Uneven Warp Threads
I hope you can help me. I found your warping video very helpful; I especially enjoyed the tip about raising the loom to be able to thread the heddles. However, when it comes time to tie on the warp threads at the front, I consistently get a diagonal line of threads, with the threads on one side being shorter than the other. Does that make sense? Is this because somehow the warp threads are getting tighter as I wind on to the warping frame?
That could be one explanation, that you are winding more and more tightly as you wind the warp on the warping board. You should wind on the warp in a loose, relaxed sort of way. The threads should not sag, but they should not be pulled tightly. If you wind them on tightly, you could actually be bending the pegs inward slightly as you wind and push the threads to the back of the board. The last threads you wind will therefore go through a shorter distance around the board.
There could be something else going on, though. I'm assuming that you don't notice the difference until you have finished winding the warp on the warp beam and you are ready to tie onto the front apron rod. The difference in warp length at that point could be related to the method you use to tension the warp on the warp beam. Some people hold the warp with one hand and turn the beam with the other, using the holding hand to control the tension that the warp is under as it goes on the beam. This can cause torque on the beam, so that the threads on the end of the beam closest to the turning crank go on at a smaller circumference than those at the opposite end of the beam. If you tension the warp as I show in the video (pulling firmly on small sections at the front after a turn or so of the beam with no tension applied as you turn the beam), this shouldn't happen. When you pull on the warp groups, it is good to change the order in which you pull, starting at the left one time, the right the next time, from the center out the third time, and then repeat. If you always start at the same side, you could get a difference in warp length such as you describe, with the starting or ending side being pulled more tightly than the opposite (you might pull more or less firmly as you go from group to group).
You can assess what's going on by examining which threads are shorter or longer (where are the threads on the warping board that turn out to be shorter or longer; where are they in relation to the crank side of the warp beam, where are they in relation to your method of tensioning). Please do let me know what you do discover to be the cause! I especially love the problem-solving aspect of weaving.