Irwin 9427 Hanson 5/16"-18 NC Thread 1" Hexagon Machine Screw Die (HCS) - 1" in flats. Ideal for maintenance and repair work. Recommended for use with hex die. Die can be used with a wrench or socket when space is limited. Advanced Die Geometry - Allows faster cutting with longer life. Material Type: High Carbon Steel (HCS) for cutting external threads by hand. Etched: Die size etched on each tool for easy identification.