New old loom for weaving tartan

[NHhighlander]

Doesn't look like much advance yesterday, but, one step at a time, Dad said.



Fundamental moving parts are in.

• A start of the beater frame - hanging from top
• B the pedals
• C the lams
• D the shafts (two sticks form one shaft, 8 sticks here)

Four shafts are needed for twill weaving.
Each pair of sticks holds a frame. Frame holds the heddles, each heddle carries one warp thread. We will need 628 heddles for 25 inches at 25 ppi (picks-per-inch, the density of the fabric. Lightweight tartan goes 40 ppi or more, this one is heavy, 22oz, did we say?), therefore 157 heddles in each shaft frame (these sticks here are mostly stand-in for sanity-check purposes, the good ones will be narrower. See https://www.youtube.com/watch?v=Ly-lFONTuGk. Again, one step at a time).
Shafts are paired two-by-two, hanging from pulleys on the structure on top. One shaft of each pair is pulled down, the corresponding pair gets pulled up. Let's call our shafts 1, 2, 3 and 4.
In "normal" floor looms, an ingenious system allows lifting any pair by the use of 6 pedals. This allows the choice to weave twill or plain weave. However, I do not care for plain weave, only twill, therefore I will need only 4 pedals, which also simplifies the pulley system (in previous looms that I have built, adjusting the pulleys gave me much grief and waste of time and happy. I'm looking forward to an easier life if I can - other people building looms have also reported regarding this being a sore point and challenge). Therefore, my pairs are 1::3, and 2::4. If you think about it, I can never lift 1 and 3 at the same time, one goes up, the opposite goes down.

The magic of twill comes together with a 4-step sequence.
Shafts 1 and 2 go down (3 and 4 are pulled up, obviously), one thread of weft goes though, get beaten in the fabric.
Follow by lifting 2 and 3 (3 went down, pulled its corresponding paired 1 up, 2 just waits there), shuttle returns, another thread, beat.
Then 3 and 4 down, thread.
4 and 1 and thread complete the sequence, which will then restart again with 1 and 2, etc.

4,500 times later (1,125 sequences of 4 steps), 180 inches of tartan are done, 5 yards for a box-pleated kilt (box pleating seems to be the right thing for heavy, "legacy" tartan, which uses less yardage). Oh yes, there is some shrinking to be compensated, during weaving, during post-weave washing, and also the sequence gets mighty funny the first and last few inches for the envisioned Total Border with herringbone and chevron and birdseye, but, as it is written, one problem at...

The way the whole assembly works, is that one set of shafts is attached to each lam. Because each pair of shafts happen to hang together from the pulleys, the lams are supposed to be, in order, 1, 3, 2, 4, for shaft pair 1::3 and 2::4. So far so good.

Then, each pedal is supposed to pull two shafts at the same time. That's where it all comes together. Starting from the left, the first pedal will pull lams 1 and 2, which will pull down their attached shafts, causing their paired ones to go up.
The next pedal will be set to pull lams 2 and 3. Etc.

We'll see at the end of day today...

Important disclaimer: my setup responds to my way of doing things. While I try to respect orthodox and time-honored procedure, as it works for others, I got way too confused trying to follow what other people say that they have been doing, and figured out by myself, using the honored process of error and fix, in finding something that WORKS. Solid, reliable. I cannot guarantee that this is what the rest of the world is doing. More so, I'm pretty sure it isn't, it appears that standard looms operate on a different arrangement of lams and shafts and pulleys oh my. But, if it works, then I'm happy. YMMV, etc.