Self-Drilling Tek Screws

Self-drilling screws, or Tek screws, see frequent use in commercial heating and air conditioning installations. These fasteners feature drill-style tips, allowing users to skip the pre-drilling process and safely secure materials, particularly sheet metal. Tek screws are valuable in numerous applications, with metal roofing projects being one of the most common.

We have an extensive selection of nails, screws, and other fasteners for all kinds of construction jobs. We offer self-drilling Tek^® screws in carbon steel and also two types of stainless steel, 410 and 18-8, with the option to have painted heads to complement various surfaces, and different shank sizes are available to complete any metal-on-metal project you are working on. Let us help you get the job done efficiently with our time-saving tools.

Different Sizes of Tek Screws

Each project needs specific fasteners to accomplish a given goal. On a screw, the shank is the long, threaded part that connects the tip and the head. You generally need the shank to be a particular size to suit the metal you’re working with. Think of these threaded rods like clothes — the bigger the shank, the larger the size. As such, a number 10 screw will be larger than a number 8.

The type of head style you need can also vary based on the job. The most popular head style features six flat sides and is known as a hex head screw. These fasteners are commonly used in the HVAC industry, especially the 10×3/4 hex washer head.  Measuring across the head of these self-drilling screws will help you determine the shank number. The three most common head sizes and their corresponding shanks are:

• 1/4 hex drive: Size 6 or 8 shanks.
• 5/16 hex drive: Shank sizes 10 and 12.
• 3/8 hex drive: Size 14 screw shank.

The most common screw used by heating and air companies is the 5/16, as a size 10 shank works well for attaching sheets of metal. 

Understanding Which Type of Screws You Need

If you’re a contractor, it’s necessary to be as specific as possible when asking for any type of fastener. Tek^® screws are indeed self-tapping screws — screws that cut their own threads — but it isn’t because of their tip. The tip is self-drilling while the threads are self-tapping.  When asking for a tek screw, many people ask for a self-tapper which could end up getting you the wrong screw since sheet metal screws and zip screws as also self-tapping.  Just make sure you describe the tip of the point, and you should be good.  We like to describe it as a drill bit type tip or one that resembles a shovel.   There is one main difference between these types of screws:

• Self-tapping screws: The threads allow the screw to tap its own threads into the material.
• Non-self-tapping screws: Machine screws are one type of this type of screw.  They require a pre-threaded nut or other female insert.

Knowing the difference between various types of fasteners saves you time and lets you get back to the job site with the necessary tools in hand.