Warp Yarn Calculation
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To be honest, I typically skip warp calculations all together unless I’m running out of the yarn I’m planning to use or the band I’m planning to weave is particularly long (more than 7 feet) or wide (more than 2.5”), because I typically use the same yarn I have from weaving, so I have more than enough yarn to do a band.
However, if you’re planning a project where you need a band of a particular length, one of the things you’ll need to take into account is how much yarn you’ll need for your warp. Inkle bands are typically warp faced so, you don’t have to worry about take up (the amount of length you lose as you weave) as much as you do with other forms of weaving, so warp calculations are a breeze. If you need your finished band to be a certain length, start with step 1. If the length doesn’t matter, you can skip to step 3.
Step 1: Determine your loom waste. Keep in mind that you will lose some length from your warp as loom waste which is shown in Figure 6 in blue. On an inkle loom, your loom waste depends on your warp path: you’ll lose at least the length between the top dowel closest to you (A) and the first turning point of the warp (B) plus the distance between that same dowel (A) and the point where weaving stops being comfortable (C) (for me that’s about 2 inches from the heddles on the Baby Grand, but it will vary from weaver to weaver). For the warp path pictured, I would plan to lose the length in blue. That’s 4.5” from A to B plus 6” from A to C which gives a minimum of 10.5” loom waste on the path shown. In other words, even though the warp path is 50” the weaving length on the band produced is 39.5” (not including fringe).
Note: On the Lofty Baby Grand the distance from A to B will either be 4.5” or 7.5” depending on whether you use the middle dowel on the top side. On the Lofty Grand the distance from A to B will vary depending on your chosen loom configuration and warp path.
Step 2: Calculate shrinkage (if applicable—really only if you plan to wet finish your band or if it will be laundered as a result of end use). In my experience linen and cotton bands have negligible shrinkage when wet finished. However, wool bands will shrink and possibly felt depending on the breed of sheep the yarn comes from, the twist of the yarn, and how the bands are washed. If the end use of your band will involve washing and your band will be made of a fiber that, like wool or rayon, will typically have a lot of shrinkage you will need to add length here. The best way to figure out the length to add is to weave a short sample band and then calculate as follows:
(1 - (length of wet finished band / length of band after weaving)) * 100 = Pct of Shrinkage
(𝑓𝑖𝑛𝑖𝑠ℎ𝑒𝑑 𝑙𝑒𝑛𝑔𝑡ℎ + 𝑙𝑜𝑜𝑚 𝑤𝑎𝑠𝑡𝑒) ∗ 𝑝𝑒𝑟𝑐𝑒𝑛𝑡 𝑜𝑓 𝑠ℎ𝑟𝑖𝑛𝑘𝑎𝑔𝑒 = 𝑎𝑚𝑜𝑢𝑛𝑡 𝑜𝑓 𝑒𝑥𝑝𝑒𝑐𝑡𝑒𝑑 𝑠ℎ𝑟𝑖𝑛𝑘𝑎𝑔𝑒
𝑓𝑖𝑛𝑖𝑠ℎ𝑒𝑑 𝑙𝑒𝑛𝑔𝑡ℎ + 𝑙𝑜𝑜𝑚 𝑤𝑎𝑠𝑡𝑒 + 𝑎𝑚𝑜𝑢𝑛𝑡 𝑜𝑓 𝑒𝑥𝑝𝑒𝑐𝑡𝑒𝑑 𝑠ℎ𝑟𝑖𝑛𝑘𝑎𝑔𝑒 = 𝑡𝑜𝑡𝑎𝑙 𝑚𝑖𝑛𝑖𝑚𝑢𝑚 𝑤𝑎𝑟𝑝 𝑙𝑒𝑛𝑔𝑡ℎ
Percent of Shrinkage
(1 - (length of wet finished band / length of band after weaving)) * 100
Amount of Expected Shrinkage
(finished length + loom waste) * percent of shrinkage
Total Minimum Warp Length
Finished Length + Loom Waste + Amount of Expected Shrinkage
For example, if you need trim that is about 60” long, your loom waste will be about 10.5”, you’ve woven and laundered a test band that was 30” off the loom and is 25” after washing, your calculations for the finished band would be like this:
1 - ((25" / 30")*100) = 17% shrinkage
(60" + 10.5") * 1.17 = 82.5" minimum warp length
Step 3: Use a guide string to determine the path closest to your total minimum warp. In general, it’s better if your warp is a little longer than the minimum. Some sample configurations can be found for the Baby Grand Warp Paths - Baby Grand Loom and Grand Warp Paths - Grand Loom.
When plotting your guide string, be sure to exclude the contrasting-colored dowel if you’re doing an inkle woven band. This dowel will hold the heddles and cannot be included in the warp path. When you’ve selected your path, measure the guide string.
Step 4: Add any additional length and multiply the number of ends of each color by the length of your guide string. For inkle woven bands, you will only need to add length here if you intend to add additional fringe by winding a longer warp and tying knots. However, if you are tablet weaving you will need to add 8-10 inches to account for the length of yarn you will use when you are tying the knots to set up your warp.
If you are weaving the included inkle weaving pattern, Inkle Woven Chains, you will have 5 colors to calculate: Lemon Yellow (12 ends), Magenta (8 ends), Amethyst (8 ends), Key Lime (4 ends), and Natural (9 ends) for a total of 41 ends.
If you are weaving the included tablet weaving pattern, Bowties and Diamonds, you will have to add 8-10 inches and then calculate for each of the 3 colors: Lemon Yellow (26 ends), Turquoise Blue (14 ends), and Magenta (8 ends) for a total of 48 ends.
