With the exception of warping a loom sectionally, we are taught a heavy paper or slats of some kind must be wound along with the warp to insure an even tension throughout the weaving process. Picture wrapping thread around a tube. No matter how careful you are, the thread forms a hump in the middle of your tube. The thread travels farther when it winds around the center, built up section than it does on the edges. If you wound your warp around the beam without heavy paper or slats, some threads would fall off the edge of the pile on each end and those threads would be shorter than the threads in the middle of the warp. You can imagine the problems the shorter threads would cause as you tried to weave.
There is another way to achieve the even tension necessary. Flanges are positioned on each side of the warp. A flange is a protruding rim or edge. Since the threads cannot spread out, the warp stacks up inside the flanges in an orderly fashion insuring all the warp ends are the same length. Picture winding thread on the bobbin you use in your boat shuttle. It is equipped with flanges on each end. The flanges keep the thread from falling off the ends of the bobbin and as the layers build up. Not exactly the same since the bobbin is wound with one thread and the warp beam is wound with many.
Many industry looms are equipped with flanges on the warp beam. When I did a search today, most of the sites I found regarding flanges/weaving were industrial. I have heard flanges mentioned for handweaving looms on the different weaving groups I participate in and have read one or two articles about flanges. This is the best reference I found regarding flanges for handweaving http://www.glimakrausa.com/faq.html The information on flanges is very close to the bottom of this very long and informative page.
On a sectional warp beam, the warp is wound around the beam in sections and held in place by the flanges of each section. This eliminates the need for paper or slats in the warping process. Another thing I believe helps is the circumference of the larger sectional beams. A yard of warp wraps around my large sectional beam one time instead of about 4 ½ times on the smaller standard beams I have used. So a ten yard warp wraps around the beam ten times instead of about forty five times.
February 23rd, 2008 at 11:01 am
Thanks. Sometimes it is funny how I assume a reason for something that is not the real reason at all. I wasn’t thinking about the threads on the ends falling off the edges and therefore being shorter, as you describe (which makes perfect sense). I had assumed it was to keep the yarns from burying themselves between others, causing similar problems. And I supposed that with threads falling off the ends, they could become less closely spaced and do that as well, but I had not realized the purpose of the flanges. It makes perfect sense that with the flanges to keep the end threads in place, all the others would also stay nicely in place. One of these days, perhaps I will try mine. Of course there is the thing about not wanting to put on very long warps that kind of keeps me from using it. But the towels for my friend are ready to be taken off the loom. I hope to get that accomplished today. Hurray!
February 23rd, 2008 at 12:05 pm
I always thought that too until I did a bit more research.
Yay! For finishing your towels! It feels good to finish a project.