5/16-9X1 1/4 Phillips Flat Self Tapping Screw Type A Fully Threaded Zinc (Pack Qty 1,250) BC-3120APF

Screws shall be quenched in liquid and then tempered by reheating to 650°F minimum. They are the screw thread covering the whole length of the screw from tip to head and a pronounced thread hard enough for the intended. Steel: Rockwell C45 minimum A thread forming tapping screw with wider spaced threads than a Type-AB and a gimlet point