Cap Screws
Our Cap Screws, also known as Cap Head Screws or Socket Head Cap Screws, are precision-engineered fasteners designed for secure and reliable fastening across industrial, mechanical and engineering applications. A typical cap head screw features a cylindrical head with an internal hexagonal socket, allowing it to be tightened using an Allen key or hex driver. This design provides efficient torque transmission and makes cap screws particularly suitable for machinery, automotive components and assemblies where installation space is restricted.
Our range of cap screws includes A2 and A4 stainless steel, zinc-plated steel and black oxide finishes, with metric thread sizes from M3 to M20. Standard socket cap screws manufactured to DIN 912 are commonly used in mechanical assemblies, while low head cap screws manufactured to DIN 7984 provide a reduced head height for installations with limited clearance.
For alternative drive requirements, our Torx socket cap screws manufactured to ISO 14579 offer improved drive engagement and efficient torque transfer. We also supply Torx low socket cap head screws manufactured to ISO 14580 for compact assemblies and self tapping hex socket cap head screws for applications requiring threads to be formed during installation in suitable materials.
What Are Cap Head Screws Used For?
Cap head screws are commonly used for fastening machine components, securing brackets, assembling mechanical equipment and joining metal parts. A socket head cap screw is particularly useful where a conventional hexagon head bolt may be difficult to access with a spanner. Depending on the application, a cap head bolt can be installed into a pre-tapped hole or used alongside a compatible nut and washer.
High tensile cap screws are suitable for applications requiring increased mechanical strength, while stainless steel cap screws offer corrosion resistance for equipment exposed to moisture and demanding environments. For assemblies subject to vibration, suitable locking nuts or thread-locking compounds can help prevent loosening.
Key Features and Benefits
- Metric thread sizes from M3 to M20 cap screws
- A2 and A4 stainless steel and high tensile steel options
- Standard cylindrical, low-profile and Torx drive designs
- Fully threaded and partially threaded options depending on product type
- Internal socket drives for efficient installation in confined spaces
- Corrosion-resistant materials and protective finishes
- Manufactured to relevant DIN and ISO standards
Common Applications
- Automotive engineering and motorsport assemblies
- Industrial machinery and mechanical equipment
- Precision engineering and metal fabrication
- Construction and manufacturing applications
- Electrical equipment and enclosure assemblies
- Maintenance, repairs and general fastening requirements
How to Choose the Right Cap Screw
When selecting a cap screw, consider the thread diameter, screw length, head dimensions, material grade and drive type. For example, an M12 socket cap screw may be suitable for larger machinery assemblies, while smaller cap head screws are often selected for precision equipment and compact components. Always check the required strength grade, thread engagement and relevant DIN or ISO specification to ensure compatibility with your application.
Need Help Choosing the Right Cap Screws?
Whether you need a socket cap bolt for machinery, cap head screws for engineering assemblies or high tensile socket head cap screws for industrial applications, our team can help you select the correct fastening solution. We can assist with thread sizes, material grades, head styles and specialist requirements.
Can't find the right cap screw size or need a bulk quotation? Call our UK-based team on 01233 713 581 for technical advice, product enquiries or volume pricing. Trade customers can also apply for a Vital Parts Business Account to enquire about trade pricing, credit account options and dedicated account support.
Frequently Asked Questions
A socket head cap screw is a type of fastener that is used to securely join two or more components together. It is distinguished by its specific design, particularly the shape of the screw's head. Socket head caps feature a cylindrical head and there are a few different styles of drive recesses that could be used on the top to fasten it. Today, socket head cap screws are a very popular choice of fastener for a variety of applications across many different industries. They can be manufactured from a wide range of materials, including metals and some plastics. We supply a high grade of stainless steel socket cap screws, these are a premium product that combine excellent strength and durability with fantastic resistance to rusting.
We sell three types of stainless steel socket cap screws. These are the popular hex socket cap screws, low head socket cap screws and torx socket cap screws. While all of these styles of stainless steel socket head cap screws have the same cylindrical shaped screw head, they differ by the shape of the recess used to drive the screw. The standard hex style socket are designed to be driven using commonly available tools such as hex wrenches or Allen keys. The low head socket cap screw features a lower profile head when compared to standard socket cap screws. This can be an advantage when space is limited on the fastened application. Torx socket cap screws feature a star-shaped recess instead of the more common hexagonal recess. This can provide better torque transfer when tightening and can be preferred in some situations.
There are a few different ways to describe stainless steel socket cap screws. They might more generally be referred to as socket cap screws or socket head cap screws. Some other popular terms include cap head screws, hex socket cap screws and hex cap screws. Most people think of the hex head variety when they think of socket cap screws, however we also sell the torx socket cap screws and low head socket cap screws. These are both available in stainless steel.
Din 912 is the DIN standard used to describe the size and shape of the screw. In this case, this translates to socket head cap screws which have a distinctive cylindrical shaped head. Din912 screws are commonly constructed from a range of metals to even some plastics such as nylon. The material that the screw is constructed from will alter its physical properties and the applications which it is suitable for. We sell din912 screws in high quality grades of A2 and A4 stainless steel. This is a premium, high quality material that offers higher strength, better durability and better corrosion resistance than other metals. Din912 screws are commonly used to assemble machinery and equipment in commercial and industrial settings. They are also often used in construction projects to secure structural components and support systems, like steel framing. Fastening engine parts and components inside an automobile is another common use case.
Socket head cap screws generally do not require washers but the specific application and the requirements of the project should be considered. For example, factors such as the load distribution, surface protection and the type of materials being fastened will help to determine whether a washer should be used. The corrosion resistance that stainless steel washers provide can be useful in some applications for protecting the joint from the elements and increasing its lifespan. It's important to consider the specific demands of the application when deciding whether to apply washers to socket head cap screws. If you need technical advice regarding this, the team is happy to help, simply get in touch using our contact us form.
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If you're new to our website you may want to check out our frequently asked questions section for answers to common customer queries.
While browsing the website you may come across abbreviations used for material names that you are unfamiliar with. You can find an explanation for these in our material abbreviations guide.
