The main products of Shanghai Jinrui are bolt,Website:http://www.chinajinrui.net, nut, washer, machine screw, self tapping screw and other fasteners with material of carbon steel, alloy steel, stainless steel. Tappying screws have self-tapping screw and self-drilling screw. Self tapping screw has a sharp point which is convenient when screwing the holes. Self-drilling screw has a drill point whicn can drill a hole when used with an electric hand drill. Material usually is low carbon steels with carburization on tapping screw surface. Carburization could increase hardness on the surface. According to the head types, tapping screws usually are grouped into phillips pan head self tapping screw,   phillips countersunk head self tapping screw, slotted head tapping screw, hex head tapping screw,hex flange self-drilling screw, hex washer head drilling screw, etc.