GMNA C144 PDF

This standard for Metric Oval 90° Countersunk Trim Head 6-Lobed Socket Machine Screws conforms in all essentials, except head proportions and driving provisions, with the American National Standard covering metric machine screws. Basically, the smaller proportions of the trim heads were derived by applying to the respective screw diameters the 1976 standard oval head diameters applicable to the next smaller screw size, and specifying a rounded edge.