40×40 Aluminium Extrusion Profile – Cut to Length

The 40×40 aluminium extrusion is one of the most common square profiles used for CNC machine frames, workbenches and light industrial fixtures. It suits machine builders, workshop owners and advanced hobbyists who need a stable, easy to work with material for a chassis that has to stay square under load.

This 40×40 aluminium extrusion is sold by the millimetre, so you order the exact length your build needs instead of buying a fixed bar and cutting off the leftover. That keeps waste low and makes it simple to plan a frame down to the last joint.

Features of the 40×40 Aluminium Extrusion

The profile has a square 40x40mm cross-section with internal T-slot channels running along all four faces. These channels accept standard T-nuts and cap screws, so brackets, corner connectors and mounting plates bolt straight on without welding or drilling into the material itself.

Being aluminium, the extrusion resists rust and surface oxidation even in workshops with coolant mist or humidity, and it is light enough for one person to handle a two or three metre length. It also cuts cleanly on a chop saw or bandsaw with a standard metal-cutting blade.

• Square 40x40mm cross-section
• T-slot channels on all four sides
• Sold per millimetre, cut to your exact length
• Corrosion and oxidation resistant
• Low weight compared with steel box section
• Compatible with standard T-nuts and corner brackets

Where the 40×40 Aluminium Extrusion Profile Is Used

Machine builders reach for this 40×40 aluminium extrusion when framing up CNC routers, laser gantries and 3D printer enclosures, where a rigid but lightweight frame keeps moving mass down without sacrificing stiffness. It also turns up in workbenches, tool stands, guarding panels and conveyor frames around a small workshop.

Because the T-slot channels run the full length of the bar, it is just as useful for modular fixtures that get reconfigured often, such as jigs, enclosures or test rigs. If you are sourcing brackets, T-nuts or other frame hardware to go with it, the full CNC parts catalogue covers the rest of what a build like this needs.

What to Check Before Buying

Confirm the slot width and T-nut size before ordering brackets or fasteners, since profiles from different manufacturers are not always interchangeable even when the outer dimensions match. Mixing incompatible T-nuts into a 40×40 aluminium extrusion channel is the most common fitting mistake, and it usually only shows up once the parts are on the bench.

Measure twice before submitting a length, since the profile is cut to order and cannot be extended once it has left the workshop. If your frame design uses mitred corners or angled cuts, add the extra length needed for the cut angle rather than ordering the finished face-to-face dimension.

Installation and Maintenance

Assembly is done with corner brackets, T-nuts and cap screws dropped into the slots, so no welding equipment or drilling jig is required; a hex key and a square are usually enough to true up a frame. For background on how these profiles are manufactured, see the overview of the aluminium extrusion process on Wikipedia.

Once built, a 40×40 aluminium extrusion frame needs very little upkeep: wipe off swarf and coolant residue so it does not sit in the slots, and check that fasteners have not worked loose after the first weeks of vibration from a running machine. Re-tightening periodically keeps the frame from developing play at the joints.

FAQ

Can the 40×40 aluminium extrusion be cut to a custom length? Yes, it is sold per millimetre, so you specify the exact length required for your build.

What size T-nuts fit the slots? Standard T-nuts sized for a 40 series slot fit directly; check the slot width against your bracket supplier’s specification before ordering.

Is it strong enough for a CNC router frame? Yes, the square profile and internal ribbing give enough rigidity for router and laser gantries when braced with corner brackets at the joints.