High speed Yarn tensile testing machines have been made to increase production of yarn tensile data. No comparisons with tensile data from older, slow-speed testing machines have been successful in determining whether these machines produced the same results as the newer, high-speed testing machines. This work compares yarn tensile tenacity data from three different machines. A family of five ring-spun yarn sizes, each with five different twist factors, were made that practically covers the entire spinning range of the staple fibers. A method of analyzing yarn data that determines the number of broken fibers and the effective fiber length acting in each yarn was used to convert the yarn tenacity into yarn tenacity per broken fiber per effective fiber length. The converted yarn data from each machine shows the effects of the time-to-break on test results and also how the single strand yarn tensile test results differ from one machine to another and from the yarn-skein tensile test results.