2/1 Twill: First attempt

Back here I started talking about my attempts to weave twill on a rigid heddle loom, using two heddles.

So, I have a threading that results in three sets of threads:

  • one goes through the holes on the back heddle and the slots on the front heddle
  • one goes through the slots on the back heddle and the holes slots on the front heddle
  • one goes through the the slots on both the front and back heddles

To weave a simple twill, each set of threads must be lifted (or dropped) in turn.  Notice that on a rigid heddle loom, you have the option of creating either a rising shed (threads in holes are lifted above the neutral threads) or a sinking shed (threads in holes are pushed below the neutral threads).

The order I came up with was as follows:

  1. back heddle up, front heddle down, weave in rising shed
  2. front heddle up, back heddle down, weave in rising shed
  3. both heddles down, weave in sinking shed

**Theoretically** this works.  The crucial problem with my scheme, as described, though, is that in steps one and two, no heddle should be *down* but, rather, in neutral.  Otherwise, you get:

  • tension issues
  • one shed is wrong; thread from rear heddle gets blocked by front heddle and deflected.

Resulting fabric is pretty, but not a twill…

2/1 Twill: Getting started

A while back, I posted about the possibility of doing a simple twill on a rigid heddle loom with two heddles (the original post is here).  I never did try a two-heddle tabby, just launched straight in to attempting the twill.  Perhaps, if I had tried the tabby first, I would have ironed out a couple of the issues I had initially, but then again, I might not.

A 2/1 twill has weft threads that go over two warps, then under one and so on (or over one and under two – depending on which side you look at).  Each row, the pattern is offset by one warp end, so you get the diagonal lines typical of simple twill fabrics – look at regular denim for a good example, or the following diagram as an alternative:
Twilldiagram

To weave a 2/1 twill on a rigid heddle loom, you need either to use pick-up sticks or two heddles.  I’m using two heddles.  This way, I can thread three warp thread paths:

  • one goes through the holes on the back heddle and the slots on the front (red)
  • one goes through the slots on the back heddle and the holes slots on the front (green)
  • one goes through the the slots on both the front and back heddles (blue)

21_threading

Or that’s the theory, anyway.  Notice that you get THREE ends per dent in this threading, instead of the usual two.  My yarn worked out at 19wpi, so using the handy-dandy calculator from The Weaver’s Companion, I worked out that I should be looking at a sett of about 11 to 12 epi.  That means a 7.5 dent heddle is about perfect (11.5 divided by 1.5 is 7.6).

But I don’t have two 7.5 dent heddles.  I do have a 7.5 and a 15, though, and the astute will note that 7.5 is half of 15.  So my threading now looks something like this:

21_threadingspaced_2

my original plan was to talk about the actual weaving of this piece tonight, but I reckon this post is long enough already – it’s certainly taken long enough to write! – so I’ll have to save that for another day…