Other Fixings & Accessories

Fixings accessories are the supporting components that complete and enhance bolted, anchored, and injection resin fixing installations. CMT Group supplies a comprehensive range of construction fixings accessories including full nuts, washers, channel nuts, wedge nuts, studding, nylon fixings, drill bits, injection resin accessories, MAX silicone sealant, and end caps, covering the complete system requirements of site teams and procurement professionals across the UK.

What Are Fixings Accessories?

Fixings accessories are the components required alongside primary fasteners to complete a fixing installation correctly. In a bolted connection, the nut, washer, and the torque to which the bolt is tightened are all as important as the bolt itself in determining whether the connection meets its design specification. A bolt without the correct matching nut grade, or a bolt used without a washer where a washer is required, is a common installation error that reduces the performance of the connection.

In chemical anchor applications, the accessories are the components that make the installation possible and ensure it meets its rated performance: the correct diameter drill bit to achieve the specified hole size, the mesh sleeve to retain resin in hollow substrates, the mixing nozzle to achieve the correct two-component mix ratio, and the cleaning brush to remove dust from the hole before injection. Without these accessories, a chemical anchor installation cannot meet the load ratings on which the structural specification is based. CMT Group stocks the full range of fixings accessories to support complete system supply alongside the screws, bolts, anchors, and resins in our fixings range.

Fixings Accessories by Type

Our range covers the accessories and system components needed to complete bolted, anchored, and chemical resin fixing installations.

Full Nuts

Standard hexagonal full nuts in metric sizes for use with hex bolts, studding, and threaded connections across construction, structural steelwork, and general site fixing applications. Full nuts must be matched to the bolt diameter and grade. Using a lower-grade nut on a high-tensile bolt reduces the connection to the strength of the nut and defeats the purpose of specifying a higher-grade bolt. Available in zinc-plated and stainless steel to match the corrosion resistance requirements of the application.

Metric sizes · Match to bolt grade · Zinc-plated and stainless · 13 products

Washers

Flat washers and spring washers for use with bolts, screws, and studding connections across construction and structural applications. Flat washers increase the bearing area of the bolt head or nut against the material surface, distributing the clamping load over a larger area to prevent pull-through and surface damage. Spring washers provide a locking function to prevent nuts loosening under vibration and dynamic loading. Available in metric sizes, zinc-plated and stainless steel grades to suit internal and external applications.

Flat and spring washers · Metric sizes · Zinc-plated and stainless · 11 products

Channel Nuts

Channel nuts for use within unistrut and strut channel support systems used in mechanical, electrical, and plumbing installations on construction sites. Channel nuts slide into the channel section and can be positioned anywhere along its length before being tightened, enabling adjustable and field-configurable fixing positions for brackets, conduit supports, cable tray, pipework supports, and HVAC equipment. An essential component for any site using unistrut channel as a support structure. Available in metric thread sizes to suit standard channel sections.

Unistrut and strut channel · MEP installations · Adjustable position · 12 products

Wedge Nuts

Wedge nuts for use in formwork and shuttering systems where a rapid, tool-free locking and releasing mechanism is required. Wedge nuts lock onto tie rods and she-bolts by the action of wedging against the rod thread under load, providing a fast and positive fixing that can be released quickly when striking formwork after the concrete has cured. An important component in the repetitive cycle of formwork assembly and striking on reinforced concrete construction projects. Available in sizes to suit standard she-bolt and tie rod diameters.

Formwork and shuttering · Tie rods and she-bolts · Tool-free locking · 4 products

Studding

Fully threaded steel studding rod in metric diameters for use in chemical anchor systems, adjustable support systems, and bolted connections where a continuous thread length is required. Studding is used alongside chemical anchor resins as the embedded bar, cut to the required embedment depth and projection. Also used in support systems, fixture hanging, and anywhere a continuous length of threaded rod is needed on site. Available in metric diameters and standard lengths in zinc-plated and stainless steel grades. Cut to length on site as required.

Chemical anchor bar · Fully threaded · Metric diameters · Cut to length · 24 products

Nylon Fixings

Nylon wall plugs and frame fixings for screw fixing into concrete, brick, block, and lightweight aggregate substrates. The nylon plug is inserted into a pre-drilled hole and expands around the screw thread as the screw is driven, gripping the walls of the hole to provide the fixing. Available in a full range of sizes to match standard screw diameters and lengths, and in frame fixing combinations that incorporate the screw for single-operation installation. The most widely used masonry fixing system for everyday construction and trade applications. 40 products available.

