Dealing with the Diagonal of the Weft

Place the weft in the shed on a diagonal as shown in the illustration. Every beginning weaver knows this and that it is very important. The reason for the diagonal is to put some extra slack into the weft, making each weft a bit longer than the actual width of the warp. Because the wefts are forced to bend over the warps during weaving, extra slack in the wefts is imperative. In fact, some weave structures require even more slack. Read the post about bubbling dated January 16, 2023 HERE.

You can’t see this phenomenon while at the loom because the warps are under tension and are straight when the sheds are made. It’s not until after the cloth is off the loom that you can see that the wefts are bending (the warps may, too). Because the wefts are forced to bend over the warps during weaving, extra slack in the wefts is imperative.

This illustration shows in cross section even more dramatically how the wefts bend over and under the warps.

Ideally, a diagonal should form naturally from the edge of the woven cloth (the fell) to the shuttle race. The shuttle race is the ledge on the beater at the base of the reed where the shuttle rides in the shed. Most, but not all, looms have a shuttle race. Ideally, it is all the diagonal that is needed. Read about how much diagonal is necessary below.

The natural movement might be to swing the arm back, pulling the weft in an arc down to the fell of the cloth. This shape doesn’t allow enough slack in the weft and will cause the cloth to narrow in.

How much diagonal?
If you don’t put in enough slack, the cloth will draw in too much. This is a huge problem (called draw-in) and is to be avoided at all costs.

If you put too much diagonal in, weft loops at the selvedges will form and/or little loops will form in the cloth.

The diagonal is just right if the cloth draws in only a tiny bit at each selvedge, say, ¼” or less.

How to place the weft at the selvedge
Snug up the weft against the outside warp thread—neither pulling that selvedge thread in, nor leaving a loop on the outside of it. I like to snug the weft up until it barely moves that outside selvedge thread—just grazes it. The wefts should turn around neatly against the selvedges.

Don’t touch the selvedges. You can control the weft at the selvedges with your shuttle. Touching the selvedges is a bad habit—it can slow you down and prevent an even rhythm, which is an important aspect of making good looking selvedge.

What if the Selvedges Splay Out?
If your outside selvedge threads begin to splay out as shown here, there is too much angle in the diagonal of the weft. You must stop this or the wefts will just continue to splay out more and more.

To correct this problem, throw the next weft, and while it is still loose in the shed, tug the previous weft at the selvedge, pulling out the tiny bit of excess weft.

Then, take up that extra weft in the new shed and beat it in as usual. The tiny bit of slack that is taken out will straighten the warps. When the selvedges are back in place, decrease the angle of the diagonal in your wefts. You should need to make this adjustment only a few times to get the selvedges back in place. One way to decrease the angle is to move the fell of the cloth a little closer to the reed.

12 thoughts on “Dealing with the Diagonal of the Weft”

  1. Interesting article. In weaving class, I was told to allow a little extra weft at the selvedge & lay the weft at a diagonal. After beating, it snugs up to the selvedge. Is this wrong?

    • If you have good selvedges with this sequence that’s all that matters. You are getting the right amount of weft in. Keep this post in case you have selvedge problems in the future. Or, know that everything was taken from my book Weaving for Beginners. My books are available on my website,


    • Marlie, I admire your selvedges every day. If you want more info there is a chapter on selvedges in my Weaving for Beginners where I try to explain many details. Also another chapter on trouble shooting. I don’t want you to struggle–be careful and know what you are doing is my goal. Another thing my mentor Jim Ahrens said: “the best selvedges come when you don’t pay any attention to them.” Peggy

  2. Thank you, Peggy! I learned to make an arc (RHL) and carried it over to loom knitting. This is excellent information that has helped me to identify why my sides are sometimes great and sometimes not.

  3. Thank you! Even though I knew about making my weft go in on the diagonal, your explanation helped me understand why and how to correct a selvedge weft bubble.

  4. Thank you Peggy for the reminders. Still learning and weaving on my F J Ahrens 8 shaft 10 treadle! Most learning now is by making mistakes. 😊. Liz Fisher

  5. Thank you for all these lessons, I have your books, but find these a great reminder, especially when I’m not getting the results I want.


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