Toothed gin saws have been used to separate cotton fiber from the seed for more than 200 years. A scientific analysis of saw-tooth design has never been published and the optimum saw-tooth design has not been found. Initial laboratory ginning evaluations of some modern gin saw teeth have shown differences among designs in ginning rate, fiber length measurements, and textile processing quality. The saw gin stand used for testing was a Continental Double Eagle that had been cut down to 46 saws. Four different sets of 16-in diameter, commercially available replacement saws were obtained from independent suppliers. These four sets, along with the standard Continental saw set, were used for five test saw treatments. The test saws varied in the number of teeth per saw from 328 to 352. Testing of the five saw treatments was replicated four times for a total of 20 ginning lots. Each ginning lot was analyzed for raw fiber quality and textile spinning performance. Most of the raw fiber properties were not significantly affected by the saw treatments. However, HVI length and length uniformity after one stage of lint cleaning and seed cotton processing rate were significantly different among saw treatments. The ginning rates varied by 34% from the lowest to the highest at 75% gin stand motor load. The ginned fiber was processed into both open-end and ring-spun yarns. There were few significant differences among saw treatments for the open-end yarn, but there were significant differences for the ring-spun yarn in ends down (a measure of spinning efficiency), yarn evenness, and yarn strength. This indicates that gin saw-tooth design might significantly affect spinning efficiency and yarn quality. Research is currently being done to further understand how gin saw-tooth design affects ginned fiber quality and textile processing quality factors.
