Nelsons CNC End Caps are made from aluminium. It is important to know exactly what size material you are capping as each end cap has been designed to fit specific 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.

Our end caps are named according to size: Example 50x50x3 R6

A = 50mm (Outside dimension) 
B = 50mm (Outside dimension) 
C = 3mm (Wall Thickness) 
R = 6mm (Radius Edge)

All our aluminium end caps are 6mm thick. 3mm tightly fits on the inside of the tube and 3mm sits on top.

For more detailed photos of individual products please refer to our end caps in our online shop.

Please check our extensive range of sizes in our online shop before contacting us for a custom sized end cap. We create custom end caps from die drawings or diagrams of your extrusion you are wishing to cap. Visit our Custom Size page for more info

All prices are in Australian dollars and are GST exclusive.

All orders are shipped direct from our factory from the Sunshine Coast, Queensland.  In stock orders received before 1:00pm AEST will be dispatched the same day, if in stock. You will receive a email notification when your order has been dispatched. For more information see our shipping policy.

If you are not satisfied with your product, contact us to organise an exchange or refund within 30 days of purchase. For more info see our shipping policy

Yes - you can powder coat aluminium end caps. Our end caps are supplied in mill finish making them perfect for powder coating, anodising or wood-grain finishing before or after installation. This allows you to match your end caps to surrounding aluminium extrusions, fencing, gates, balustrades or architectural features. For premium finishes, we partner with Kote It, who have extensive experience coating our aluminium end caps, including timber-look finishes for quality results. Contact us here for your custom quote.

No, our end caps are made to fit into the end of aluminium extrusions and can not be fitted into wood.

What are Nelsons CNC end caps made from?
Our end caps are precision CNC-machined from premium 6060 T5 aluminium in mill finish. Which means they are durable, weather-resistant, and perfect for powder coating, or anodising. You can also finish aluminium end caps with timber-look sublimation.

Why choose aluminium end caps over plastic ones?
Aluminium provides a premium, long-lasting finish that won’t crack, fade, or look cheap. They’re weld-free, press-fit for easy install, and can be powder coated to match your project, far superior for fencing, balustrades, and architectural work.

How do I know which size end cap to order?
Measure the external dimensions of your aluminium extrusion (width × height), wall thickness, and note if edges are square or radiused (e.g., R= 6mm). Use a vernier for accuracy. Our end cap sizes follow the format: A×B×C R (e.g., 50×50×3 R6) to perfectly fit the open end of the aluminium extrusion or tube. 

What does the sizing code mean (e.g., 40×40×2 R3)?
A = outer width of the aluminium extrusion (40mm), B = outer height (40mm), C = wall thickness of the extrusion (2mm), R = external radius on corners if present. (3mm) This ensures a tight press-fit with the outside perimeter exactly matching the extrusion or SHS (square hollow section).

How thick are your aluminium end caps?
All end caps are a consistent 6mm thick for strength and a flush, professional appearance. 3mm of the end cap fits tightly inside the hollow section aluminium extrusion and 3mm sits flush on top. 

How do I install Nelsons CNC press-fit end caps?
Simply seat the correct sized end cap on top of the open end of your aluminium extrusion and tap them in with a rubber mallet until the end cap is flush and firmly fitted. No glue, silicone, screws, or welding is needed as our end caps are designed to lock in tightly due to the interference fit. The bevelled underside edge makes insertion easy.

What tools do I need for end cap installation?
Just a rubber mallet (to avoid damaging the aluminium end cap) and ideally a vernier calliper to measure and confirm your exact extrusion measurements before ordering.

Will the end caps stay in permanently?
Yes, when installed correctly into a properly sized extrusion with clean, square-cut ends, they provide a tight interference fit with no movement. Our end caps are designed for static applications. In static (non-vibrating) environments like fencing or handrails, they hold firm. Extreme vibration may affect fit. View our fitment requirements here for more information. 

Do I need to prepare the extrusion before installing aluminium end caps?
No, just ensure the end of the aluminium extrusions are cut square and clean (no burrs or damage). Deburr if needed for smooth insertion and best fit, but usually the end cap will just knock straight into the extrusion nice and tightly.

Can I powder coat or anodise the end caps?
Absolutely, you can powder coat before or after installation. We partner with specialists like Kote It for high-quality finishes, including timber-look/wood grain. All our end caps are supplied as mill finish however we can organise a custom quote for you. Contact us here for more info. 

Are custom sized aluminium end caps available if my extrusion isn’t standard?
Yes! We can manufacture custom press-fit end caps based on your die drawing, DXF file, or accurate measurements. We recommend checking our standard range available on our website first. If you don’t find a suitable option, you can submit your requirements through our Custom Size enquiry form.

