Flat Head Screw
Although they’re not as popular as Phillips heads, slotted, square drive or hex drive screws are still used in many applications. To avoid head damage, use the proper driver type for each screw and always pre-drill a pilot hole before driving.
The ubiquitous flat-head screwdriver can be found in every junk drawer. Clever (or impatient) DIYers also put them to work as a chisel, nail-puller or paint-scraper.
Countersunk
A countersunk screw is a screw with an angled head that slopes downward. This allows the head of the screw to rest flush with the surface it’s being installed into, a feature that’s particularly useful when constructing projects where aesthetics are important. When a screw’s head protrudes out from the surface of the material, it can leave marks that aren’t desirable. By burying the head of the screw, this prevents the mark from being seen and also makes the screw much easier to drive into place.
Screws have many different types of heads, and the way a screw’s head is shaped can determine its purpose. Some screws have a flat head, while others have a raised one. Screws that have a raised head are often used for decorative purposes, while those with a flat head are more utilitarian. In addition to head shape, a screw’s drive type can also influence its function. Screws that have a Phillips drive, for example, are designed to fit into a standard Phillips screwdriver. Screws that have a hex drive, on the other hand, are designed to fit into a standard hex wrench.
Another type of screw is the countersunk concrete screw, which was designed specifically for use with masonry materials. The hex drive on these screws allows them to be driven into masonry without needing a drill, and the tamper-resistant drilled spanner drive helps make it difficult to remove the screws by hand. These screws are available in a variety of lengths and diameters, and they can be ordered in either a black or stainless steel finish for various applications.
The screw’s exterior ridges, called threading, allow it to remove excess material as it enters and exits the hole in which it’s installed. In some cases, this excess material rides up along the ridges as the screw is driven into place, creating a raised head that’s known as a hex head. In other cases, the screw’s threading removes enough material that the head sits flush with the surface of the material, which is known as a countersunk head.
Screws that have a countersunk head are ideal for use in construction projects because they create a smooth, even surface after installation. This is especially important in places where the screw will be visible, such as in door frames, where other screw types would leave a bump that might interfere with the frame’s ability to maintain a proper contact with the door. Countersunk screws also help to reduce ongoing stress between the frame and the door, which can lead to cracking and other issues. This is why many construction professionals prefer to use them whenever possible. In the VEX Robotics Competition, these screws are used to build mechanical arms and other small mechanisms in tight spaces, and they’re also often found in other industrial applications. They’re made from high-quality 18-8 stainless steel, which means they’re extremely durable and will last for a long time. They’re also non-magnetic and resistant to corrosion. In order to save time and money, many construction professionals purchase large quantities of these screws.