In any building or fabrication project—whether you’re constructing a fence, installing handrails, or designing a commercial facade—end caps play a crucial role in both the appearance and longevity of your work.
These small yet essential components are more than just finishing touches — they protect, enhance, and elevate the final look of aluminium extrusions.
At Nelson’s CNC, we specialise in precision-machined aluminium end caps that provide a stronger, longer-lasting alternative to plastic or glued options.
The key feature of our design is that each cap is an interference fit, also known as a press-fit. This means the end cap is machined fractionally larger than the internal dimension of the aluminium extrusion, allowing it to tap in firmly and lock in place without the need for glue, screws, or welding.
This tight-fit design:
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Creates a flush, seamless finish that won’t loosen over time
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Saves installation time — simply tap in with a rubber mallet
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Eliminates welding and adhesive costs
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Ensures a cleaner aesthetic ready for powder coating
Our interference-fit end caps are engineered to precise micron tolerances, so every size fits perfectly across batches — ensuring repeatable results for both trades and fabricators.
What Are Metal Tube End Caps?
Metal tube end caps are fittings designed to close off the open ends of hollow tubes or extrusions. Made from aluminium and available in various shapes they serve several important purposes:
- Protection: Keep out dirt, debris, insects, and moisture
- Safety: Eliminate sharp edges that could cause injury
- Aesthetics: Provide a clean, finished appearance to exposed ends
Common materials used for end caps include plastic, and stainless steel. While plastic caps are popular for their low cost, press fit aluminium end caps offer a higher-end, durable solution—especially for architectural and industrial applications.
Types of Metal Tube End Caps
At Nelsons CNC, we manufacture aluminium end caps to suit a wide variety of applications. Our range includes:
- Square End Caps – Ideal for square posts and rails
- Rectangle End Caps – Designed for wider profiles used in facades, fencing and frames
- Round End Caps – Popular with pool fencing that use round tubing
All square and rectangle metal tube end caps have the option of a square corner or a radius corner.
We specialise in friction-fit caps, which are press-fitted directly into the tube with a few firm taps from a rubber mallet—no welding, glue, or screws required. This not only makes installation faster but also cleaner and more adaptable for powder coating.
Benefits of Using Metal Tube End Caps
Choosing the right end caps provides more than just a polished look. Here are some key benefits:
- ✅ Debris Protection: Keeps dirt, insects, and moisture out of the tube
- ✅ Prevents Rust: Minimises exposure to the elements in outdoor environments
- ✅ Improves Safety: Covers sharp edges that could cause cuts or scrapes
- ✅ Enhances Aesthetics: Creates a clean, professional finish
- ✅ Strengthens Structure: Adds integrity to the ends of hollow extrusions
- ✅ Saves Time: Our friction-fit design speeds up the installation process
Plus, our aluminium caps can be powder coated before or after installation—powdering just the top and sides won’t interfere with the fit thanks to micron-level tolerances.
How to Choose the Right End Cap
To sure which cap you need? Here are a few things to consider:
1. Size & Fit
It is important to know exactly what size material you are capping as each end cap has been designed to fit specific sized aluminium extrusions. Measure the external dimension of your extrusion, wall thickness and note if your extrusion has a square or radius edge. To ensure your aluminium caps are a perfect fit we recommend measuring your extrusion with a vernier or contact your aluminium supplier to locate your material size specifications.
2. Shape
Match the shape of your tube—square, rectangle, or round. Browse our site to find the exact match. As we manufacturer all our metal tube caps in-house, we can create any size end cap - including custom size metal end caps. For more information regarding custom sized metal tube end caps please email our team for a quote.
3. Installation Method
Our friction-fit caps are simple and quick to install and don’t require any tools beyond a rubber mallet. No welding or adhesive is required due to their tight fitment into the end of the extrusion. To install metal end caps follow the instructions below:
- Locate the bevelled edge on the underside of the end cap to seat position onto the aluminium extrusion.
- Place the end cap on top of correct size aluminium extrusion
- Tap end cap several times with a rubber mallet unit firmly fitted
- Fitted end cap will sit tightly with no movement when correctly installed.
At Nelsons CNC, all aluminium end caps are supplied in mill finish, ready for powder coating or timber-look sublimation.
We work in close proximity with Kote It Australia, a trusted local powder-coating and timber sublimation specialist, and many customers either organise coating directly through them or we can coordinate it on their behalf.
End caps can be pre-treated individually and then installed into the aluminium extrusion before the entire fence, balustrade, or façade section is coated as one piece. This achieves a smooth, continuous finish across the full system.
Alternatively, caps can be powder-coated separately and installed afterward — the interference fit remains unaffected, as the powder-coat thickness is measured in microns.
Note: It’s also not necessary to coat the underside of the cap, since that area sits inside the extrusion and is naturally protected once installed.
The result is a durable, colour-matched finish that blends seamlessly with your aluminium work — whether coated in modern architectural tones like Monument, Surfmist, or Woodland Grey, or completed with a timber-look sublimation.
Where to Buy Quality Metal End Caps in Australia
We offer 600 end cap sizes ready to order online, backed by trusetd quality backed by years of customer satisfaction. Since 2008, Nelsons CNC has been crafting high-quality, CNC machined aluminium end caps - founded by veteran machinist Charlie Nelson who recognised the need for a durable, metal alternative to black plastic end caps commonly used in fencing and fabrication.
All metal tube end caps are made from mill finished premium 6060 T5 aluminium to ensure a high quality finish. Our metal tube caps are ideal for any aluminium project that demands strength, precision and weather resistance. All metal caps are made to match your extrusion size, so you get a snug fit that stands up to tough Australian conditions.
Whether you’re a DIY builder, fabricator or a commercial contractor, you’ll find the right solution in our extensive range of square, round, and rectangle metal tube end caps.
👉 Browse our full product range here
End caps may be small detail of the project, but they serve a big role in protecting your work, improving safety, and elevating the final appearance of your project. From fencing and handrails to balustrades and facades, Nelsons CNC offers metal tube end caps that are easy and quick to install and built to last.
Ready to finish your project the right way? Shop our full selection of metal tube end caps or get in touch for custom sizing options today.