In textile terminology, it is used as both noun and verb: the weaver "treads" the treadle. The term is specific to weaving; in other trades, pedal-operated equipment may be called by the pedal's function rather than by this older word.