/blogs/how-to-weave/how-to-convert-a-rigid-heddle-patterns-for-a-4-shaft-or-2-shaft-loom

How to Convert Rigid Heddle Patterns for 4-Shaft Looms

by Christine Jablonski

So you found a great project you’d love to weave, but the pattern was written as a rigid heddle project and you are a shaft loom weaver. Can you still weave this project? Absolutely! In this article we’ll show you how to convert a rigid heddle project to a shaft loom draft in a few easy steps.

First, assess the technique: is the project a plain weave or float-technique project? Many of our rigid heddle projects are plain weave, but we have a few weft float patterns as well. This post will go over instructions for converting plain weave, color-and-weave, and weft float drafts. 

Converting Plain Weave and Color-and-Weave Structures

Using theTextured Cotton Scarf as an example, we see the instructions are to sley one end per hole and slot in a 12-dent reed and weave plain weave. Plain weave in rigid heddle weaving is simply plain weave with 2 shafts, which translates to a shaft weaving draft like this:

plain weave draft on two shaftsOr it can be converted to a 4 shaft draft threaded in a straight draw (4-3-2-1 or 1-2-3-4, depending on your preference) and treadled 1-3, 2-4. 

4-shaft draft

This also applies to Color and Weave projects. The straight-draw threading remains the same, just maintain the warp color order as you thread. And then follow the weft color sequence, also treadling for plain weave.

For example, the Color and Weave Towels are warped with an 11-thread repeat of 3 Dark, 1 Light, 3 Dark, 4 Light, which would look like this on a 4-shaft loom:

Read right to left; threading is one full repeat plus the first 9 of the second repeat

The treadling would follow the plain weave (1-3, 2-4) sequence in the weft color order (3 Dark, 1 Light, 1 Dark, 1 Light, 1 Dark, 1 Light). 


One potential variation to this rule would be the Running Stitch projects, which are threaded and treadled with the accent color doubled, but treated as a single end. You could thread both ends through the same heddle and same dent in your reed, or you could thread each end through two adjacent heddles on the same shaft and sleyed through the same dent in your reed. If you choose the latter you would still have a straight draw threading, but there would be two heddles on the accent color shafts, as follows:

The treadling would be as warpedthe Main Color in alternating plain weave sheds, both picks of the Accent color in the same shed (you’ll want to use a floating selvedge). 

Converting Weft Float Structures

If you want to weave a float-based rigid heddle project on a shaft loom, the key is figuring out the pattern shed(s) relative to the plain weave sheds.

Let’s use the Rigid Heddle Overshot Towels as an example. This project uses a pick up stick to raise every other slot thread. Because each slot thread has a paired hole thread, picking up every other slot thread creates a weft float that travels over 3 warp threads (1 hole, 1 slot, then another hole thread) then under 1 (raised slot thread). The weaving sequence is a pattern pick followed by a plain weave (or tabby) pick. So how do we recreate this on a shaft loom?

Since this pattern is columns of stacked floats alternating with a tabby pick, we can thread for plain weave and tie up for our tabby treadling. Now we just have to create a pattern shed that will allow the weft to travel over 3 warp ends and under 1. Since there are 4 shafts, that means we simply have to lift one shaft to make the same pattern shed as the pick up stick did on the rigid heddle loom. Let’s draft it out:

Here we have a straight-draw threading, with the tabby tie up and each shaft connected to one treadle. Raising only shaft 1 means the weft travels over the threads on shafts 2, 3, and 4. Raising shaft 2 means the weft travels over 1, 3 and 4, and so on. And there you have it—columns of stacked weft floats that travel over 3 warp threads.

Now, does it matter which shaft you raise for the pattern shed? Depending on which shafts you start and end your threading may determine which shaft you wish to use as your pattern shed. In the top and bottom blocks we can see if we raise only shaft 1 or 4 for the pattern, we will end up warp floats at one selvedge or another. If we raise only shafts 2 or 3 (middle blocks) we will get narrow tabby selvedges.

So think about how you want your edges to look and experiment with different shafts for your pattern. And remember that while the Overshot Towel pattern done on the rigid heddle loom utilized only stacked floats (offset floats would have required changing pick up sticks or using a heddle rod), a shaft loom gives the weaver the flexibility to stagger the floats by changing the pattern shaft.

 

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