Unslotted Ind Hex Washer 1/4" Across The Flats Full Thread Self Piercing Sc Zinc Needle Pt

AISI 1018 - 1022 or equivalent steel: May be used in thin metal (less than .050 thick). Eliminates need for pre-drilled or pre-punched holes. Undercut area beneath the head allows greater length of thread engagement. Twin lead threads help to reduce driving torque. Screws shall be quenched in liquid and then tempered by reheating to 650°F minimum