Screws are fasteners that hold an object in place and allow you to quickly join two parts of any object by either twisting them or joining them together. Screws, unlike nails, can be easily removed and reused. The majority are made of steel, brass, or aluminum, although specialized screws made of plastic or nylon are also available.
Screws are made of four major components: the head, shank, thread, and tip. The head is usually slotted to accommodate the right screwdriver type. The leg joins the head with the thread, while the tip is the screw’s end driven into the material using force. Once the tip enters, the thread holds on to the object and pulls the screw farther into the hole.
The thread of a screw determines how much torque it can produce. The more torque that can be made, the closer the threads are together, and this also implies that additional twists will be required to tighten the screw.
It is a simple yet highly successful invention that has resulted in the development and creation of many types of screws available today in various sizes.
Things to Consider When Buying the Right Kind of Screws
1. Material and Coating
The material and finish of the screws are essential in determining what type of work the screw can withstand, where it should be used, and how durable it is. Some materials allow screws to withstand greater weight, while others help in preventing rust and corrosion. If the material is prone to corrosion due to moisture, several coatings can give protection to it.
Steel is the most used material for screws, but the problem is that it erodes when it comes in touch with moisture. Steel screws require a corrosion-resistant coating or plating to keep water out. Zinc plating, hot-dipped galvanized, and black phosphate are some common coatings and finishes.
The other coatings that make steel screws corrosion-resistant are powder-coated paint, electro-coated, polymer, ceramic and specific proprietary changes. The decorative finishes like brass and nickel plating provide corrosion resistance but are best used inside. Bright steel screws provide no corrosion resistance as they are meant for internal usage where they won’t contact moisture.
2. Drive Type
Screws are of two drives; slotted and Phillips or plus type. The combination of these drives works with every kind of screwdrivers that are widely used; however, screw heads with these drive types easily come out.
On the other hand, square drive and star drive screw heads reduce cam-out resistance. They have a good grip on the driver and often allow for single-handed driving in various situations. The Hex head screws require a wrench or socket and ratchet, and some screws work with nailers.
These screws are compiled in sticks or coils for easy driving, but you can also remove them with the help of a drill or a screwdriver.
3. Thread Type
Screws with coarse thread have larger thread spacing. They are often meant for softer materials like wood or drywall; sheet metal screws also feature coarse threads. Coarse-threaded screws are easy to install and remove. On the other hand, fine threaded screws are designed for use in pre-tapped holes in metal or with nuts.
Smaller gaps between the threads provide a tighter grip, but they are more challenging to install and remove. A higher thread count expressed in threads per inch (TPI) denotes more delicate threads on a typical screw.
A more delicate threaded metric screw has a lower threaded pitch or space between lines in millimeters. Twin threads, dual threading, and jagged threads, for example, offer minor splitting, enhanced fastening, and easier driving.
4. Head Type
Some screw heads are made to accommodate countersink holes, which are very deep holes in a workpiece. Based on the screw, the head may be flushed with the surface, as with flat head and bugle-head screws, or the piece of the head can be visible above the surface, as with oval head screws. Some screws are self-countersinking – means as you drive them, they cut the countersink hole.
Screws having non-countersink heads, like round heads or pan heads, lie on the top of the surface. Screws with truss heads, washer heads, and wafer heads have a broader contact area underneath the screw head than other types of screws. Trim-head screws have smaller heads that are also easier to conceal than other types of heads.
5. Screw Size and Length
The screw’s diameter is generally the outer diameter of the threads. Diameters of 1/4 inch and less or 5/16 inch and less are shown with a # and a whole number. For example, a screw with a primary diameter of 3/16 inches is a #10 screw. Lower numbers correspond to smaller diameters. Once you install the screw, the length specifies the distance between the tip and the workpiece surface.
On flathead countersinking screws, this runs from the tip to the top of the screw. The length of an oval head countersinking screw is measured from the point where the screw head touches the workplace’s surface.
It goes from the tip to the bottom of the head of non-countersinking screws. A countersinking wood screw with a 5/32-inch diameter and a 1.5-inch length is labeled as a: #8 x 1.5-inch countersinking head wood screw.
Types of Screws
1. Slotted and Plus Screws
Screws come mainly in two types; slotted and Phillips or plus type. A screw head enables the screwdriver to apply tension while fastening it and sliding minimally. You can use a screw head with either a slotted or a plus screwdriver; however, the screw heads tend to fall out easily if they don’t have enough torque and threads. They are further subcategorized based on usage:
2. Wood Screws
These are sharply pointed screws used for non-structural, wood-to-wood fastening. Wood screws have coarse threads and an unthreaded shank close to the head, allowing the screw to grip the wood pieces closely.
3. Structural Wood Screws
Structural wood screws are similar to wood screws that have a coarse thread and an unthreaded shaft. They are, nevertheless, significantly more robust than stand wood screws. Depending on the building regulations, you can use them as lag screws or bolt screws.
4. Brass Screws
Small brass screws with numbers 0 or 1 are used for attaching decorative hinges. They are also known as flathead wood screws. Moreover, ensure that you have the correct sized screwdriver for these screws. You can remove the heads with a larger screwdriver.
5. Cement Board Screws
These screws are fully threaded and are used to fasten backer boards onto the wall studs or subfloor during tile jobs. They provide a covering that protects them against corrosion caused by moisture and mortar. Cement board screws are available in wood, metal, or both.
6. Drywall Screws
Drywall screws are fully threaded and used for indoor projects, for example, attaching drywall to studs. Fine-threaded screws are used to hand drywall on wood studs, whereas coarse threaded screws are used on metal studs. Drywall screws are not strong enough to hold cement board and tile.
7. Deck Screws
Deck screws are made for use in a deck, fencing, and other outdoor construction projects. Like standard wood screws, the wood deck screws have a coarse-threaded section and an unthreaded shank. The composite deck screws feature finer and small heads. Some even have a second set of threads for preventing the composite material from heaping at the screw head.
8. Lag Screws
Lag screws are used to secure heavy items or components that carry severe loads. Since lag screws have hex heads, you must install them using a wrench or socket and a ratchet. Eye lag screws are simple wood screws with a ring at the crown for attaching rope or chain may also be seen. They cannot support the load that a lag screw or bolt can.
9. Sheet Metal Screws
The sheet metal screws, like the others, are the fully threaded screws used to join sheet metal and softer materials. You can use some of them with pre-drilled holes, while others include self-drilling points.
10. Concrete Screws
Concrete screws are designed for use in fixing concrete or another masonry. Some of these screws are self-tapping and allow you to drive them directly into the material without the need for pre-drilling, while others function with masonry anchors.
11. Multi-Material Screws
The multi-material screws contain design qualities that allow them to be used in various work components, including wood, sheet metal, drywall, masonry, and plastic.
Picking the right kind of screws for your needs is essential as several types are available on the market made for different purposes. You can choose the screw that you want according to your needs. Although it might sound simple, it’s not actually. You have to consider many things, such as those mentioned above, to get the right kind of screws you want according to the task at hand.