# Double Two-Tie Unit System

In “Twill and Tencel for a Line of Luxury Scarves,”  Handwoven September/October 2009, page 40, Barbara Elkins writes “Plaited twills can be woven on a threading system commonly called the “double two-tie unit” system. This system allows fancier twills on fewer shafts than twill threadings.” What does that mean and why does it allow fancier twills? I’m looking at the tie-ups, but the answer isn’t jumping into my brain.

––Regina Phalanges

Hi Regina!

The name “double two-tie unit weave” is confusing because it has been applied to weaves that aren’t really “tied unit weaves.” Here’s a little history. In her 1966 Shuttle-Craft Guild Monograph Summer and Winter and Other Two-Tie Unit Weaves, Harried Tidball works to standarize our vocabulary about summer and winter and a lot of other weaves like it. She named the whole class of weaves that have a supplementary weft tied to a ground cloth with regularly spaced threads (and that are composed of threading and treadling units that can be used with block profile drafts) “tied unit weaves.”  Summer and winter, by her definition, would be be a single two-tie unit weave. Single because only one pattern shaft is used in each block, and two-tie because there are two tie-down shafts (1 and 2). It happens that there already existed a weave called “double summer and winter.” Its threading had two pattern shafts in each block (1-3-2-4) instead of one (1-3-2-3) and could produce interesting textural variations beyond the scope of summer and winter. So she called this weave a “double two-tie unit weave.”

However, its threading (1-3-2-4; 1-5-2-6, 1-7-2-8, etc.) does not have to be used for a weave with tie-down threads like summer and winter. It can be used for many different weaves, including twill. It just so happens that 2/2, 1/3, and 3/1 twills can be woven on  what we still call a “double two-tie threading” for want of a better name. The 1s and 2s can be repeated in the threading but at the same time contribute to the twill design almost as if they were on independent shafts. You would not recognize this in the tie-up; you’d have to see it in the relationship between the tie-up, the threading, and the treadling. Eunice Smith and Clotilde Barrett explored this concept in the monograph Double Two-Tie Unit Weaves (1983), which remains the best resource covering it. Eunice Smith, in fact, is the pioneer who blazed the trail weavers enthusiastically explored all during the 1980s and 1990s. It’s time to do more!