Self-drilling screws, also referred to as tek screws or self-tapping screws, have a drill bit point on the bottom of the fastener.  The drill bit point eliminates the need for separate drilling and tapping installations.  The self-drilling screws can be installed into steel materials up to ½” thick.  Self-drilling screws create their own hole and form their own mating thread in the process.  Self-drilling screws are used to fasten together steel or other metals and are typically used to join materials like sheet metal. The TEK number of the tip distinguishes the screws drill bit length.

Thread Cutting Screw

Flooring Screws

Drive Screws

Wood screws are used in construction and woodworking projects.  Flat head wood screws are beveled under the head to fit into countersunk holes to create a flush finish against the wood.  Pilot holes can be drilled with slightly smaller diameters than the screw diameter to prevent splitting of the wood.  Length of the screw is measured under the head for pan head and hex head wood screws.  Flat head and oval head wood screws are measured from the top of the screw for length measurements.