Contents
Nails
How to Work with Nails
Screws
How to Work with Screws
Hollow-Wall Fasteners
Solid-Wall Fasteners
Adhesives
Carpentry Connectors
Nail Guns
Other Fasteners
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Screws
Like nails, screws come in countless varieties. But they all share the same basic design: a threaded shaft topped with a wide head that can be turned with various tools. As the screw is turned, the threads move into the work pieces and pull them together.
In most fastening applications, screws are considered superior to nails. They’re usually much stronger than nails, and easier to remove without harming the work pieces.
Types of Screw Heads
Screws come with differently shaped heads. The most common are flat, round, bugle, oval, hex, and square.
Types of Screw Drive Shapes
In addition to the various types of screw heads, screws also have different drive designs—that is, different-shaped slots on their heads to fit different types of screwdrivers. The majority of screws used commonly in the home have either slotted or Phillips drives:
- Flat-head (slotted): These screws have a single, flat slot across the head that is driven by a flat-blade screwdriver.
- Phillips-head: These screws have a cross- or plus-shaped (+) slot in the head that is driven by a Phillips-head screwdriver.
- Other varieties: You may encounter other screws with specialty drive shapes, such as hex, square (also called Robertson), and TORX® (a six-pointed star shape).
Different types of screwdrivers are shown later in this section—it’s important that you carefully match the type of screwdriver to the head of the screw. If you try to use a flat-blade screwdriver to drive a Phillips-head screw, for
example, you risk stripping the head, which makes it difficult, if not impossible, to drive or remove the screw.
Screw Sizes
Like nails, screws come in a wide range of sizes, with both a length and a gauge (the screw’s diameter, expressed using a number system). Commonly available gauges range from size 2 up to size 16. The actual value of each number doesn’t have much practical use, so just remember that the larger the number, the larger the diameter. Also note that a given gauge may be available in different lengths. The following diagram shows the inch measurements of size 2 to size 16 screws.
Screw Materials
Screws are made from different materials to suit different conditions. Steel, brass, galvanized steel, and stainless steel are the most common for homeowner use.
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Steel: The default material for screws, steel is strong and durable and can be sharpened to a fine point and a sharp thread. It’s good for all applications except those exposed to the elements.
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Brass: Though brass screws aren’t as strong or as durable as steel screws, they look great on furniture hardware. They’re also popular for marine applications because they don’t rust.
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Galvanized steel: Galvanized coatings (made of zinc) are the best way to protect standard steel screws from rust. Hot-dipped galvanizing is considered more durable than zinc plating.
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Stainless steel: Though expensive, stainless steel screws are growing in popularity, especially for deck building. They don’t rust and are much stronger than brass screws.
Types of Screwdrivers
Screwdrivers come in many different shapes and sizes. Here are the basic types, along with their applications and recommendations about what to buy.
Flat-Blade Screwdriver
A flat-blade screwdriver is made for driving slotted screws of all types. An 8"-long model with a 1/4"-wide blade is a good all-purpose choice.
Phillips-Head Screwdriver
A Phillips-head screwdriver fits Phillips screw heads. An 8"-long model with a #2 tip will handle most jobs, but for tiny screws, buy a mini-Phillips driver.
Square-Tip (Robertson) Screwdriver
A square-tip screwdriver is used for square-drive, or Robertson, screw heads. An 8"-long tool with a #2 square tip will work on most screws of this type.
Stubby Screwdriver
Typically about 3 1/2" long, a stubby screwdriver is
designed to work in tight spaces. These screwdrivers are commonly available in both flat-blade and Phillips models.
Multi-Tip Screwdriver
A multi-tip screwdriver has different tips stored in a single handle, which lets you use a wider range of screws without carrying around multiple screwdrivers.
Drill/Driver Bit
A drill/driver bit allows you to use an electric drill or drill/driver to drive screws. These bits are made to fit various screw heads—just chuck the bit in an electric drill or drill/driver and install the screw.
Nut Driver
A nut driver is designed to fit specific hex screw heads and is typically used to drive sheet-metal screws. Nut drivers are often sold in sets of six, from 3/16" up to 1/2".
