Whether you are working on furniture manufacturing, shopfitting, cabinetry, or a home DIY project, Insert Nuts provide a strong, reliable threaded connection in wood-based materials.
At Components Direct, we stock a wide range of Insert Nuts designed for secure fixing in wood, MDF and chipboard, helping you create durable, reusable threads where standard screws may fail over time.
Insert nuts are threaded fasteners that are installed into a pre-drilled hole, creating a strong internal thread within softer materials such as wood and composite boards.
Insert nuts are widely used across both professional and DIY environments:
Insert nuts are available in different designs, including screw-in, knock-in, headed and unheaded options. Each offers different features depending on how the fixing is installed and the type of connection required.
Use the comparison table below to understand the differences between Types A, B, D, E, I, J and P and discover which design may be best suited to your application.
|
Insert Nut Type |
Installation |
What makes it different? |
When should I choose it? |
Available |
|
 |
Knock-in |
Coarse external teeth grip the material, with no projecting flange |
For furniture and cabinet fixings where a flush or recessed finish is required. |
M4, M5, M6 |
|
 |
Knock-in |
Similar to Type A but with a circular flange that provides an additional bearing surface. |
For furniture assembly and wooden panels where a headed fixing is required. |
M4, M5, M6, M8 |
|
 |
Screw-in |
Coarse self-tapping external thread with a flange to help control installation depth. |
For furniture, cabinets and removable components requiring a screw-in threaded connection. |
M4, M5, M6, M8, M10 |
|
 |
Screw-in |
Self-tapping external thread without a projecting flange. |
For furniture and woodworking applications where the insert needs to sit flush with or below the surface. |
M4, M5, M6, M8 |
|
 |
Knock-in |
Features a closed end to prevent the fixing bolt from passing through. |
For furniture, tables and other wooden components requiring a closed-end threaded fixing. |
M6 |
|
 |
Knock-in |
Wide, load-spreading base with additional holes for screws. |
For castor applications and suitable furniture applications requiring additional fixing support. |
M8 |
|
 |
Screw-in |
Serrated external threads designed for high pull-out resistance with low installation torque. |
For wood-based materials where an unheaded threaded fixing and low installation torque are desirable. |
M6 |
|
Not sure which insert nut you need? Use our Insert Nut Selection Tool to narrow down the options based on your material and required thread size. Whether you're working with wood, MDF or chipboard, the tool will help you find suitable insert nuts from our range.
Strong & Durable Fixings: Insert Nuts reinforce the material, reducing the risk of stripping or wear, especially in MDF and chipboard.
Reusable Threads: Perfect for applications requiring repeated assembly, such as furniture, enclosures, or panels.
Improved Load Distribution: Spreads load more evenly compared to traditional screws, helping prevent material damage.
Suitable for Multiple Applications: Used across furniture manufacturing, retail displays, automotive interiors, and general woodworking.
We offer a variety of Insert Nut types to suit different materials and installation methods:
The Build: An unheaded, barbed sleeve designed to sit perfectly flush with the wood surface.
Ideal for: Hardwoods and Plywood where a discreet, hidden finish is required.
Uses: Internal cabinet joints, shop fitting, and speaker box construction.
The Build: Similar to Type A but featuring a circular flange (head) to prevent pull-through.
Ideal for: Softwoods and Chipboard where the material might be prone to splitting.
Uses: Office furniture, chairs, and flat-pack repairs.
The Build: A heavy-duty threaded insert with a wide flange and a hex-socket for easy installation with an Allen key.
Ideal for: MDF and Plywood; the "bite" provides incredible resistance to vibration.
Uses: Heavy-duty desks, bed frames, and high-use furniture.
The Build: A self-tapping, flush-fitting insert without a flange. It can be driven deep below the wood surface.
Ideal for: Curved surfaces or thin boards where a flange would get in the way.
Uses: Designer furniture, musical instruments, and intricate woodworking.
The Build: Features a coarse, aggressive external tooth pattern with a closed end to protect the internal thread from debris.
Ideal for: Hardwoods requiring maximum pull-out resistance.
Uses: Children's toys, tables, and outdoor wooden structures.
