Hexagon head screws — also called hex screws, hex socket screws and hex head cap screws — have a six-sided head and preformed machine threads on the shank, or shaft. You might have seen hex screws abbreviated as HH or HX, depending on the manufacturer or retailer.
Different Types of Hex Head Screws and How They Are Used
Since there are multiple types of hex cap screws varying in material, application and size, you can use them in a variety of commercial, residential and industrial projects.
Hex Head Screw Materials
Hex screws are either fully threaded from one end to the other, offering optimal strength, or partially threaded, ending before the head. These screws are ideal for alignment. Both types are made from various materials depending on the application.
For example, residential or commercial projects might require a more visually appealing finish that fits in with a specific design, while heavy-duty outdoor industrial projects need a screw made from a high-resistance, anti-corrosive material.
Screw materials include:
Hot-dipped galvanized steel
Low and medium carbon steel
Brass, bronze and copper alloy steel
Zinc, chrome or nickel-plated steel
Contact the experts at All Points Fasteners if you’re not sure which type of hex head screw material is right for you.
Hex Screw Sizes and Types
Hex screws are available in the following types:
Self-drilling hex screws:Self-drilling hex screws are commonly referred to as Tek® screws, and they do just what the name suggests. These screws self-drill as you install them, eliminating the need to pre-drill a pilot hole. They are suitable for metal-to-metal applications and have a fluted tip available in various lengths, depending on how thick the metal you’re working with is. It’s a common choice in the HVAC industry, which typically relies on 10×3/4 washer head self-drilling hex heads for installation.
Internal hex screws: Internal hex screws have an internal-facing head indentation and are a common choice for furniture pieces. They require an Allen wrench for installation and removal.
Combi screw: Combination screws, also called combi screws, refer to any screw type that combines more than one head style. Common combi hex screws are slotted hex fasteners or hex and Phillips head combinations for easy use with a standard screwdriver.
Lag screws: Lag screws are heavy-duty fasteners for landscaping, lumber and thick sheet metal applications. They are large with coarse threads and support more weight than standard hex screws. Lag screws with hex heads are often used for wood and sheet metal materials requiring high torque levels.
Sheet Metal Screws: Some hex head screws have built-in washers where the head meets the shank. They have a sharp point on the end for effectively penetrating wood and sheet metal. This design distributes weight evenly over the screw’s entire area for metal-to-metal fastening and some heavy-duty loads.
Painted hex washer head:Painted hex washer head screws are available in various colors and finishes, perfect for siding, roofing, decking and gutter installation where appearance matters to the finished product. Professionally painted screws have a clean finish, free of chips or seams.
Hex bolts also come with an assigned grade, indicated by markings on the head or a manufacturer stamp. The higher the number, the stronger and more hardened that bolt is.
Ways to Use Hex Head Screws
Though you can’t install and remove a hex screw with a screwdriver — unless it’s a special combi screw — the six-point design lets users get more torque when using a hex head screw than they would with a traditional circular head screw. The hexagonal head distributes force across all sides for high-strength fastening and reliable security. If you look closely, you’ll spot hex head screws in most of the buildings, docks and infrastructure projects surrounding you.
Popular hex head screw applications include:
Machinery: Hex head screws are a common choice for fastening and disassembly in machinery projects and equipment assembly.
Construction: Hex screws are used in masonry and construction projects, especially those using steel and wood.
Tight spaces: With six access points, hex head screws are easier to access in tight spaces or spaces with only one side clearance for installation, tightening or removal.
Dirty applications: Hex screws with a solid head instead of an indented or recessed one are perfect for dirty applications, where debris and build-up might threaten the screw’s integrity over time. With no opening to fill, there’s no chance for clogging, and they’re easy to wipe down and shine if appearance or hygiene is important.
How to Screw a Hex Screw
Screwing in hex head screws requires a wrench that fits around the outside of the screw’s head. You need a wrench that matches the size of the screw or an adjustable wrench.
Using a Socket Wrench
Socket wrenches are for hex head screws with an indentation or opening on the top. Before you begin, make sure you have the correct size socket to match the screw you’re trying to install or remove.
Then, follow these steps:
Place the square hold onto the socket’s square knob to attach.
Wait until you hear or feel a click, indicating the wrench and socket are connected.
Choose which direction you want to move on your wrench by turning the dial to the right for tightening or left for loosening.
Place the socket on the screw. Twist the wrench all the way to one side until you feel the screw remove.
If you have a ratcheting socket wrench, instead of removing the wrench, twist it back to the starting point and repeat the same process until the screw is in or out.
Using a Standard Wrench
As with socket wrenches, standard wrenches are available in various sizes and widths and need to match the screw you’re installing or removing. Open-end wrenches surround a hex-head screw on four sides and can slide sideways onto a screw in a hard-to-reach place. Box-end wrenches are closed and must be placed over the top of the screw. Some box-end wrenches have ratchet capabilities.
Here’s how a standard wrench works:
Choose the wrench with a corresponding size to your screw.
Set the wrench around the screw.
Turn clockwise to tighten or counterclockwise to loosen.
If your wrench doesn’t have ratchet action, remove the wrench and reset it on the screw to continue turning.
Repeat the process until the screw is tightened or loosened.
Using an Adjustable Wrench
An adjustable wrench has a moveable jaw so you can make the wrench bigger and smaller as needed to match the size of the screw. You don’t need to find the matching size tool with an adjustable wrench, but it won’t ratchet.
Here’s how to use an adjustable wrench.
Place the wrench loosely around the screw.
Adjust the wrench until it fits tightly around the head.
As with a standard wrench, turn clockwise to tighten or counterclockwise to loosen.
Remove the wrench and reset to continue turning, and repeat until the screw is in or out.
Shop Hex Screws and Other Fasteners at All Points Fasteners, Inc.
All Points Fasteners has the premium fasteners you need, including hex screws from many manufacturers. Fasteners are available in multiple types and sizes that fit your budget and application. Browse the shop today or reach out to a member of our team and tell us about your project — we’d love to help with personalized recommendations.