Why buy aluminium end caps from Nelsons CNC instead of other manufactures?
Nelsons CNC will match any genuine competitor’s price on comparable aluminium end caps. We also back our products with a 100% satisfaction guarantee - if you’re not completely happy with the fit and quality of our end caps, we’ll provide a full refund. With over 600 sizes in stock, overnight shipping available Australia-wide on in-stock orders, and a fast 2-day turnaround for non-stock sizes, we make ordering easy and reliable.

How do I order aluminium end cap sizes I don’t see in your Nelsons CNC product list on your website? If you can’t find your required size on our website, simply send us the external dimensions of your aluminium extrusion, wall thickness, corner radius (if applicable), and any special requirements. Submit your details through our Custom Size End Cap form or email us at info@nelsonscnc.com.au, and we’ll quote promptly. Once confirmed, we can also add that size to our website for future ordering

Do your end caps fit round tubes?
Yes - we offer round end caps in various diameters. Measure the outer diameter and wall thickness carefully to ensure the aluminium end cap fits the round tube perfectly. 

Can end caps be used on pool fencing or balustrades?
Yes, our round end caps are perfect for pool fencing, blade/batten fencing, balustrades, handrails, and posts as they create a safe, flush finish without sharp edges.

Will end caps fit wooden posts or timber?
No aluminium end caps will not fit wooden posts as they’re designed specifically for the inside of hollow aluminium extrusions/tubes, not solid wood.

Are your end caps suitable for outdoor Australian conditions?
Yes - all our end caps are made from premium quality 6060 T5 aluminium which is corrosion-resistant and built for harsh Australian weather. Powder coating end caps also add extra protection

How many aluminium end caps sizes does Nelsons CNC stock?
We stock over 600 end cap sizes to suit square, rectangle, round, elliptical, oval and glazing sections. We stock the most common fencing, balustrade, and extrusion profiles in Australia.

Do you offer trade and wholesale pricing on Aluminium End Caps?
Yes - register for a trade account view our website to access discounted pricing for fabricators, installers, and businesses.

What are your shipping times?
In-stock orders received before 1:00 pm AEST ship same day from Sunshine Coast, QLD (often overnight express). You’ll get a email once your order has been distpached.

Do prices include GST?
No - all prices are shown GST exclusive (Australian dollars). GST is added at checkout.

What is your returns/refund policy?
60-day returns/exchanges if you’re not satisfied. Contact us to organise - full details in our Shipping & Returns policy.

Can I get free aluminium end cap samples before ordering in bulk?
Yes sample end caps are available so you can check the fit, finish, wall thickness compatibility and that the radius corners match before placing a larger order. Apply for your free samples via the End Cap Samples link on our website. 

Are your aluminium end caps and other products made in Australia?
Yes, all our aluminium end caps and components are 100% Aussie-made,  CNC machined in house on the Sunshine Coast in Queensland Australia. 

Who founded Nelsons CNC and the interference fit aluminium end cap?
Nelsons CNC is founded by Charlie Nelson in 2008, drawing on 20+ years as a CNC machinist in aluminium fabrication he saw a need for an alternative solution to the commonly used black plastic cap. Using CNC machining centres Charlie designed an aluminium end cap that could be easily knocked into any post or extrusion allowing a permanent fit and last the test of time along with the rest of the job. Nelsons CNC now provide a wide range of quality, precision fitting end caps that can be easily powder coated to neatly finish a variety of projects in the aluminium industry including, fencing, balustrades and facades. 

Why used press-fit aluminium end caps instead of welding or screwing caps?
Welding end caps can be a slow, labour-intensive process, each piece needs to be cut, welded individually, then ground back and buffed for a clean finish. Using screws also adds extra installation time, requires drilling and alignment, and leaves visible fixings that can affect the finished look. Our aluminium end caps are designed for faster installation with no welding, drilling, or extra fixings required. They install cleanly without heat distortion, reducing labour time and avoiding additional tools on site. Each cap is manufactured with an interference fit, meaning it is made slightly larger than the internal tube size so it presses firmly into place for a tight, secure hold. Once installed, the cap locks into the tube and is designed not to loosen, rattle, or fall out under normal use. This helps streamline fabrication, reduce finishing time, and save valuable labour on every project

Can Nelsons CNC aluminium end caps be used on blade fencing or louvre systems?
Yes, we have specific elliptical louvre end caps and blade/batten styles designed for tight, secure fits.

Do end caps add weight to fencing/posts?
Aluminium end caps add minimal weight to fence posts as aluminium is lightweight. All our end caps are 6mm thick so they’re strong without adding noticeable bulk.

Are the end caps safe for child/pet areas (e.g., pool fencing)?
Yes, our end caps are flush fit with no sharp edges or protrusions once installed correctly. Our square edge (SE) end caps have a very slight radius (0.05mm) on each corner so they not too sharp.  We also finish all our aluminium end caps in vibrational finishing machines to ensure all end cap edges are smooth. 

