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Wednesday, September 16, 2009

A Simplified Tie-Up for Double Countermarch Looms

That's the title of the original article by Peter Collingwood. I'm assuming that the "double" in the title refers to the fact that there are two sets of lamms: risers and sinkers.

I'll scan the copy of the article and put it on my website later, and will post here when it's in place.

On a conventional countermarche loom, each treadle is tied to every shaft, either via the shaft's rising lamm OR its sinking lamm. So each treadle has as many cords connected as there are shafts. (We're talking conventional tie-up here, not a skeleton tie-up that requires the weaver to press two treadles to get the desired shed.)

With the "simplified" tie-up, the treadle has two cords for each shaft. One cord is tied to the rising lamm and the other to the sinking lamm. The two cords go from their respective lamms down through an eye-bolt on the treadle, back under a metal rod added to the loom above and parallel to the treadle pivot point, then up through holes in a board added to the back of the loom.

On that board, there is a column of paired holes for each treadle. We implemented it like this:



The cord that came from shaft 1's sinking lamm goes through the topmost left-hand hole; the cord from shaft 1's rising lamm goes through the topmost right-hand hole. And so on down the shafts.

Let's say I want shaft 1 to rise and shaft 2 to sink. I pull the right cord for shaft 1 taut, pull the left cord for shaft 2 taut, wind them around the wingnut, and tighten the wingnut so both cords are held securely. The unused cords for those shafts are left slack. I continue on, tightening the appropriate left or right cords for each shaft.

If I had used texsolv cord, I could just plug a standard white plastic texsolv pin into the appropriate opening in the cord. However, texsolv cording for this project was outrageously expensive compared to the ordinary braided nylon cord available at the hardware store, so we went with the wingnuts and saved $$$.

Keep in mind that you need about 2 yards of cord per shaft, times 2, times the number of treadles. So with 8 shafts and 10 treadles, I needed 320 yards of cord. The amount of cord required for each shaft is determined by the distance from the lamm to the treadle and out the back with some slack. My loom is an Ideal, the small-frame Glimakra. If you have a Standard Glimakra, the yardage requirement might well be more because the loom is deeper from front to back.

I still haven't woven enough with this tie-up system to be certain that it's superior to the conventional system, but anything that provides an ergonomic improvement from the perspective of the weaver's back is A Good Thing.

I do agree with Neki's comment that the best solution to the tie-up problem is, of course, a dobby loom :) But I'm biased.......

4 comments:

Sandra Rude said...

P.S. Texsolv cord is USD 1.50 per yard...

Susan Harvey said...

This plan was modified from Peter's and is now available for rear mounted treadles. I purchased this set up and have it mounted on my large CM loom. You can see it here:
http://weeverwoman.blogspot.com/2008/01/all-about-tie-up-assists.html

On my front page at the blog are a couple more links (under topic shopping) on the 20+

I absolutely love it! It saves my poor joints from being under the loom and tie up's are a breeze.

Susan

Life Looms Large said...

Interesting!! I'm very intrigued. Glad to hear that you're trying it with nylon, not Texsolv, because Texsolv does really add up.

Vavstuga does sell Texsolv for 90 cents a yard...but that still adds up fast!

I think I might be adding something like this to my Christmas list!!

Sue

Carmen Vincent said...

Thanks for these posts on warping methodology. They come at a good time. I have an 8 shaft Glimakra Standard. This will be interesting!