Editing Loom (section)

====Treadle-controlled looms====
In treadle looms, the weaver controls the shedding with their feet, by treading on [[treadle]]s. Different treadles and combinations of treadles produce different sheds. The weaver must remember the sequence of treadling needed to produce the pattern.

The precise mechanism by which the treadles control the heddles varies. Rigid-heddle treadle looms do exist, but the heddles are usually flexible. Sometimes, the treadles are tied directly to the staves (with a Y-shaped bridle so they stay level). Alternately, they may be tied to a stick called a ''lamm'', which in turn is tied to the stave, to make the motion more controlled and regular. The lamm may pivot or slide.

[[Counterbalance loom]]s are the most common type of treadle loom globally, as they are simple and give a smooth, quiet, quick motion.<ref name="glim_types"/> The heald frames are joined together in pairs, by a cord running over heddle pulleys or a heddle roller. When one heald frame rises, the other falls. It takes a pair of treadles to control a pair of frames. Counterbalance looms are usually used with two or four frames, though some have as many as ten.<ref name="glim_types"/> 

In theory each pair of heald frames has to have an equal number to warps pulled by each frame, so the patterns that can be made on them are limited.<ref name="ask_Madelyn"/> <!--although the number of sheds can be increased by adding heddle sticks and shedding sticks as supplementary shedding devices.{{cn}}--> In practice, fairly unbalanced tie-ups just make the shed a bit smaller, and as the shed on a counterbalance loom is adjustable in size and quite large to start with (compared to other types of loom), so it is entirely possible to weave good cloth on a counterbalance loom with unbalanced heald frames,<ref name="js_diff_types">{{cite web |title=Different types of looms – Jane Stafford Textiles |url=https://janestaffordtextiles.com/knowledge-base/different-types-of-looms/ |website=janestaffordtextiles.com |access-date=3 December 2024}}</ref><ref name="glim_types"/> unless the loom is extremely shallow (that is, the length of warp being pulled on is short, less than 1 meter or 3 feet), which exacerbates the slightly uneven tension.<ref name="glim_types"/> Limited patterns are not, of course, a disadvantage when weaving plainer patterns, such as tabbies and twills.

[[Jack loom]]s (also called single-tieup-looms and  rising-shed looms<ref name="JackloomsP1"/>), have their treadles connected to jacks, levers that push or pull the heald frames up; the harnesses are weighted to fall back into place by gravity. Several frames can be connected to a single treadle. Frames can also be raised by more than one treadle. This allows treadles to control arbitrary [[combination]]s of frames, which vastly increases the number of different sheds that can be created from the same number of frames. Any number of treadles can also be engaged at once, meaning that the number of different sheds that can be selected is two [[to the power of]] the number of treadles. Eight is a large but reasonable number of treadles, giving a maximum of 2<sup>8</sup>=256 sheds (some of which will probably not have enough threads on one side to be useful).{{Cn|date=December 2024}} Having more possible sheds allows more complex patterns,<ref name="ask_Madelyn"/><ref name="JackloomsP1">{{cite web |last1=Joanne |first1=Hall |title=Jack Looms - part 1 |url=https://fiberarts.org/design/articles/jackloom1.html |website=Fiberarts.org |publisher=Fiber Arts |access-date=3 December 2024 |date=30 May 2019|archive-url=https://web.archive.org/web/20190530012643/https://fiberarts.org/design/articles/jackloom1.html |archive-date=30 May 2019 }}</ref> such as [[diaper weave]]s.{{cn|date=January 2025}}

Jack looms are easy to make and to tie up (if not quite as easy as counterbalance looms). The gravity return makes jack looms heavy to operate. The shed of a jack loom is smaller for a given length of warp being pulled aside by the heddles (loom depth). The warp threads being pulled up by the jacks are also tauter than the other warp threads (unlike a counter balance loom, where the threads are pulled an equal amount in opposite directions). Uneven tension makes weaving evenly harder. It also lowers the maximum tension at which one can practically weave.<ref name="ask_Madelyn"/><ref name="JackloomsP1"/> If the threads are rough, closely-spaced, very long or numerous, it can be hard to open the sheds on the jack loom.<ref name="JackloomsP1"/> Jack looms without castles (the superstructure above the weft) have to lift the heald frames from below, and are noiser due to the impact of wood on wood; [[elastomer]] pads can reduce the noise.<ref name="glim_types"/>

[[File:Schloss Heubach, historischer Handwebstuhl im Miedermuseum.jpg|thumb|upright=2.5|A countermarch loom, with upper staves attached to the outer ends of the jacks, above. Below the heddles, there are two rows of lamms. The inner ends of the jacks are tied, in bridled pairs, to the upper lamms, which are tied to the treadles. The lower lamms are tied to the bottom staves and to the treadles. The roles of the upper and lower lamms may be swapped.<ref name="xeniakis"/>]]

In [[countermarch loom]]s, the treadles are tied to lamms,<ref name="xeniakis">{{cite web |last1=XENAKIS |first1=DAVID |title=ABOUT TYING UP A COUNTERMARCH LOOM |url=https://www.weaversschool.com/docs/Countermarch.pdf |access-date=3 December 2024}}</ref><ref name="ask_Madelyn">{{cite web |last1=van der Hoogt |first1=Madelyn |title=Ask Madelyn: Jack Looms and Counterbalance Looms |url=https://handwovenmagazine.com/looms/ |publisher=Handwoven Magazine |access-date=3 December 2024 |language=en}}</ref> which may pivot at one end or slide up and down.<ref>{{cite web |title=Different types of looms – Jane Stafford Textiles |url=https://janestaffordtextiles.com/knowledge-base/different-types-of-looms/ |website=janestaffordtextiles.com |access-date=3 December 2024}}</ref> Half of the lamms in turn connect to jacks, which also pivot, and push or pull the staves up or down.<ref name="xeniakis"/> Some countermarches have two horizontal jacks per shaft, others a single vertical jack.<ref name="glim_types"/> Each treadle is tied to ''all'' of the heald frames, moving some of them up and the rest of them down.<ref name="glim_types">{{cite web |title=Types of Looms {{!}} Learning About Looms |url=https://www.glimakrausa.com/types-of-looms/ |website=Glimakra USA |access-date=3 December 2024 |language=en}}</ref> This allows the complex [[combination|combinatorial]] treadles of a jack loom, with the large shed and balanced, even tension of a counterbalance loom, with its quiet, light operation. Unfortunately, countermarch looms are more complex, harder to build, slower to tie up,<ref name="xeniakis"/><ref name="ask_Madelyn"/><ref name="glim_types"/> and more prone to malfunction.<ref name="xeniakis"/><ref name="treadle_diagrams">{{cite web |title=Counterbalance Loom, Jack-Type loom, Countermarch loom and NEW Jack-Type loom with back hinge treadle: TECHNICAL INFORMATIONS |url=http://www.leclerclooms.com/cont.htm |website=www.leclerclooms.com |publisher=LeClerc Looms |access-date=4 December 2024}}</ref>
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