Can I install aluminium end caps after powder coating the extrusion?
Yes but ensure the internal bore isn’t heavily coated as this may affect fit.

What is an aluminium end cap?
An aluminium end cap is a protective and decorative fitting that seals and finishes the open end of a hollow tube, post, profile, extrusion, slat, or batten. A Nelsons CNC aluminium end cap is a precision-machined aluminium insert designed to press-fit securely into aluminium sections using a true interference fit, creating a clean finished end without welding, screws, or glue. Each end cap is designed with a 3mm insert that taps tightly into the inside of the hollow section, while 3mm remains visible on the outside for a neat finished edge.

What does interference fit mean when talking about aluminium end caps. An interference fit means the Nelsons CNC aluminium end cap is deliberately machined slightly larger than the internal opening of the hollow tube or extrusion, so when installed it presses tightly into place and grips the inside walls firmly. An interference-fit end cap is a precision-machined aluminium cap designed to fit tightly into the open end of a hollow section aluminium extrusion used in fencing, balustrades, handrails, blade, batten, slat, and architectural systems. This tight press-fit creates a secure hold without welding, screws, or glue, while delivering a clean, finished end.

What does knock-in mean when talking about aluminium end caps?
Knock-in means the end cap is designed to be tapped into place inside the aluminium extrusion using a rubber mallet. Because the end cap it is machined with an interference fit, it grips tightly inside the hollow section and stays firmly in place once installed.

Why use aluminium end caps?
Aluminium end caps create a clean finished end on hollow aluminium sections while protecting the opening from rain, dirt, insects, and debris entering the tube. Nelsons CNC end caps are precision-machined from aluminium and supplied in mill finish, with a true interference fit so they knock in tightly with a rubber mallet and stay securely in place without welding, screws, or glue. They save significant fabrication time compared with cutting, welding, grinding, and finishing a plate, while delivering a precise, professional finish. Because they are aluminium, they are durable in outdoor conditions and can also be powder coated or finished in timber-look coatings to colour match the project.

Is there a minimum order quantity when ordering aluminium end caps?
No, there is no minimum order quantity on our standard stock aluminium end caps, so you can order anything from 1 piece to 1000 pieces. We also offer quantity discounts based on volume. Custom jobs may have MOQs (minimum order quantities) depending on complexity. You can contact us for a free quote here.

How do I contact you for sizing help?
If you need help choosing the correct aluminium end cap size, you can contact us through the Nelsons CNC Contact page, email us at info@nelsonscnc.com.au, or call +61 424 697 003. We’re happy to help match your extrusion by checking your external dimensions, wall thickness, and corner radius to make sure you get the correct interference-fit end cap for your application. If needed, you can also send us a photo or measurements and we’ll guide you to the right size.

Do you have installation videos of your end caps?
Yes, we have installation videos showing how quickly our aluminium end caps fit using the interference-fit design. You can watch our step-by-step video on the How To Install page on our website, or visit our social media channels Instagram and TikTok @nelsonscnc for quick demo videos, product examples, and real installation footage across different aluminium sections. These videos are a great way to see how the end caps tap securely into place with a rubber mallet and sit cleanly flush once installed.

Why is the bevelled edge on the underside of our aluminium end caps important?
The bevelled edge on the underside of our aluminium end caps is an important part of the installation design. It helps guide the end cap smoothly into the opening of the extrusion, making alignment easier and reducing the force needed to start the fit. This is especially important with our interference-fit end cap, where the cap is machined for a tight, secure press-fit. The bevel also helps prevent catching, shaving, or damaging the inside edge of the aluminium during installation, allowing the end cap to tap in cleanly and seat correctly.

Can your aluminium end caps be removed if needed?
Our aluminium end caps are designed with a true interference fit, so once tapped into place they grip firmly inside the extrusion for a secure, permanent fit. If required it maybe be possible the end caps can be removed using pry tools, but some effort is usually needed because they are intentionally machined to lock tightly into position.

Are your end caps suitable for high-end architectural projects?
Yes! Our aluminium end caps are CNC machined for precision, so every cap is manufactured to an exact size for a consistent, accurate fit across every order. We use premium-quality 6060 T5 aluminium, giving the end caps excellent strength, durability, and a clean finish suited to high-end architectural applications. They are supplied colour-ready in mill finish, making them ideal for powder coating or other finishes to achieve a durable, seamless match with the surrounding project. This makes them especially suited to premium fencing, facades, handrails, balustrades, and aluminium screening where clean lines and uniform detail matter. We also have the capacity to supply large project quantities with a fast turnaround to meet commercial project deadlines.