Unite metric fasteners
Metric Fasteners for Bolted Connections and General Assembly
Choose the right metric fasteners for the job
Our metric fasteners range brings together the standard hardware many professional buyers need for everyday bolted joints, brackets, supports and general assembly work. Instead of treating bolts, nuts and washers as generic commodities, we make it easier to compare the formats that actually affect installation speed, clamp-up and the finished result.
On this page you can explore hexagon head bolts and screws, flange-head bolts, carriage bolts, washers and matching nuts. It is a practical starting point when you need a complete metric fastening combination rather than a single part in isolation.
What is included in our metric fastener range
Hexagon head bolts and screws
Choose our hexagon head bolts and screws when you need a standard metric fastener for brackets, supports and everyday bolted assemblies. This is the core choice for general workshop, site and maintenance work, with both partly threaded and fully threaded formats depending on how the joint should clamp.
Hexagon flange-head bolts
Use our hexagon flange-head bolts when you want a broader integrated bearing surface and a more efficient assembly without always adding a separate washer. They are a practical option when speed, repeatability and clean clamp-up matter in routine metric fastening work.
See sizes and details for our hexagon flange-head bolts on page 88 in the catalogue.
Carriage bolts
Choose our carriage bolts when you want a smooth visible head and a square neck that helps stop rotation during tightening. They are especially useful in applications where appearance matters or where a conventional hexagon head is not the best fit for the assembled detail.
See sizes and table data for our carriage bolts on page 89 in the catalogue.
Washers
Use the right washers when you need to spread load, support the joint and match the bolt and nut combination properly. Our range covers flat round washers, larger-diameter washers and square washers so you can adapt the assembly to the detail you are fastening.
See dimensions and washer types on page 90 in the catalogue.
Hexagon nuts
Choose our hexagon nuts for straightforward metric assemblies where you want a standard, familiar fastening method that works across a wide range of bolts and site conditions. They are the natural starting point for many general-purpose bolted joints.
See dimensions and standards for our hexagon nuts on page 91 in the catalogue.
Flange nuts and lock nuts
Use our flange nuts when you want a broader bearing area, and choose self-locking nuts when resistance to loosening is more important in service. This part of the range helps you finish the joint with the retention method that suits the application better.
See details for our flange nuts and self-locking nuts on page 92 in the catalogue.
Detailed metric fastener data in our catalogue
Use the catalogue below to compare bolt formats, washer types and nut options in one place. It is the fastest way to move from a general metric fastener requirement to the right hardware combination for the job.
For this page, the most relevant pages are the metric hardware section itself. Threaded rods and accessories sit in the next catalogue section and belong more naturally on their own dedicated page.
Need help choosing the right metric fasteners?
Choosing the right metric fasteners is not only about thread size. The right combination of bolt format, washer type, nut style and material suitability affects assembly speed, joint quality and long-term performance.
We help contractors, fabricators, installers and technical buyers choose practical fastening combinations for real projects. If you want support, we can help you narrow down the right option and point you to the most suitable hardware in our range.
How do I choose between a hexagon head bolt and a hexagon head screw?
Choose between them based on how the joint should clamp and how much thread you want running through the assembly. A partly threaded bolt is often the better fit when you want a cleaner shank through the clamped materials, while a fully threaded screw can be the more practical choice when you need thread engagement through more of the joint thickness.
When is a flange-head bolt the better choice?
A flange-head bolt is often the better choice when you want a broader bearing surface built into the fastener itself and a simpler assembly sequence. It can be a practical option in repetitive work where you want a more efficient installation and a stable clamp-up without relying on a separate washer in every case.
When should I use a carriage bolt instead of a standard hexagon bolt?
Use a carriage bolt when a smooth visible head is preferred and when the square neck helps keep the fastener from rotating during tightening. It is a useful option in details where appearance matters, where access is limited on one side, or where a conventional hexagon head is less suitable for the finished assembly.
Why does washer type matter in a metric fastening?
The washer type affects how the load is distributed and how the joint bears against the connected material. A standard flat washer, a larger-diameter washer or a square washer do not solve the same job in the same way, so choosing the right washer helps the full metric fastening combination perform as intended.
What is the difference between a standard hexagon nut and a self-locking nut?
A standard hexagon nut is the default choice for many normal bolted joints, while a self-locking nut is used when resistance to loosening is more important. If the application involves movement, service vibration or a stronger need to keep the nut in position over time, a locking nut is often the safer choice.
Can Unite help us choose the right metric fastener combination?
Yes. We can help you match bolt, washer and nut combinations to the practical needs of the job instead of leaving you to piece the assembly together yourself. That is often the quickest way to avoid mismatched hardware and move faster from requirement to order.