For those of you who want to buy a cloth beam, not make or commission one, a different style of cloth beam is listed for sale on the Lacis website. It is called a backstrap horse bar, and it looks very similar to a drawing of an Algerian and Moroccan-style cloth beam in Peter Collingwood's The Techniques of Tablet Weaving. It should function just as well as this one.
You can use the information in this post, the dimensions, for personal and commercial purposes. Make a cloth beam, sell a cloth beam, commission your favourite woodworker to make you a cloth beam. Just don't pass off the design as your own or the wording of this blog post as your own. I have no idea who designed the tool, and I don't even know if I have interpreted the film image correctly. I paused the film, measured the image of the tool, and scaled it up using another object in the picture to guess at the size. I make no guarantees about your final product. All I can say is the reproductions I have of Seledkova's cloth beam work.
Here are two views of a cloth beam my father made for me. Click to see a larger photo. The wood would look prettier with more sanding but it works perfectly well like this.
This is what my father has to say about construction:
Use a good, straight grained hardwood, and ensure that it is the proper thickness. Cut it by ripping it into the required width, crosscut into the necessary lengths, and sand all the parts smooth. Then glue and clamp the cross bars to the long pieces. When dry, use an electric drill to drill and countersink for 1 1/2 inch #6 Robertson screws. Install the screws, then either round over all the edges using sandpaper, or use a roundover bit in a router. Finish sand.I asked him for a way to avoid visible screws, so that the tool could be used by historical re-enactors without drawing attention to its modern construction.
This could be done using hand tools, including a rip saw. Alternatively, purchase already dimensioned pieces and assemble them yourself. Commercially-available dowels would work, although you'd need to carve the cross piece ends to match the long side piece of dowel. Not at all hard to do if you have a sharp knife. Should take just a few minutes per joint. The screws are the key to a solid tool.
If you can sink the screw heads deeply enough, it is possible to insert a wooden plug (purchased or home cut using a plug cutter), but these pieces of wood are quite small to allow the 3/8 inch plug hole. You can use the same wood or a contrasting wood for an interesting effect.
If I were trying to avoid screws at all costs, I'd just glue the two pieces together (using traditional Medieval epoxy glue for strength, because the end of the cross piece is end grain and end grain doesn't glue well) and then drill a hole through the side and into the cross piece and drive in a glued wooden pin....If you do try to insert pins into glued holes, the glue will fill the hole and the pin will not be able to be inserted (you cannot compress a liquid, as you know) unless you provide a small groove on the pins for the glue to come out.Alternatively, a re-enactor could glue a strip of leather over top of the screws to hide them. As for whether the tool is authentic for a historical period, I can't tell you. The 1981 film shows an elderly weaver, Seledkova, a member of a traditional culture who says that she emigrated from Russia during the Russian Revolution to China, then to Brazil after China's 1949 revolution, then to Oregon. She says that she learned to weave belts before she left Russia and her people made belts when they were in China. If she learned to weave with the same style of cloth beam, the design could be a hundred years old or older. However, for all I know, the cloth beam's design could be only thirty years old and American in origin.
Please take all safety precautions when working with wood.
The best way to learn to use the cloth beam is to watch Seledkova in the film, though she doesn't set up the warp. I figured out how to do that by watching someone warp a rigid heddle loom and by reading books.
You may also be interested in my post, "How to Make Inexpensive Cards for Tablet Weaving."