Sheet Metal Screws, also referred to as Self-Tapping Screws, are a hardened screw with a fully threaded shank, sharp spaced threads and a sharp pointed (gimlet) tip that allows them to cut into thin gage metal, wood, plastics, fiberglass and other suitable materials.
Sheet metal screws can pierce, thread into and fasten many softer materials without pre-drilling, but for use in materials such as sheet metal and hard woods a correctly sized pilot hole should be pre-drilled before these screws can be used successfully. When used in thin gage metals with a pre-drilled pilot hole a self-tapping screw is capable of cutting it’s own threads into the hole for securely fastening two metal items together, fastening wood to metal or metal to another suitable substrate material.
Our zinc plated steel Sheet Metal Screws feature a sharp Type A or AB style point with a more closely spaced thread form that allows their use over a wide range of materials and material thicknesses. They are available in head styles such as Hex, Pan, Truss, Countersunk Flat or Oval Heads. They feature a clear zinc chromate plating to provide protection against normal atmospheric corrosion, but they will rust when exposed to the elements, moisture or chemicals.
The length of a Hex Head sheet metal screw is measured from underneath the head. A rule of thumb for determining correct pilot hole size for a screw is to drill a hole in the size range of it’s minor diameters, (see Tech Specs below). We have included a suggested Pilot Hole size for metal in our Technical Specifications section on this page. When necessary, a test installation may be required to confirm the correct pilot hole size for fastening into different thicknesses and types of materials. Hex Washer Head Sheet Metal Screws are also available in 18-8 Stainless Steel.