Self Tapping Screws (Sheet Metal Screws)
While similar to a machine screw in many respects, a self-tapping machine screw, differs in that the lower portion of the shank is designed to carve threads as the screw is driven into an untapped hole. This feature gives the self-tapping screw the advantage over a self-drilling screw as new threads are not cut should the screw be re-installed. Self-tapping screws are available in many different drive styles, head styles, and types, each offering its own benefits. Some of the types AFT offers are Type AB, Type A, Type B, and Type F self-tapping screws. Read more below to see our full range of self-tapping screws.
Types of Self-Tapping Screws
Floorboard Thread Cutting Screws have a countersunk Torx drive (or 6-lobe), machine screw thread pitch, blunt point, tapered entering threads, and multiple cutting edges. Larger diameters may be supplied as a thread rolling screw rather than thread cutting. Floorboard screws are available in longer sizes then standard Type-F screws, and specifically designed for installing wood floors into truck trailers.
Particle Board Screws are the same as a coarse thread drywall screw but available in shorter lengths than standard drywall screws. They feature a bugle head, spaced threads, extra sharp point, and black phosphate finish. Particle board screws are designed specifically for use in dense woods, such as chipboard and particle board.
Security Self Tapping Screws are sheet metal screws (self-tapping screws) that require a special tool for installation or removal. For additional information view our security screws.
Self Piercing Screws are commonly used with thin metal, such as a metal roof, and does not require pre-drilled or pre-punched holes. The undercut area beneath the head allows for greater length of thread engagement. The self piercing screw is designed with twin leads; a single lead thread rolled to the tip of its extra sharp point, and a second thread spaced 180 degrees apart. They are commonly supplied with Neo-EPDM sealing washers to protect against leakage and reduces the chance of the screw coming loose from vibrations.
Self Tapping Screws (Thread Forming Screws)
- Type AB thread forming tapping screws have spaced threads and a gimlet point. They are used for self-starting in thin metal or resin-filled plywood. Type AB is recommended over Type A, especially in brittle materials.
- Type A thread forming screws have wider spaced threads than Type AB and a gimlet point.
- Type B thread forming screws have spaced threads and a blunt point with incomplete entering threads. Type B is used for molded or through holes in thin metal, non-ferrous castings, plastics, or resin-filled plywood.
Thread Cutting Screws
- Type 1 thread cutting screws have a machine screw thread pitch, blunt point, tapered entering threads, and a single cutting edge. Steel thread cutting screws are commonly used with steel sheets, structural shapes, special alloy steels, cast iron, brass, or plastic. Stainless steel screws offer greater corrosion protection but have a more limited application range due to it being a softer metal. Unlike Type 23 and Type 25, Type 1 thread cutting screws are not designed with a chip cavity.
- Type 23 thread cutting screws have a machine screw thread pitch, a blunt point, tapered entering threads, a single wide cutting edge, and a chip cavity. Steel Type-23’s are most commonly used for cast iron and zinc, aluminum die castings, and plastics. It provides excellent chip clearing with minimum tightening torques. 18-8 stainless steel thread cutting screws offer additional corrosion resistance.
- Type 25 thread cutting screws have spaced threads, a blunt point, tapered entering threads, a single wide cutting edge, and a chip cavity. Steel thread cutting screws are typically used for plastics and other soft materials with molded or through holes, and is excellent for clearing chips. Stainless steel thread cutting screws offer greater corrosion resistance but have a more limited application range because it’s a softer metal.
- Type F thread cutting screws have a machine screw thread pitch, blunt point, tapered entering threads, and multiple cutting edges. Steel thread cutters are commonly used in heavy gauge sheet metal, aluminum, zinc and lead die castings, cast iron, brass, and plastic. Stainless steel screws offer additional corrosion resistance.
Thread Rolling Screws have a triobular thread.
U Drive Screws have spaced spiral threads and a blunt point. They are forced under pressure into the material and are considered permanent where other tapping screws can be removed.
As a supplier of self-tapping Screws, AFT Fasteners offers a wide variety to fit every application. Shop our selection online or contact us if you need assistance finding the proper size, style or quantity. Our experiences sales team is available to help.