Barn looms have similar features of course, but they also have slight variations on some features. This includes the warp beam.
Warp beams are seated at the back of the loom usually about four feet from the floor, and are designed to rotate to allow for the beaming of the warp, then rotate in the opposite direction as the warp is advanced throughout the weaving process. This does not vary.
What does vary are : the size, weight, circumferance, type of wood, placement of the beam, brake features, and shape. As nearly as I have been able to tell it is simply a matter of what the builder had in mind at the time the loom was made. Some looms, being made for specific types of weaving clearly had specific features to aid in that job.
The most basic warp beam is about 5 feet long give or take a few inches, is round, entirely made of wood, through and through, has ends carved from the beam into posts designed to rest in brackets fitted into the back of the rear support posts, and often has pegs inserted into holes in the beam itself that hold the cord for the tie-on rod.
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