Flat Head Screws are one of the most common fasteners and can be found in many products. There are several different head types available depending on the application.
Some of the most popular include: Socket Cap Screw heads which often are installed flush with the surrounding materials to provide a smooth appearance and easy access to the drive. Trim head options offer a narrower head. Truss heads, sometimes called mushroom heads, offer a larger bearing surface and lower profile than pan or round heads.
Countersunk
Unlike other screw types, Countersunk screws feature a head that sits level or beneath the surface it’s screwed into. This enables workers to cover the head of the screw with cap or filler materials after installation, which isn’t possible with other types of threaded fasteners.
The flat surface created by burying the head of a Countersunk Flat Head Screw makes it perfect for use with door frames, where other screw types would protrude and create unnecessary stress between the frame and the door. These fasteners can also be used in machinery and with sheet material that’s too thin to work with other types of screws.
There are several different types of head styles available for Countersunk Flat Head Screws. The most common is the standard ‘flat’ head, which has a flat top and a drive recess on its side. Another option is the ‘trim’ head, which has a narrower head that’s more suitable for certain applications. The ‘oval trim’ head has a decorative rounded finish and is often used for switch covers.
Hex
Screws come in a variety of head styles and shapes. Each type of screw has its own purpose and uses, from fastening wood to installing sheet metal. One common fastener type with a flat head is the socket cap screw. These screws have an internal hex (Allen) drive and can be used in many types of projects.
Hex flat head socket cap screws have a shoulder sloped at an 82-degree angle for imperial or around 90 degrees for metric screws to allow them to sit flush with the surface they’re installed into. They are ideal for applications where the appearance of the screw is important or the clamping material is too thin to countersink the screw.
Hex heads are angled under the head for a flush finish in countersunk holes, and they can be installed and removed with a hex wrench. These screws are also available in a variety of finishes to match any project’s aesthetic requirements, including painted heads for wood and drywall.
Torx
Most screws come in a few different head and drive types. These include (not necessarily comprehensive) flat head, Phillips head, allen head and torx head. Each type has advantages and disadvantages depending on the project in which they are used.
For example, torx screws have a six-point star shape that reduces cam out and allows the screwdriver to better grip and transmit more torque to the fastener. This makes them ideal for woodworking projects.
In addition to reducing cam out, Torx screws offer superior strength. They are also more resistant to corrosion and rust than other screw heads. When security is a concern, consider tamper-proof torx screws (also known as pin hex or spanner). They have an extra pin in the center of the six-point star socket that prevents normal torx drivers from engaging with the fastener. You will need a special tamper-proof bit to remove these screws.
Multi-Tooth
Several types of flat head screws feature multiple teeth on the drive tip. The more teeth, the greater the torque capacity of the screw. They’re used in high-load applications like automotive, mechanical and electrical engineering.
A good screw point bites into non-pilot-drilled surfaces quickly and creates an entry hole for the screw’s shank and threads. It also resists outward pressure that can cause splits and bulges in wood or other materials.
Some screws have heads coated in color to match the material they’re going into. For example, GRK screws with a white or sand finish work well in treated lumber. Other colors are available, too. The SPAX and Weather Maxx screws have special coatings that help extend their lifespan and can be used in ACQ, CA or CCA-treated wood as well as redwood, cedar or other hardwoods.