Wednesday, July 11, 2007

Warping the Glimakra: Adjusting the Shed

By Leigh

OK. My warp is wound on. I've threaded the heddles and sleyed the reed. I've tied up the treadles, (twice). Now I'm ready to weave! Well, almost. What I need to do next is check the shed and adjust it.

First of all, please excuse my photos of the shed. When I took them, my usual helpers were quite useless ........

Two lazy cats.So I simply held out the camera, pointed it at the shed, and clicked the shutter while standing at the front of the loom as I depressed the treadles. I managed to get a couple of photos to illustrate what I'm talking about.

To begin the evaluation, I first wove a few inches of plain weave. Then I checked the shed. Here is what it looked like at first:

Example of a poor shedIf you examine the bottom of the shed at the reed on the left, you can see that the warp ends pass through the reed at various heights. Looking down the length of the shed they all appear the same height, but in fact they are are all at different heights for the full 352 ends. No good. The shuttle will catch on some of these and pass under them when it is supposed to go over. That messes up the pattern on the cloth, which would obviously be frustrating. So the threads in the shed need to be adjusted.

I wouldn't have had a clue how to adjust the shed if it hadn't been for Joanne Hall's Tying Up the Countermarch Loom (more on that book in another post.) Here is what I learned about adjusting the shed.

Overhead jacks with locking pins in place.All adjustments on a countermarche loom start at the top. The loom comes equipped with removable locking pins, pictured in the locking position on the left. These lock the jacks in place so that the shafts stay put during adjustments.

Starting at the top, I checked to make sure that the shafts were centered to the loom. On a countemarche loom, the warp should run through the center of the heddle eye. If it doesn't, then the shafts need to be raised or lowered accordingly. The shafts are attacked to the overhead jacks with Texsolv cord and anchor pins. By adjusting the cord on the anchor pins (at the far ends of the jacks), the shafts can be raised or lowered.

I also checked the beater height, to make sure that the shed formed in the middle of the reed. You can see from the above shed photo that it does.

Next I checked to make sure that the lamms were level with one another.

Once I was satisfied that all was well so far, I removed the locking pins and started checking the treadles. To make sure the treadles are tied correctly, I pressed each treadle in turn and examined the shed. I noted which warp ends ran above the rest of the shed and made a list of which shafts these were connected to. I also made a list for the warp ends which ran below the rest of the shed.

It was from these lists that the treadle tie-up is adjusted. I took the treadles one at a time and started with the upper lamms (which lower the shed):

* For shafts with warp threads which were too high and ran above the shed, the treadle ties were shortened.

* For shafts with warp ends which were below the shed, the treadle ties were lengthened.

I repeated this for each treadle in turn. Then I checked the shed again and made further adjustments as needed.

This is what it looked like when I got done:

Example of a good bottom shed.The top of the shed still needs some adjustment, but the bottom is exactly the way it should be. To adjust the top of the shed, the treadle ties to the lower, lifting lamms are adjusted:

* For shafts with warp threads which were too high and ran above the shed, the treadle ties were lengthened.

* For shafts with warp ends which were below the shed, the treadle ties were shortened.

Note that this is the opposite of what was done with the upper lamms.

What a difference this made with my weaving! I used to have frequent skipped or caught warp threads with my other loom, but there have been very few so far this time. I cannot say that my shed was absolutely perfect for each treadle, but my goal is to improve my shed with each project.

To be honest, this was simply a "monkey see, monkey do" activity. I just followed the directions without understanding why they worked and got the results I needed. At this point I cannot look at the shed and automatically know what needs to be done to fix it and why. That is one of those things that will come with experience. Still, it feels good to be on the right track.

Now on to the weaving .........and at last Blanket Done!

Posted 11 July 2007 at

Related posts:
New Loom
Why A Countermarche?
Warping the Glimakra:
.....Adjusting the Loom With Texsolv
.....Winding On the Warp
.....Tying Up the Treadles
.....The 3 Duhs
.....Blanket Done!


