Unbalanced yarns can cause twists within the raddle groups. Singles, novelties, some linens, and some handspun yarns are often unbalanced. Even if they appear balanced, give them the hot water test to be sure. Remember, plied yarns can be unbalanced as well as singles.
Problems caused by unbalanced yarns
Sometimes during beaming, severe twists occur within the raddle groups–as though all the yarns wrap around themselves within each raddle group. These unbalanced yarns are doing what they naturally tend to do–roll around each other. See illustration. They must not be allowed to twist like this as they are wound onto the warp beam. If they are twisted on the warp beam, the warp cannot be woven unless drastic remedies are taken.
Watch the raddle groups as you’re beaming to be sure this isn’t happening. There is more of a chance for the yarns to twist the farther away the raddle is from the warp beam. Say, if the raddle is on the castle.
Having fewer warps in each group helps, too, but isn’t enough when the yarn is very unbalanced.
It’s a good idea to check if the yarn is unbalanced before you begin your project. You can take some precautions when you know you have a troublesome yarn and beam with the thread-by-thread lease sticks in. Place them between the raddle and the warp beam (like the Swedes do) or between the castle and the raddle. Using slippery cord for a lease cord works if your lease sticks aren’t perfectly smooth. You might make both leases at one end of the warp on the warping board or use a counting string to separate the raddle groups. During beaming, the warp passes through both the lease and the raddle. It is very important that the threads go perfectly in order from the lease sticks to the warp beam. Any twists here may cause severe raddle twists–what you’re trying to avoid! Take the time now and use your fingers to line up each and every thread.
What if the twists go un-noticed until after the warp is threaded?
I’ve noticed this problem after the warp is beamed, threaded, sleyed in the reed, and tied onto the cloth apron rod or not until several inches have been woven. Here are two solutions. They both are tedious and much easier if you have a helper.
One is to put lease sticks behind the heddles (treadle the sheds to make the lease) and carefully unroll the warp from the warp beam and wind it up on the cloth beam, working the lease sticks back toward the warp beam as far as you can. If your helper is at the back and you’re at the front, it helps. You won’t be able to work the sticks all the way back to the apron rod because of the twists. That means you’ll lose that much of the warp.
The other solution is to unroll the warp beam, pulling the warp forward to the front of the loom. Wind the warp up temporarily on a kite stick to avoid tangling. When all the warp is unrolled, begin the beaming process again. This time the reed will act like a raddle and spread out the warps and prevent twists.
Take your time re-beaming. The threads will be closer together in the reed and in the heddles so there is more chance for breakage than when the warp was in the raddle.
Taken from Books 2 and 3 and Weaving for Beginners