Since I have only woven one shawl (one third of the warp) I'm only saying that the collar is looking promising. In order to determine if it is going to work the way I want it to, I need to finish this warp and see if it works well, right to the very end. I also need to put another warp on that requires higher tension. With a special order of six place mats needing to go on as soon as these shawls are complete, I should know fairly soon.
When I looked at photos of older looms with the live weight tension system, they all seemed to have this much larger diameter collar for the cord to run around. I think it is because a better ratio between where the cord is holding tension and the diameter of the warp is required.
The larger collar accomplishes a couple of things. One, it's round, not hexagonal so the cord has a smooth surface to slip on, not the hexagonal planes of the beam. Two, the much larger diameter means the cord has a lot more surface to grip and I think that is why so much less weight is needed.
With the cord just wrapped around the beam, I was using 3 pounds on the 'light' end of the cord, 25 pounds on the 'heavy' end. With the collar, I've got 3 pounds on the 'light' end, but just 13 pounds on the heavy end. The result? Less effort required to advance the warp.
I'm sure my neck/shoulder will thank me!
But I need to finish this warp and see how the tension holds right from the beginning to the end. Plus how it works on a warp requiring much higher tension. The collar is actually larger than the diameter of the shawl warp which is 9 meters long, so it should allow my maximum warp length of 11 meters with no problems.