Sheet metal screws have a fully threaded shank with sharp threads and tip that allow them to cut through metal, wood, plastic, and various other materials. The size of sheet metal screws are commonly shown as a series of three numbers, these numbers represent the diameter, thread count, and length of fastener. A sheet metal screw listed as 4-32 x 1-½” has a diameter size of 4, 32 threads per inch, and a length of 1-½”.
There are two basic types of sheet metal screws, self-tapping screws and self-drilling screws. Self-tapping screws have a sharp tip that is designed to cut through metal, but the metal must be pre-drilled before these screws can be used. Self-drilling screws have a drill point tip that can easily cut through metal without a pre-drilled hole.
The head of sheet metal screws can come in a number of different styles. Pan or round head screw will have heads that extend above the surface of the material after being installed. Flat or oval countersunk screws will be flush with the top of the material after being installed. These screws can come with a Phillips, flat, or combo drive.
Sheet metal screws made out of carbon steel are the most common and typically the most economical. These screws are prone to rust and corrosion when exposed to moisture or chemicals, so they should only be used indoors. Similary if made in Stainless Steel particularly Duplex & Super Duplex Steel grades, they show good resistivity to corrosion and rust. Very Ideal to use for outdoor applications.
Key Features of Sheet Metal Screws are:
• Fully threaded shank
• Very versatile fastener - can be used in metal, wood, and plastics
• Most are self-tapping screws and only require a pre-drilled hole, some come with self-drilling tips
• Specially hardened, sharp threads that allow it to cut into material and form its own internal thread
Zeon typically provides Sheet Metal Screws in Duplex & Super Duplex Steel Grades helping resist rust and corrosion. Sheet metal screws may be Galvanized or Coated with Zinc or Nickel to modify their appearance.