Wall plugs and frame fixings · Concrete, brick and block · Full size range · 40 products

Drill Bits

Masonry and SDS drill bits in diameters matched to anchor, plug, and fixing specifications for drilling into concrete, brick, block, and stone. The correct drill bit diameter is critical for anchor performance: an undersized hole will not accept the anchor, while an oversized hole reduces the expansion pressure and rated pull-out load of a mechanical anchor. Available in the diameters required to match the standard anchor and plug sizes in the CMT fixings range, including SDS Plus and SDS Max shank formats for rotary hammer drilling. 103 products available.

Masonry and SDS · Matched to anchor diameters · SDS Plus and SDS Max · 103 products

Accessories and Sets

Fixing accessory sets and combination packs providing the components needed for common fixing applications in a single purchase. Accessory sets reduce the need to source individual components separately, saving procurement time and ensuring all necessary parts are available on site together. Available sets cover common fixing configurations used on construction sites, reducing the risk of installation delays caused by missing components.

Combination packs · Reduces procurement time · Complete fixing system · 1 product

Injection Resin Accessories

Accessories for chemical anchor resin installation including mesh sleeves for hollow substrates, mixing nozzles for two-component resin cartridges, and hole cleaning brushes to remove drill dust before injection. Correct hole preparation is mandatory for chemical anchor performance: a hole contaminated with drill dust will not allow the resin to bond effectively to the concrete, significantly reducing the pull-out capacity of the anchor. Mesh sleeves enable chemical anchor installation in hollow block and perforated brick. All accessories must be matched to the cartridge size and anchor diameter being used. 14 products available.

Mesh sleeves, mixing nozzles, cleaning brushes · Hollow substrates · Mandatory for rated performance · 14 products

Silicone

MAX general purpose silicone sealant for sealing around fixings, penetrations, and joints in construction applications. Silicone sealant is used to weatherproof fixing penetrations in external cladding and roofing, seal around frame fixings and window fixings, and provide flexible joint sealing where movement between materials must be accommodated. MAX silicone is compatible with a wide range of substrate materials including glass, metal, PVC, and painted surfaces. Available in standard cartridge format. 4 products available.

MAX brand · General purpose · Weatherproofing and joint sealing · 4 products

End Caps

Plastic end caps for covering and protecting the exposed ends of studding, threaded rod, and protruding bolt threads on construction sites. End caps prevent injury from exposed thread ends in areas where personnel may come into contact with projecting fixings, and protect the thread from damage, contamination, and corrosion during the construction period before the fixing installation is completed or covered. Available in sizes to suit standard metric studding and bolt thread diameters. 2 products available.

Protruding thread protection · Site safety · Metric thread diameters · 2 products

Choosing the Right Fixings Accessories

The accessories required for any fixing application are determined by the primary fixing being used and the installation process it requires. For bolted connections, the nut must match the bolt diameter and grade, and a flat washer is required wherever the bolt head or nut bears against a surface that would otherwise be damaged or allow pull-through. For chemical anchor applications, the full set of accessories (correct drill bit, cleaning brush, mixing nozzle, and where needed mesh sleeve) is mandatory to achieve the rated anchor performance.

For screw fixing into masonry, the nylon plug diameter must match the screw diameter, and the plug length must be at least equal to the screw penetration into the masonry. An undersized plug will not grip the masonry effectively; an oversized plug will not be held tightly by the screw thread. Purchasing fixings accessories alongside the primary fasteners at the point of order, rather than as an afterthought on site, is the most reliable way to ensure all components are available when the fixing installation begins.

Primary fixing	Accessories required	Key consideration
Hex bolt or studding connection	Full nut and flat washer	Match nut grade to bolt grade
Screw fixing into masonry	Nylon plug	Plug diameter and length to match screw specification
Chemical anchor in solid concrete	Drill bit, cleaning brush, mixing nozzle, studding	All four required for rated anchor performance
Chemical anchor in hollow block	Mesh sleeve, nozzle, brush, drill bit, studding	Mesh sleeve retains resin in hollow substrate
Unistrut channel support system	Channel nuts	Thread size to suit channel section specification
Projecting studding or bolt threads on site	End caps	Protects thread and prevents injury from exposed ends

Fixings Accessories Supplied Across the UK

Fixings accessories complete the fixing system and are as important as the primary fastener in achieving the intended performance of a connection. Whether completing a structural bolt assembly, installing a chemical anchor to its rated load capacity, or providing safe protection for exposed thread ends, the correct accessory at the point of installation is what separates a fixing that works as specified from one that falls short in service.