Susan B. said...

It sure seems complicated! but well worth the promise of smooth weaving.
Happy weaving!

Amby said...

352 ends! I guess I'll stop whining about warping 140 ends on my little rigid heddle!

Can't wait to see the weaving!

Laritza said...

Looks great! Thanks for the easy to follow: short and long treadle adjusting.

Peg in South Carolina said...

My loom (a jack) has rear-hinged treadles with treadle springs, so I can make similar adjustments, though not quite as refined. But I never know whether to shorten or lengthen. Now I know! Thanks!

Kathy said...

Leigh, if I ever get a loom like this one, I will sure know who to go to for help and advice! I had forgotten how tricky some of these things could be with the countermarche. But then, if I get a bigger loom we'd have to move. Heeheehee! :)
Thanks for taking all the time to 'splain things to all of us, too. I can sure tell that you're having fun, even if it feels like your re-inventing the wheel.

Dorothy said...

Super photos and description of how you adjusted the ties for a good shed, I'm making a note of this methodical adjustment process and will refer to it next time I'm weaving. Thank you!

I'm now looking forward to seeing how your blanket turns out. I get the feeling you're going to have a good relationship with this loom.


Donna said...

Great job, as usual, Talented Twin! Waiting for the next installment in this adventure is keeping me on the edge of my chair. Like a really good book, can't put it down. Speaking of books, can you recommend Joanne Hall's on tying the countermarche loom?

Having just completed reweaving the skips in a shawl fresh off my jack loom makes me all the more anxious to do what you're doing. And, you are leaving a wonderous trail for all of us to follow. Thank You!!

Cathy said...

Wow - how wonderful that you can make those adjustments, and what a great job you've done!

Leigh said...

Well, ya'll. I'm very relieved to know that I was able to explain this in a way that made sense. Thank you for the encouraging feedback. I had to re-read the instructions for each treadle, but I know that eventually this will become 2nd nature to me.

Dorothy, I really like this loom in spite of the initial frustrations so I plan a very long life together!

Donna, Joanne Hall's book is an excellent introduction to tying up CM looms. I should have gotten it before I put my loom together. I will blog a little more about this book soon.

Sharon said...

My dear weaving friend in Oregon has a CM loom and from her I know that when you've fine tuned, you'll be so there. She brags about the size of the open shed. As a spinner, I switched from double drive to scotch tension for the fine changes I can make and I think that's the kind of experience you'll have with the CM shed. You'll be able to fine tune where us jack-loom folks will have the shed the loom gives and no more.

Downshiftingpath said...

Leigh, your posts are always interesting and informative. I learn a lot from them. Glad you can fix these things and show us how.

Annie said...

Wow, and I thought it was normal that my shed was all uneven. I have a different type of loom, (LeClerc 4 shaft) but now I am going to poke around and see if I can even things out a bit! Thanks! :-)

Anonymous said...

Leigh - your patience is fantastic. Well done!

Anonymous said...

Ive just woven my first piece and it was fantastic to discover this post. I am not clear about adjusting my Bergman but you have definately helped. I hadn't made the connection between treadles and sheds. Deborahbee

Leigh said...

Deborahbee, congratulations on your first piece and thank you for your kind comment. I agree that adjusting the shed isn't easy and I admit that I sometimes still have some trouble.

The relationship of the treadles and sheds has to do with how evenly the treadles open the shafts to make the bottom of the shed. If some threads on the bottom of the shed are too high, then the treadle isn't pulling the shaft down far enough. If some of the threads are too low, then they are being pulled down too far. What makes it even more confusing is trying to figure out which lamm ties to adjust - the shorter (to adjust the bottom of the shed) or the longer ones (to adjust the top of the shed)!

I can't recommend Joanne Hall's book, Tying Up the Countermarch Loom enough. If you don't have it yet, it's an excellent resource. It's available on her website, Elkhorn Mountain Weaving.

LisaCothronLaw said...

Thanks for this! I needed this detailed bit of information to help with my new CM.