The Build: Specifically engineered for weight-bearing. Includes a wide base and additional screw holes for ultimate security.
Ideal for: General timber applications requiring extreme structural integrity.
Uses: Castor wheel mounting, heavy sofa legs, and industrial workbenches.
The Build: Features specialized serrated threads that reduce installation torque while increasing grip.
Ideal for: Composite materials and softwoods.
Uses: Creating permanent metal threads in soft-fiber sheet materials.
Once you've chosen the right insert nut, correct installation is essential for achieving a secure and reliable fixing.
Screw-in and knock-in insert nuts require different installation methods, and the correct hole diameter will depend on the insert type, size and material.
Our step-by-step guide explains how to prepare the installation hole, fit both screw-in and knock-in inserts and avoid common installation mistakes.
Learn How to Choose and Install Insert Nuts
Streamline your assembly by pairing our threaded inserts with high-quality Furniture Bolts and Jointing Fasteners. For specialised applications like seating or trolleys, our Industrial Castors provide the perfect weight-bearing partner for our Type J range. Ensure you have a standard Hex Key (Allen Key) on hand for our screw-in types to achieve the necessary torque without stripping the drive.
Use Insert Nuts when you want a clean, hidden finish or need to screw into the face of the wood. Use T-Nuts when you can access the back of the board for a permanent 'clamped' fix.
BFA is dedicated to raising awareness of the key qualities that make British-made furniture stand out to consumers, retailers, contract specifiers, architects, and international audiences.
Membership is open to manufacturing companies across all sectors, with associate membership available for suppliers, retailers, and supporting businesses within the trade.
The membership of the BFA includes some of the oldest and most highly regarded furniture manufacturers in the UK. Members are from every part of the UK and from every area of manufacture including upholstery, cabinet and bed and mattresses.
British Manufacturers Association members are provided with advice and services on a range of topics including employment law, health and safety regulations, flammability law and timber regulations.
For MDF and chipboard, choose an insert with enough external grip and, where pull-through is a concern, a flange or head to spread the load. Type B, Type D and Type P can be suitable depending on whether you need a knock-in or screw-in installation.
Because MDF and chipboard vary in density and can be prone to crushing or blowout, always check the product data sheet and test a sample in the intended board thickness.
The correct pilot-hole size depends on the insert’s external body diameter, its design and the material you are fixing into. As a general rule, softwoods and MDF usually need a hole slightly smaller than the insert’s external diameter so the insert can grip, while hardwoods may need a hole closer to the external diameter to reduce the risk of splitting.
Important: Always use the recommended pilot-hole size shown on the individual product page. If you are unsure, request a sample and test it in an offcut of the same material and thickness.
No. Most insert nuts can be installed using standard tools:
For repeat installation or higher volumes, an appropriate installation tool or jig can improve speed and consistency.
Choose zinc alloy for most indoor furniture, cabinetry, retail displays and general woodworking applications. It is a cost-effective option with good corrosion resistance in dry, internal environments.
Choose stainless steel for outdoor use, damp or humid environments, bathrooms, marine applications, or anywhere rust resistance is a priority.
Yes, but end grain provides less consistent grip than face grain or edge grain. Screw-in inserts, such as Type D or Type E, are generally the better choice because their coarse external threads create a stronger mechanical connection in the fibres.
For load-bearing end-grain applications, test a sample first and consider a flanged insert or an alternative fixing method where the load is high.
Stop before the insert is fully seated. For a screw-in insert, carefully remove it and start again.
To keep it straight, thread the insert onto a suitable bolt and use the bolt as a guide or handle while installing it. Installing slowly and keeping the tool square to the surface will help you achieve a 90-degree fit.
The metal internal thread can be reused repeatedly, which is one of the main benefits of an insert nut. However, if you remove the whole insert from the board, the external hole may become slightly enlarged or damaged.
If you need to reinstall an insert in the same hole, use a suitable wood glue or epoxy to improve retention. For critical applications, drill a fresh hole in a new position where possible.
Yes. We recommend testing insert nuts in your actual material and application before committing to a production order. Request a sample and our team can help you identify suitable options based on your board material, thickness, thread size and load requirements.
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