Every woven cloth answers one question: which warp threads lift?

A loom holds the warp under even tension, opens a shed, and lets you beat each pick home. What separates one loom from another is mostly how that shed is opened.

Frame and tapestry looms have no shedding mechanism beyond a shed stick and string heddles, so every shed is made by hand. Slow, but nothing is fixed in advance: this is the right tool for tapestry, samplers and small weft-faced work.

A rigid-heddle loom uses a single slotted-and-drilled heddle. Raise it and the ends in the holes rise; drop it and they sink. Two sheds — plain weave, plus whatever you add with pick-up sticks. It warps in an evening and folds away.

Shaft looms carry heddles on four, eight or more shafts, each lifting a chosen set of ends. A table loom works them with hand levers: slower, but every combination is available, which is why it suits sampling. A floor loom moves them with treadles, so both hands stay free and throw, beat and change become one rhythm.

Floor looms differ again in the shedding action. Jack looms push shafts upward. Counterbalance looms hang them in pairs over rollers — quiet and even, but unhappy with uneven lifts. Countermarch looms tie every shaft both up and down for a deep, level shed, at twice the tying-up.

The warp is held under tension on the loom; the weft crosses it. Warp is abraded by heddles and reed on every pick, so it wants a smooth, strong, low-stretch yarn — plied cotton, linen or worsted. Weft is only carried, so it can be softer, thicker or more interesting.

Sett — ends per inch — changes the finished cloth more than any other single decision. Wrap the yarn round a ruler to find its wraps per inch, then take about half of that for plain weave and about two-thirds for twill, which interlaces less often and so packs closer. Picks per inch near the sett gives balanced cloth; much more weft gives a weft-faced surface, much less a warp-faced one.

Warp longer and wider than the piece you want. Take-up — thread bending around its partner — plus shrinkage in the wash costs roughly a tenth of each direction, and every loom keeps a fixed length of warp that cannot be woven, usually somewhere between 60 and 90 cm.

Two habits then decide quality. Keep tension even across the whole width, front to back. And lay each pick in at a slant, or in a shallow arc, so the weft has the length it needs to bend around the warp instead of dragging the selvedges inward.

A draft is four panels describing one cloth, always in the same relationship. Threading runs across the top: the shaft each warp end is heddled on. The tie-up sits in the corner — which shafts each treadle lifts, one filled square per raised shaft. Treadling runs down the side and is read downward, one square per pick. The drawdown fills the remaining block: the cloth itself, filled where warp lies on top, blank where weft does.

Two numbers name a structure. A 2/2 twill lifts two ends and leaves two down on every pick, so both yarns show equally; 1/3 lifts one and drops three, so weft covers the face. Those numbers are also the float — how far a thread travels before it interlaces again. Long floats snag and wear, which is why satin, floating over four, wants smooth yarn and a close sett.

The draw is a separate lever. A straight draw, 1-2-3-4, turns a twill tie-up into a continuous diagonal; reverse it at a point and the same tie-up mirrors into chevrons. Change only the treadling order and the cloth changes again with nothing re-threaded. The previewer below is that experiment.