A Twist Optimum for Handspun Warp Yarn: Where Added Twist Stops Buying Strength and Starts Buying Breaks

Every spinner knows that twist makes yarn stronger, up to a point, and that beyond that point the yarn becomes hard, lively, and prone to snarl. What is rarely stated is where the point lies for yarn destined for the warp, where strength is not the only currency: a warp yarn also has to survive the loom, and a yarn that is marginally stronger in the test frame but breaks twice as often at the heddles is a worse warp yarn by any honest accounting. This paper puts both effects into one calculation and finds the twist multiplier that maximises usable value, defined as tenacity less a charge for expected loom breaks. In the computed results, the best multiplier is 3.5; the best tenacity is 18.34; the best breaks is 16.2; the best value index is 12.68; the strongest multiplier is 4.5. Twist warp yarn to the usable-value peak, not the strength peak. The study is simulated, not measured; all inputs are stated assumptions, printed in the accompanying computation, which readers may replace with their own values and re-run.