Hex Bolts
A hex bolt — or hexagon bolt — is a type of fastener characterised by its six-sided hexagonal head, which allows for easy gripping and turning using a wrench or Allen key. Typically, hex bolts are partially threaded with a smooth shank portion for strength, and are widely used in machinery and construction. These robust fasteners, also referred to as hexagon screws, are vital for heavy-duty applications like road and building structures. They secure components by being tightened with a nut or directly into tapped holes. Hex bolts are made from materials like corrosion-resistant stainless steel (A2 or A4 grade) and various strengths of zinc-plated steel, designed to resist wear, corrosion, and high mechanical stress.
Types of Allen Key Bolts
While the term hex bolt encompasses all fasteners with a six-sided head, various specific designs exist to suit different functions and load requirements in construction and machinery, including:
Hex Cap Screw
A hex cap screw is a hex bolt variant usually fully threaded along the shaft and manufactured with tighter dimensional tolerances than a standard bolt. It typically includes a washer face under the head to better distribute clamping force and reduce loosening under vibration. Hex cap screws are preferred in high-precision machinery, automative assembly, and applications where a clean, finished appearance is desired.
Hex Socket Head Cap Screw
A hex socket head cap screw is a specialised hex bolt that features a cylindrical head with an internal hexagonal recess. This design requires an Allen key or hex wrench for tightening, making it ideal for applications where the bolt head needs to be flush or where space is limited.
Hex Tap Bolt
A hex tap bolt is a hexagon bolt that is fully threaded from the head to the tip, unlike a standard partially-threaded hex bolt. This full threading makes the tap bolt ideal for tapping directly into a pre-drilled, untapped hole, providing high strength fastening in materials like cast iron.
Hex Flange Bolt
A hex flange bolt is a hexagon bolt that features a built-in washer (a flange) beneath the head. This integrated flange distributes the clamping load over a larger area, making it ideal for joining softer materials or where surface indentation needs to be minimised.
Hex Serrated Flange Bolt
A hex serrated flange bolt is a variation of the hex flange bolt where the integrated flange features small serrations or "teeth" on its bearing surface. These serrations grip the mating material, preventing the bolt from loosening due to vibration and eliminating the need for a separate lock washer.
Hex Machine Screws
A hex machine screw is a smaller diameter hexagon screw that is fully threaded for use with a pre-tapped hole or a nut. They are typically used for fastening thinner materials or components together in assemblies where high-strength, large-diameter bolts are unnecessary.
Hex Lag Screws
A hex lag screw is a large, heavy-duty wood fastener that has a pointed tip and coarse threads, making it function more like a screw than a traditional hex bolt. This design provides superior holding power in timber, making it ideal for joining heavy wood frames or attaching large objects to wood structures.
Hex Head Set Screws
A hex head set screw is a hexagon screw that is fully threaded and lacks a traditional head, instead featuring a recessed drive or flat on top. These screws are designed to be driven completely into a tapped hole to fasten objects together without protruding, commonly used to lock collars or pulleys onto a shaft.
Applications of Hexagon Screws
The strength, versatility, and reliability of the hexagon screw makes it an indispensable fastening solution across numerous sectors, including:
Automotive
The high strength and durability of the hex bolt are essential in the automotive sector for securing engine components, chassis assemblies, and wheel fittings. They withstand constant vibration and high stresses, ensuring the long-term integrity and safety of the vehicle structure.
Construction
In construction, the hexagon bolt is fundamental for its load-bearing capacity in heavy-duty applications like road infrastructure, bridges, and structural steel framing. Its robustness ensures secure, long-lasting connections essential for the safety and stability of major structures.
Appliances
The compact nature of the hexagon screw and its variants, such as the Allen key, makes them ideal for assembling consumer appliances like washing machines and refrigerators. They provide durable, vibration-resistant fastening for internal motors and external panels, ensuring product stability throughout its lifespan.
Electronics
Smaller-gauge hex machine screws are crucial for securing chassis and circuit boards, as well as for mounting sensitive components within electronic enclosures and equipment. Their reliable threading and precise fit ensure that components remain securely in place against minor shocks and thermal expansion.
Furniture
Socket head cap screws, often fastened using a hex key, are widely used in flat-pack and assembled furniture due to their ease of assembly and high clamping force. They provide a strong, stable joint that can be easily tightened or disassembled using a simple Allen key.
Machinery
In industrial and heavy machinery, the hex bolt is critical for assembling large mechanical systems and maintaining the structural integrity of rotating parts and fixed equipment. The high-grade strength and secure clamping of the hexagon bolt ensures reliable operation even under continuous and extreme loads.
How to Choose the Right Hex Bolt
Choosing the correct hex bolt or Allen key bolt for a project depends on several factors that ensure optimal performance and safety:
- Material and Coating: Select stainless steel for corrosion resistance in outdoor or damp environments; zinc-plated for moderate corrosion resistance; alloy steel for high strength.
- Thread Type: A hex bolt with coarse threads is better for quick assembly and wood fastening; fine threads provide higher tensile strength and are preferred in precision applications.
- Length and Diameter: Match the diameter and length of the hex bolt to the thickness and type of materials being joined to ensure proper engagement and strength.
- Strength Grade: Follow industry standards (e.g., ASTM, ISO) and choose a hex bolt with the appropriate tensile strength to suit load requirements.
- Bolt Head Type: For confined spaces use socket head cap screws and flange bolts for applications that require load distribution.
- Environmental Conditions: Consider environmental factors such as temperature, chemical exposure, and mechanical stress of the location where the hex bolt will be installed. Choose heat-treated or coated bolts accordingly.
Your Trusted Partner and Manufacturer for Hex Bolts
Acquiring your hex bolts from RS Singapore’s digital platform is a straightforward and dependable process. Our extensive online catalogue offers a wide selection of top-quality hexagon screw solutions — as well as related products such as torque wrenches and drill bit sets — from leading brands such as ABB and Parker. Once you've selected your preferred products, simply proceed to checkout via any of our convenient online payment options.
When you purchase your hexagon bolts from us, you're investing in quality assurance and expert technical support. This, coupled with our competitive prices, ensures you get the best value without compromising on durability or performance.
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