Winding
One gram of wax per kilogram of yarn, and a knitting machine that would otherwise not run.
— h
Running hours before the disc is consumed
Add-on is the input here rather than a prediction: actual transfer depends on disc composition, contact pressure, yarn speed, yarn hairiness and ambient temperature, and it is measured by solvent extraction from the waxed yarn rather than calculated. Wax is applied for knitting and is normally omitted for weaving yarn, where it interferes with sizing adhesion. The friction figures are indicative of the effect being sought and are not derived from the add-on - the relationship between the two is non-linear and saturates, so doubling the wax does not halve the friction again. Disc life assumes continuous running and even transfer across the disc, which wear patterns do not always give.
Yarn Waxing Add-On, Disc Life & Friction Reduction — free, with the formula and a worked example, at Textile School.