live weight tensioning
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Penny Lacroix
Hello! Thanks for adding me! I'm going to dive right in here. I've searched the archives for info on live weight tensioning and still have some questions. It's nice to see that Kati Meek is on this group! In Kati's book on page 27, it says that "the amount of weight needed depends on a variety of factors." I have tried to use the system weaving Kati describes for an overshot coverlet on my barn frame loom. Here are the variables, as indicated in Kati's book:
When I tried it, I put a total of 60 lbs of weight, 30 lbs on each end of the beam, and still there was not enough tension to beat properly. (I think the counter weights were 1 or 2 lbs on each side.) So here are the questions:
Any additional advice or experience sharing would be appreciated! Happy weaving! - Penny Lacroix |
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Chuck Colht
You can increase the "torque" of the weight by increasing the diameter of the pulley the weight hangs from. On Mon, Nov 8, 2021, 8:00 AM Penny Lacroix <weaver39@...> wrote:
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Penny Lacroix
So, Chuck, the fact that my warp beam is so large should work in my favor and would mean less weight is needed. But "less" is a relative term. - Penny from my phone On Mon, Nov 8, 2021, 12:33 PM Chuck Colht <chuck@...> wrote:
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Janell Neulinger
I can’t find one now but I sure I have seen woodcuts of barn looms with the warp beam weighted with a trough filled with rocks. I would just try adding more weight - it’s not like you are going to break your warp threads if you are still at lower tension than you’d use with a ratchet & pawl. The June 2021 Complex Weavers has an article on measuring warp tension that might help - you can measure how you like the tension to be with your usual tensioning system and predict how much weight you’ll need to get the same with live-weight
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Jayne F
It’s not about the amount of weight per se, it’s about the amount of friction between the rope wraps and the beam. A “hard” rope will not have as much contact with the beam as a soft one, which will flatten. Some types of rope are more slippery than others. More turns around the beam will provide more friction. Just some things to think about. Jayne
From: weavetech@groups.io [mailto:weavetech@groups.io] On Behalf Of Janell Neulinger
I can’t find one now but I sure I have seen woodcuts of barn looms with the warp beam weighted with a trough filled with rocks. I would just try adding more weight - it’s not like you are going to break your warp threads if you are still at lower tension than you’d use with a ratchet & pawl. The June 2021 Complex Weavers has an article on measuring warp tension that might help - you can measure how you like the tension to be with your usual tensioning system and predict how much weight you’ll need to get the same with live-weight
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Sara von Tresckow
Ms. Lacroix,
Live tension is just a practical application of Euler’s capstan formula F1 = F2 x e to the power of (my x alpha) where F1 is your warp force; F2 is the live tension weight; e is the Euler constant = 2.71828; my = friction factor between rope or wire and wooden beam; alpha = wrapping angle around beam in radiant- one wrap = 2 x pi. With out understanding what I just wrote you can increase F1 either by increasing F2 or increasing the wraps around the warp beam or change the friction coefficient by roughing the warp beam at the brake site with coarse emery cloth or using different material for the brake to increase the friction between brake and warp beam.
Hans von Tresckow
From: weavetech@groups.io <weavetech@groups.io> On Behalf Of Penny Lacroix
Sent: Monday, November 8, 2021 10:07 AM To: weavetech@groups.io Subject: [weavetech] live weight tensioning
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Joe P
Hi Everyone
If you are looking for pictures of wood weight box and diagram. Hand Weaving and Cloth Design by Marianne Straub page 23. The set up is not shown on barn loom. Shown on George Wood Loom. When I want to see something done I check out you tube videos. Type in to your search (you tube live weight tension on floor loom) The first video that comes is is one done by Kati M. I think you will enjoy seeing the video Keep Weaving Joe Bear in WI U.S.A. |
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Syne Mitchell
I found that changing the rope I was using to one with more "tooth" made the difference in my live tension system. Along with the other methods of increasing friction Hans mentioned above. I'm playing around with a live tension system at the moment as well, and one discovery was that having it balanced on both sides of the warp beam (instead of one side) is a good idea. :) On Mon, Nov 8, 2021 at 2:57 PM Joe P <rugsbyjoe@...> wrote: Hi Everyone |
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Penny Lacroix
Hans, thanks for the explanation of the physics. That makes sense. Syne, can you elaborate on your choice of ropes? What has worked the best for you? What has not worked? Kati's book calls for "braided cotton cord". I'm thinking this is the stuff you get in the clothesline section of the hardware store? It comes in different sizes. Have you tried this or something else? In my trial, I used strapping that we use to attach our canoe to the car roof. It is wide with convenient hooks on the ends, but maybe more slippery than it should be, even if wrapped several times. - Penny On Tue, Nov 9, 2021, 12:46 AM Syne Mitchell <synemitchell@...> wrote:
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Isabelle Fusey
In addition to the illustration mentioned earlier on page page 23 of Weaving and Cloth Design by Marianne Straub, you can see an illustration of a weighted box on page 105 in Ideas in Weaving by Anne Sutton/Diane Sheehan. There is also a short description of how to set up a weight box page 60 of The Technique of Weaving by John Tovey.
Isabelle |
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Sally O
 Here is a photo of the live weight tensioning system on one of the silk looms in Sweden. |
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Syne Mitchell
Very cool! Thanks for sharing that image. On Tue, Nov 16, 2021 at 8:37 AM Sally O <s.orgren@...> wrote:
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Penny Lacroix
Thanks, Sally! I will let you know how it works! - Penny from my phone On Wed, Nov 17, 2021, 4:13 AM Syne Mitchell <synemitchell@...> wrote:
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DR D W Taylor
In case you haven’t seen…Tien Chiu also has great info about live tensioning on her website. There are great pictures and explanations
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Do you think they alter the weight on the system by putting different weights in that hanging box?
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Sara von Tresckow
Of course those weights are altered. If you visit any European weaving
studio where live weight is in play, there will be an eclectic collection of loom weights sitting near the loom - field stones, cast iron scale weights, bricks - that is the beauty of the system. Once the tension is established, it works almost as well as a technically sophisticated auto advance. Sara von Tresckow, Fond du Lac, WI sarav@... Author of “When a Single Harness Simply Isn’t Enough” http://www.woolgatherers.com Dutch Master Loom/Spinning Chairs/Öxabäck Looms, visit us in Fond du Lac or contact us about your weaving/spinning needs |
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