Right-Angle Screwdriver
A right-angle screwdriver is usually about 4" long and is designed to drive screws in particularly tight spots. This type of screwdriver uses a ratchet mechanism and accepts a variety of short screwdriver bits.
Screw-Holding Screwdriver
A screw-holding screwdriver is designed to fit in places where a screwdriver, but not your fingers, can fit. These screwdrivers come in both flat-blade and Phillips models.
Adjustable Wrench
An adjustable wrench can be used to install many different screws, from small sheet-metal units to large lag screws, as long as the heads have a square or hexagonal shape.
Types of Specialty Screws and Bolts
A wide variety of specialty screws are available for a whole host of applications. Here are some of the most common types that you might need.
Drywall Screws
Drywall screws were originally designed to replace nails for hanging drywall, and they do this job well. With their narrow shafts and bugle heads, they drive quickly through drywall panels and seat just below the surface for easy finishing. But these screws work so well that they’ve become popular for all sorts of household chores, from hanging pictures to silencing squeaky floors.
Self-Tapping Sheet-Metal Screws
Self-tapping sheet-metal screws are used primarily for assembling heating, ventilation, and air conditioning (HVAC) ductwork and joining other light-gauge metal sheets. They’re installed with a power drill outfitted with a drive bit that matches the size and shape of the screw head. Just load the drive with a screw, push it against the duct, and pull the trigger. The screw will drill a hole for the threads that follow.
Lag Screws
Lag screws are heavy-duty screws with coarse threads and square or hexagonal heads. Typically 1/4–1/2" in diameter and 1–6" long, these screws are used to join large wood members in deck building and other heavy construction jobs. Hex-head lag screws are usually driven with a socket wrench; square-head lag screws are turned with an adjustable or open-end wrench.
Machine Screws
Machine screws come in many sizes and shapes for joining everything from the cover plates on your door locks to your car’s engine block. These screws have flat tips and straight shafts with threads along the entire length. Machine screws are
designed to slide through a hole in one of the parts being joined and thread into a hole in the second part: as the screw is tightened, the first part is drawn snug against
the second.
Machine Bolts
Machine bolts are similar to machine screws but used differently. Rather than screw into a threaded hole in one
of the parts being joined, a
machine bolt slides through holes in both parts. The threaded section of the bolt is then fixed with a lock washer and nut. Both machine screws and machine bolts are commonly available in steel, brass, and stainless steel.
Carriage Bolts
Carriage bolts, like machine bolts, are not true screws
because they are installed with washers and nuts. Used primarily for joining large wood pieces, carriage bolts have a dome-shaped head and a square section just below the head. The square section serves as a tamper-proof locking mechanism for the head: as the nut is tightened, the square section is pulled into the wood and keeps the head from turning.
Screw Eyes and Hooks
Screw eyes and hooks are specialty screws that have a threaded shaft joined to a closed eye, a rounded hook, or a right-angle hook. They’re used to hang things from walls and ceilings, from heavy items such as plant baskets to light items such as ornaments or paper lanterns. Usually made of plain steel, screw eyes and hooks are also available in galvanized, stainless, and nickel-plated steel; brass; and even heavy-duty plastic.
Hanger Bolts
Hanger bolts have screw threads on one end and
machine threads on the other. They’re usually between 1 1/2"
and 3" long (with varying diameters) and are used primarily in furniture making to join legs to rails and tabletops. To install a hanger bolt, first drill a pilot hole for the screw end. Then turn two nuts onto the machine threads and tighten them against the shaft. Install the screw end by turning the bolt while holding a wrench on the two nuts.
Concrete Screws
Concrete screws, also known by the brand name Tapcon®, are hardened steel screws designed to attach all sorts of items directly to concrete walls and floors. These screws come in several different diameters with lengths from about
1 1/2" up to 4". To install a concrete screw, first drill a pilot hole in the concrete with a carbide masonry bit. Then drive the screw into the concrete with a drill/driver and a screw-holding socket tool that comes with the screws.
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