Gin Saw Thickness Impact on Lint Turnout, Lint Value, and Seed Damage

Highlights We compared 0.91 to 1.14 mm thick gin saws by ginning seed cotton from three regions. The gap between the saw and rib was 0.914 mm for the thin saws and 0.800 mm for the thick ones. Response variables were tested using a sequentially reduced (backwards regression) model. Lint “turnout”, lint value, and seed damage did not appear to be significantly different due to saw thickness. Abstract. Over 95% of U.S. cotton post-harvest processing is done using saw gins. Gin saws have long been supplied in three thicknesses. We quantified the effect of saw thickness on lint turnout, lint value, and seed damage, variables that determine producer returns. Saw cylinders stacked with 0.9144 and 1.143 mm (0.036 and 0.045 in.) thick saws, the thinnest and thickest available, were operated in laboratory conditions on three cotton growths (cultivars and production practices) from Mississippi, New Mexico, and Texas in an experiment with five replicates. Fiber quality from samples obtained after lint cleaning was measured using High Volume Instruments (HVI). HVI results were combined with Commodity Credit Corporation Marketing Assistance Loan premium and discount tables to calculate fiber value. Seed damage was estimated after germination using Association of Official Seed Analysts rules. A backwards regression approach in JMP reduced each response variable’s model until only significant controlled and uncontrolled variables remained. Tested variables included: growth and saw thickness and their interaction; processing rate; processing energy; test duration; foreign matter content; moisture content; and ambient humidity and temperature. There was no significant difference in fiber value due to saw thickness. Seed quality differences were insignificant. Differences in lint turnout due to saw thickness also were statistically insignificant. Saw thickness selection may be based on other considerations. Keywords: Cotton gin, Cottonseed, Fiber quality, Gin saw, Saw gin