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Square Nuts
Square nuts are four-sided internally threaded fasteners designed to provide secure, reliable connections in demanding applications across the UK's construction, automotive, manufacturing and engineering sectors. At Vital Parts, we stock a comprehensive range of square nuts manufactured to exacting DIN standards, available in A2 and A4 stainless steel grades. Our square nut range includes chamfered square nuts (DIN 557) and square weld nuts (DIN 928), ensuring you have the right fastening solution for every application.
Square nuts offer several distinct advantages over traditional hexagonal nuts. Their four-sided profile provides a larger bearing surface area, distributing load more effectively across the fastened material and significantly reducing the risk of surface damage or deformation. The square geometry makes these nuts particularly resistant to loosening under vibration and dynamic loads, as they can be positioned against flat surfaces or within channels to prevent rotation during installation. This anti-rotation feature eliminates the need to hold the nut whilst tightening the bolt, making installation considerably easier in tight spaces or blind locations where access is restricted. Square nuts are less prone to rounding than hex nuts, offering improved grip with standard spanners and reducing the likelihood of tool slippage during assembly.
Our stainless steel square nuts deliver exceptional corrosion resistance and mechanical strength, making them ideal for both indoor and outdoor applications. A2 stainless steel (also known as 18-8 or 304 grade) provides excellent general-purpose corrosion resistance suitable for most UK environments, whilst A4 stainless steel (316 grade) offers superior resistance to chlorides and marine atmospheres, making it the preferred choice for coastal installations, chemical processing facilities, and food production environments. All our square nuts are manufactured to meet stringent quality standards, ensuring dimensional accuracy, consistent thread quality and reliable performance across medium to heavy load applications.
Key Features and Benefits:
- Larger bearing surface area compared to hex nuts distributes clamping loads more evenly, protecting softer materials from damage
- Four-sided profile resists rotation when positioned against flat surfaces or within channels, eliminating the need for dual-tool installation
- Superior vibration resistance in dynamic applications reduces the risk of loosening over time
- Less prone to rounding during installation and removal, extending tool life and improving productivity
- Chamfered variants feature rounded top faces that improve aesthetics and eliminate sharp edges for safer handling
- Weld nut variants provide permanent threaded inserts with precision pilots for accurate positioning and thread protection
- High-grade stainless steel construction ensures long-lasting durability and excellent corrosion resistance
- Manufactured to recognised DIN standards guaranteeing dimensional consistency and compatibility with standard threaded components
- Easy installation in confined spaces and blind locations where traditional hex nuts would require difficult access
Common UK Use Cases:
- Structural steel construction and framework assembly, where square nuts provide secure load-bearing connections in beams, trusses and support structures
- Automotive and agricultural machinery manufacturing, securing chassis components, engine mounts, body panels and implements where vibration resistance is critical
- Furniture production and joinery applications, including the assembly of commercial furniture, shopfitting, exhibition stands and restoration of vintage pieces
- Railway track construction and maintenance, where square nuts have been traditionally used for securing rail fixings and require high clamping forces
- Channel and strut-based installation systems in mechanical and electrical services, where square nuts slot into mounting channels for rapid, secure fixing without rotation
- Metal fabrication workshops using square weld nuts to create permanent threaded inserts in sheet metal assemblies, enclosures and brackets
- Marine and coastal infrastructure projects requiring A4 stainless steel square nuts for superior resistance to saltwater corrosion
Equivalent Standards:
- DIN 562 (Germany, Deutsches Institut für Normung) - thin square nuts specification
- DIN 557 (Germany) - chamfered square nuts specification
- DIN 928 (Germany) - square weld nuts with projections specification
- DIN EN 562 (European standard harmonised with DIN 562)
- PN 82151 (Poland, Polski Komitet Normalizacyjny)
- UNI 5596 (Italy, Ente Italiano di Normazione)
Related Vital Parts Products:
- Standard Hex Nuts - full hex nuts (DIN 934), half hex nuts and studding connector nuts for general fastening applications
- Locking Hex Nuts - nyloc nuts with nylon inserts providing vibration-resistant self-locking properties
- Flange Nuts - serrated and non-serrated flanged nuts offering larger bearing surfaces and improved load distribution
- Stainless Steel Flat Washers - essential for use with square nuts to protect surfaces and distribute loads evenly
Call Vital Parts:
For quick quotes, same-day dispatch, custom sizes, or bulk discounts, call our sales line on 01233 713 581. Businesses can register for a Vital Parts Business Account to benefit from priority shipping, trade pricing, free product samples, credit accounts and a dedicated account manager.
