Weaving on a treadle or dobby loom is generally faster than weaving on table loom.
We replace table loom levers with treadles, using our feet to raise the shafts, leaving our hands free to simultaneously handle the weft yarn in the shuttle.
Weaving on a four shaft treadle loom, we set up treadles thoughtfully to use all 14 combinations available. If we want to weave all 14 combinations in one piece of fabric, we can do set this more easily in a counterbalanced treadle loom, although there is a reduced shed where three shafts work against one. The more shafts we add to our loom, the more complex the choices we can make in our weaving. If I thread a four shaft loom with 2 different 2 threads blocks as in figure 1, I can weave all sorts of interesting textures such as honeycomb, however I cannot weave the twill shown in figure 2. Or vice versa. I can thread a loom with eight shafts to be able to weave both honeycomb and twill as in figures 3 and 4.
As more shafts bring flexibility in design, they also bring restrictions. An eight shaft loom has 254 combinations of lifts. (2 to the power of 8 minus 1!) The more treadles we have to use, the trickier it becomes to select the correct treadle and even remember the treadling sequence. Most eight shaft looms have only 10 to 14 treadles and and it takes time to re-tie treadles to weave different combinations of lifts.
Meet the dobby loom – a mechanical lifting device with either a system of lags or bars with pegs and holes, or a compudobby box attached to a computer. One or two treadles replace the set of multiple treadles. The weaver can change the sequence of lifts in the set of pegs in the lags, or in the computer file. The weaver uses the single or pair of treadles to weave through a sequence of lifts. No more sitting under a loom tying and retying treadles to shafts!
A dobby loom has a mechanical lifting device lifting shafts or sets of shafts, in contrast to a jacquard system which lifts individual warp threads. See my next post for jacquard weaving.