... screw ,hard disk screws,self tapping screw,nylock/nylon patch screw,waterproof sealing screws,color head screw and precision shaft ... precision screws, such as hard disk screw, self tapping screw, patch screw, water-proof sealing screw, head colored screw, special ... We do all the manufacturing process, such as forming, rolling, heat treatment, surface treatment, thread rod and head painting, checking ...