wholesale bulk screws

Self-drilling fasteners eliminate separate drilling and tapping operations for faster, more economical installations. Check out PSI the most complete selection of self-drilling fasteners and wholesale bulk screws.

Save Time and Money – Eliminate separate drilling and tapping operations for faster, more economical installations.

Starts Exactly Where It Is Placed– State of the art forging process technology and tooling produced to strict specifications provide a sharp, clean and consistent drill point.

Broad Selection of Sizes and Applications– A wide variety of head styles and drive systems are available to meet specialized application and installation demands. Self-drilling screws are available to penetrate thin sheet metal through 1/2″ thick steel.

Selection of Finishes– Screws are provided zinc plated with clear chromate finish. When noted, screws are also available with Stalgard® corrosion-resistant coating which provides 800 hours of salt spray resistance.

Screw threads serve three basic functions in mechanical systems; 1) to provide a clamping force 2) to restrict or control motion, and 3) to transmit power. Geometrically, a screw thread is a helical incline plane. A helix is the curve defined by moving a point with uniform angular and linear velocity around an axis. The distance the point moves linear (parallel to the axis) in one revolution is referred to as pitch or lead. The term internal threads refers to threads cut into the sidewall of an existing hole. External threads refers to threads cut or rolled into the external cylindrical surface of a fastener or stud. The size most commonly associated with screw threads is the nominal diameter. Nominal diameter is a more of a label than a size. For example, a bolt and nut may be described as being ½” diameter. But neither the external threads of the bolt nor the internal threads of the nut are exactly .500 in diameter. In fact, the bolt diameter is a little smaller and the nut diameter a little larger. But it is easier to specify the components by a single size designation since the bolt and nut are mating components.