CMT Group has been supplying fixings accessories alongside the full fixings range to UK construction sites for over 20 years. Our accessories range covers the system components needed for bolted, anchored, and chemical resin fixing applications, with over 200 products available across 11 subcategories. We operate our own fleet of 100+ FORS Gold accredited vehicles covering 90% of the UK, with next day delivery standard on orders placed by 5pm by phone or 7pm online, and VIP 2-3 hour delivery on a dedicated vehicle dispatched within 30 minutes for urgent site requirements.

Frequently asked questions

Why is hole cleaning essential before installing a chemical anchor?

Drill dust and debris in the hole acts as a barrier between the resin and the concrete surface. If the resin cannot make direct contact with the concrete wall of the hole, it cannot bond to the base material, and the anchor will not achieve its rated pull-out capacity. ETA-approved chemical anchor systems require the hole to be cleaned with compressed air and a brush in a defined sequence before injection, and this requirement is part of the approval conditions on which the load table values are based. Skipping hole cleaning is one of the most common causes of chemical anchor underperformance on construction sites. The injection resin accessories range includes the correct cleaning brushes for each anchor diameter.

What is the difference between a flat washer and a spring washer?

A flat washer distributes the clamping load of a bolt head or nut over a larger surface area than the bolt head alone, preventing pull-through into softer materials and protecting the surface from damage during tightening. A spring washer, also called a lock washer, is a split ring that is compressed flat when the nut is tightened and applies a continuous spring force that resists the nut loosening under vibration or dynamic loading. The two types serve different functions. In most static structural connections, flat washers are used under the nut and head. In applications subject to vibration, a spring washer is added under the nut in addition to a flat washer. Using a spring washer alone without a flat washer is incorrect practice as it can damage the bearing surface.

What size nylon plug do I need for my screw?

Nylon plugs are sized by the drill hole diameter they are designed to fit and the screw diameter they are designed to accept. As a general guide, a 5mm or 6mm diameter screw requires a 5mm or 6mm plug driven into a 5mm or 6mm hole. An 8mm screw requires an 8mm plug, and a 10mm screw requires a 10mm plug. The plug length must be at least equal to the depth of penetration of the screw into the masonry, not including the material being fixed. For fixing into soft or lightweight materials such as aerated concrete blocks, a larger plug diameter providing more contact area with the substrate will improve the pull-out resistance of the fixing.

What is studding used for on a construction site?

Studding is fully threaded steel rod used in a range of construction applications. In chemical anchor systems, studding is the embedded bar that is inserted into the resin-filled hole and forms the anchor, cut to the required embedment depth and projection length on site. In mechanical and structural applications, studding is used wherever a continuous threaded rod longer than a standard bolt is required, such as in long bolted connections, adjustable support systems, and all-thread fixings. Studding is also used in formwork systems and in unistrut support installations. Being able to cut studding to the exact length required on site makes it significantly more flexible than standard bolts for adjustable and bespoke fixing configurations.

Why are end caps required for projecting threads on construction sites?

Exposed projecting bolt threads, studding ends, and anchor rod projections on a construction site are a laceration and snagging hazard. Under health and safety site management requirements, protruding threads that present a risk to workers must be protected. End caps are the standard and simplest method of protecting exposed thread ends: they push onto the thread end and cover the sharp projecting teeth that cause laceration injuries. They also protect the thread from damage, corrosion, and contamination during the construction period, preserving the thread condition for when nuts and connections are made later in the programme. End caps are a low-cost, high-value safety accessory that should be fitted to all exposed projecting threads as a standard site procedure.

Nylon Plugs vs Frame Fixings: What Is the Difference?

Nylon plugs and frame fixings both use a nylon expansion plug to fix into masonry, but they are designed for different applications and installation methods. A standard nylon plug is inserted into a pre-drilled hole and the screw is driven separately through the item being fixed and then into the plug. This is the standard method for general screw fixing to masonry walls and is appropriate for fixing brackets, conduit clips, shelving, and equipment where the fixing is made from the front of the material being fixed.

A frame fixing is a combined plug and screw assembly where the screw passes through the frame or frame profile and directly into the plug in the masonry in a single operation. Frame fixings are designed for fixing door frames, window frames, and structural timber sole plates to masonry, where the item being fixed has its own clearance hole or slot through which the fixing passes before entering the masonry. The frame fixing plug seats in the masonry and the screw engages the plug through the frame in a single pass. Frame fixings are faster to install for this type of application and ensure the plug is correctly positioned relative to the frame regardless of variations in the frame profile or the depth of the masonry behind it.