| Sett calculator use
The sett calculator uses three variables to estimate the sett based on your yarn and draft. It works based on the following assumptions:
Here is how to use the calculator. It uses the following formula:
- The weaver is striving for a balanced weave
- The warp and weft yarns are similar in size
- There is little variation in the size of the yarns. (See below for a way to use the calculator when using warp yarns of varying weight).
S = (T * R) / (I + R)
S = the estimated Sett
T = the number of wraps of your yarn in an inch.
R = the number of ends in a repeat. You can get this from your draft.
I = the number of intersections in a repeat. This interaction of the number of ends to the number of intersections is the factor that allows you to estimate the density needed to have a fabric that drapes and isn't too dense or sleazy.
To see the number of intersections, look again at your draft. Using simple structures to demonstrate, plain weave has a one to one relationship - so there are two warp ends in a repeat and two intersections with a weft thread. A 2/1 twill has 3 ends in a repeat and two intersections.
- If you have never done this, you should practice first with a yarn that you know the plain weave sett. Typically, you will get a good plain weave if you take the wraps per inch divided by 2.When you are wrapping your inch - wrap at least two for a better result. If you are mixing warp yarns, wrap at least 3 inches of the yarns in proportion to their use in your warp. However much you wrap, don't forget to divide the results so that you get the epi not ep2(or3)i!
- If your structure is mixed and includes areas of plain weave through out, use the plain weave sett. For lace weaves, you'll also typically use the plain weave sett.
- Sample the results. This calculator provides an estimate - a place to start. The results depend on the materials you are using and the desired hand and drape of your end product.
Thanks to Sharon Alderman for giving us permission to use the sett formula, tips and thoughts from her book, Mastering Weave Structures: Turning Ideas into Great Cloth. Sharon acknowledges that this formula predates the publication of her book by several decades. However, Sharon has revised the process to include consideration of mixed warps, upholstery fabric, slippery yarns, and other special warps, thus giving the weaver a better understanding of the formula and how it can be used.