Threading double weave on 4 shafts

In this post I will look at two different threadings which allow you to weave double cloth on a 4 shaft loom. You will find both of these approaches in the weaving literature. They achieve exactly the same result, but it is useful to look closely at how they do this.

The starting point

If you are weaving on a shaft loom, you know that it takes two shafts to make plain weave. So, if you have four shafts, you can divide them notionally into two sets with two shafts in each set. You can use each set to weave a piece of cloth in plain weave, and hence you can weave two layers of cloth at the same time. This is where our double weave journey begins.

Which shafts to choose

There are two main approaches to dividing your shafts into pairs. One I will characterise as the odds versus evens approach (often referred to as a straight threading) and the other as the front and back approach (often referred to as a parallel threading).

Odds versus evens

In this approach, one layer is threaded on the odd-numbered shafts (1 and 3) and the other on the even-numbered shafts (2 and 4). This gives us a straight draw:

In this draft one layer is indicated by the light pink squares, the other by the dark blue squares.

This threading has a couple of important points in its favour. One is that a straight draw is just about the easiest draft to thread. You have probably used this threading before for weaving other structures, so the only thing that you need to watch out for is making sure that you get the right colour on the right shaft. Reading from the right, I need to maintain a blue-pink-blue-pink alternation as I proceed. This is something which you can build into your warp-winding process (we will look at the practicalities of winding a warp for double weave in a later post).

Another advantage of the odds vs evens principle is that you can very simply expand it to whatever number of shafts you have available. If you have eight shafts, then 1 and 3 becomes 1, 3, 5 and 7, while 2 and 4 becomes 2, 4, 6 and 8.

Given that it is so easy, why would you ever think of doing anything else?

Front and Back

I actually tend to use this method, which involves threading one layer on the frontmost shafts (1 and 2) and the other on the shafts at the back (3 and 4). The individual layers look like this:

So, when we put them together, the whole threading looks like this:

Reading from the right, I am still threading blue-pink-blue-pink as before, but now instead of the straight draw I am threading on shafts 4-2-3-1.

An important point to note about this approach to threading is that, as you increase the number of shafts you are using, the choice of shafts for each layer typically changes. On eight shafts, for example, you would usually use all of shafts 1 – 4 for one layer, and assign shafts 5 – 8 to the other.

What they have in common

The most important thing to note about these drafts is that both are threaded in a 1:1 ratio. That is, every thread from one layer is followed by a thread from the other layer. This is based on the assumption that both layers will be woven with the same thickness of yarn, which is a good starting place for working with double weave.

Another thing to note is that both drafts assign blue threads to two shafts and pink threads to the other two shafts: there are no shafts shared by both layers. We could turn the odds vs evens draft into the front and back draft simply by exchanging shafts 2 and 3.

Adopting an approach

You will come across both of these approaches to organising your double weave threading, so it is a good idea to get to know and recognise them. However, you will probably find that you settle on working predominantly with one or the other as being more comfortable for you.

I have already outlined some advantages of the first option, but what about the second?

The main advantage of the front and back approach comes after you have finished threading. Dividing the shafts so that each layer occupies an adjacent pair can make it easier to plan and execute the lifts you need to make your design.

If you are weaving on a table loom which has the levers facing you in a row at the front, then you can easily raise or lower a whole layer in one go. The same logic applies to tying up treadles or pegging a mechanical dobby, and the advantage is increased the more shafts you are using. A block of four shafts together (for one layer of an 8-shaft double weave) can be easier to work with visually than four shafts which are spread out.

As my weaving design process often entails improvising liftplans on an existing threading (by moving pegs around dobby bars) the front and back approach suits me best, and it is the approach I teach to my students using table looms with front-facing levers. This is therefore the threading which will be the basis of my future posts. However, if you prefer to thread a straight draw and work with odds versus evens, then you can easily make the shaft switch I have described. (Fiberworks weaving software even has a tool which allows you to move shafts around at your leisure: look for something called a shaft shuffler in your menu.)