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Frequently Asked Questions
What are square nuts?
Square nuts are a fastening solution that is named after the distinctive square shaped head of the nut. They are a four sided nut, which sets them apart from the commonly used six sided hex nut. Square head nuts have largely been superseded by hex nuts, but there may still be some specific applications where they offer advantages. For example, they are commonly used alongside square headed bolts and screws.
What is the difference between hex nuts and square nuts?
The biggest difference between hex nuts and square nuts is the obvious difference in shape. Hex nuts have six edges and square nuts have four, this means that you will need different tools to grip them and tighten them. Pliers or an adjustable wrench may be your best bet for tightening square headed nuts, for hex nuts you will likely be best off with a socket wrench. The different shape of square nuts makes them better for certain specific applications than hex nuts. While hex nuts are more common in use, square nuts do provide anti-rotation and slide-in installation benefits.
What are the advantages of using square nuts over hex nuts?
One of the biggest advantages of using square nuts is that they provide some anti-rotation benefits when compared to hex nuts. The square shape of the nut helps to prevent rotation that may occur during installation. When using a hex nut, there is a possibility of the nut rotating while tightening. Another advantage offered is the ability to slide-insert square nuts into channels or tracks before securing them with a bolt. This slide-in feature can make assembly faster and easier in projects that require frequent adjustments or component changes. Similarly, square nuts are commonly used for channel based assemblies where they will perfectly fit into the channel's slots. This increases the ease of adjustment and application of components along the length of the channel. Sometimes the uncommon aesthetics of the square head nut may also be used to provide a more unique finish than hex nuts.
What are square nuts used for?
Square nuts are often used in applications that utilise channels or tracks. The shape of the nut allows it to easily fit through the channel and also allows for easier adjustment. The resistance to rotation that square nuts provide is also useful for this tightening along the length of the channel. There are specific use cases in furniture assembly and woodworking where hex nuts might not be as easily accessible as a square nut. Similarly, square nuts have specific uses in the automotive industry where they are found as fasteners on certain vehicle parts and components.
What are square nuts also known as?
The most commonly used term to describe this component is square nuts. We call them stainless steel square nuts to place an emphasis on the high quality grade of material that we use for the product. Customers might also know refer to them as square threaded nuts or square head nuts. A technically minded user may use the DIN standard number to specify the part, and for our range of square nuts this would be din562.
What thread sizes of square nuts do you sell?
We're pleased to offer a wide range of metric thread sizes for square nuts, from M2 up to M10. Our top selling square nuts are the m6 square nut and the m8 square nut. UK customers also commonly purchase m3 square nuts and m4 square nuts and use them for a variety of different projects and applications. If you need a metric thread size that isn't listed, or you require some non-metric sizes, please let us know on our contact us page. As we can still supply parts that aren't part of our standard catalogue!
How fast can I get my order?
Need your parts tomorrow? Our rapid same day dispatch has got you covered! Simply place your order before 4pm Mon-Thurs or 2pm Friday and select our Next Day Delivery service in the shopping cart. We also offer Guaranteed AM delivery when required, in addition to a Saturday delivery option.
If you don't mind waiting, we have a Free delivery method for orders over £30, and an economic £4.85 2nd Class delivery for orders between £20-£30.
Can I get a Free Sample?
Free Samples can be requested through our product pages, displayed in the sizing table beside the product you require. Please note you can always give us a call on 01233 713 581 or contact us on Live Chat to discuss samples.
Do I need to Sign Up for an account?
You do not need to sign up to place an order, but it is recommended if you'd like to gain loyalty points, giving discount off future orders. To learn more about loyalty points, please view our rewards scheme page.
I am not sure what parts I need?
If you're unsure which part you need then please do not hesitate to give one of our friendly Sales Team a call on 01233 713 581 and they can assist you. Alternatively, we're active on Live Chat during office hours. You can open this using the button in the bottom right corner of the website. Alternatively, you can write to us using our contact form.
Do you offer Returns on Products?
We offer a return period on all of our products to give you peace of mind, to view our policies and learn more about this process should it be required, please see our returns policy page.
Can you supply different colours of this product?
In most cases we have the facilities to offer you different colours of a product, specific to your requirements. Minimum order quantities may apply depending on the manufacturing technique in question, but please get in touch with any queries you may have.
Is there a minimum order value?
Please note that there is a minimum order value of £10 through our website (inclusive of VAT).
If you're new to our website you may want to check out our frequently asked questions section for answers to common customer queries.
What do these abbrievations mean?
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.