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How to cut aluminium box section with a metal blade

Updated: October 2026

The bar is on the bench, 800 mm or 1,000 mm of mill-finish aluminium, and you need a shorter piece. How to cut aluminium box section, for these walls, is a clamped metal cut, a square line, and a filed edge. The walls are 1.3 mm, 2 mm, or 3 mm on the title of the 60 × 40 mm listing. This is workshop practice from the [aluminium rectangular tube comparison](/hub/rods-and-pipes/aluminium-rectangular-tube) on 16 October 2026, not a cutting trial. A qualifying purchase through our links can earn a commission at no extra cost to you. Welding is where this page stops.

The bar is on the bench, 800 mm or 1,000 mm of mill-finish aluminium, and you need a shorter piece. How to cut aluminium box section, for these walls, is a clamped metal cut, a square line, and a filed edge.

Our top picks

Fabal Aluminium Fabal 30 × 15 × 1.3 mm, 800 mm

Best overall

Fabal Aluminium Fabal 30 × 15 × 1.3 mm, 800 mm
6.6/10about £12.53
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Fabal Aluminium Fabal 30 × 15 × 1.3 mm, 1 m

Rank 2

Fabal Aluminium Fabal 30 × 15 × 1.3 mm, 1 m
7.8/10about £13.15
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Aluminium Online Aluminium Online 30 × 20 × 2 mm

Best value

Aluminium Online Aluminium Online 30 × 20 × 2 mm
5.2/10about £11.00
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On this page
  1. 1.Set up the cut
  2. 2.Hacksaw or a non-ferrous blade
  3. 3.Take the burr off
  4. 4.A simple joint, and where to stop

Set up the cut

Mark the finished length on the wide face and wrap the line onto the other three faces. Clamp the tube so the offcut cannot drop and pinch the blade. On a 1.3 mm wall that pinch closes the bore and leaves a hooked burr. Fabal allows about ±2 mm on the supplied length, so an 800 mm bar may already be 798 mm before you start. If you are cutting the 60 × 40 × 3 mm title, confirm you are holding a tube and not the sheet stored in the technical block. If the bar is the wrong size, use the aluminium rectangular tube sizes page before you waste the length.

Hacksaw or a non-ferrous blade

A hacksaw with a metal blade will cut every wall in this set if the strokes stay steady. Forcing a fine blade through a 3 mm wall heats the cut and wanders off the line. A mitre box, or a square guide clamped to the bar, keeps a 90-degree end. A mitre saw is cleaner if the blade is sold for aluminium. One UK listing, the Evolution 230 mm × 25.4 mm × 80-tooth blade, states a 2.4 mm kerf and a maximum of 3,000 rpm for extrusion and box section. Those figures belong to that blade. A wood blade is the wrong disc. The large teeth grab a hollow wall, the offcut kicks, and the cut snatches. Wear eye protection. The swarf is small and sharp.
Fabal Aluminium Fabal 30 × 15 × 1.3 mm, 800 mm

Testsieger

Fabal Aluminium Fabal 30 × 15 × 1.3 mm, 800 mm
6.6/10about £12.53
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Take the burr off

The lip on a 2 mm or 3 mm wall will cut a hand, and it will stop a sleeve that should have started. A single-cut file, drawn along the outside edge and then around the bore, takes that lip off. A light chamfer is enough. You are not thinning the wall. Workshop notes, including a Practical Machinist thread with a Norfolk contributor, treat a single-cut file as the ordinary tool for an aluminium edge. Wipe the swarf out before you fit anything inside. On the 1.3 mm Fabal wall the burr is thin and easy to fold flat, so file it rather than bend it. The bore is smaller than the title, and the corner radius makes a calculated hole optimistic.

A simple joint, and where to stop

Two 1 m bars joined end to end will not become a stiff 2 m beam. The joint is the weak point, and none of these listings states a working load. A through-bolt or a rivet in the 1.3 mm wall is more honest than a self-tapping screw. Drill a clearance hole and use a washer. Do not hang a person, a roof, or a floor from the joint. The Health and Safety Executive treats welding fume as a hazard to control. This page will not give a welding method. Capping a wet garden frame is on the aluminium box section for outdoor frames page. If you have not chosen the bar, the conditional pick is on the best aluminium rectangular tube page.

Common questions

Can I cut this with a hacksaw?
Yes. A metal-cutting hacksaw blade will cut the 1.3 mm, 2 mm, and 3 mm walls if the bar is clamped and the offcut is supported. Mark the line on all four faces. The 3 mm title takes longer and heats up if you rush it. A wood blade on the same saw is not a substitute.
Which blade if I use a mitre saw?
Use a blade sold for aluminium, not the timber blade already on the saw. The Evolution 230 mm blade cited above is an 80-tooth non-ferrous blade with a stated 2.4 mm kerf and a maximum of 3,000 rpm. Those numbers are that product’s specification. Read the plate on the blade you fit, and keep the offcut clear of the teeth.
How do I get a square end?
Wrap the mark around the tube and use a mitre box or a clamped square so the hacksaw cannot lean. Check the end with a try square before you drill. An out-of-square end on a 1 m bar shows up as a gap in a frame, and filing one corner to hide it shortens that face.
Will a wood blade do?
No. Coarse wood teeth grab a hollow wall. The offcut can kick, and the cut snatches off the line. Fit a metal hacksaw blade or a non-ferrous mitre blade before you switch anything on. Leaving the wood blade in place is how a thin wall gets torn rather than cut.
How do I join two 1 m bars without welding?
Bolt or rivet them, with a clearance hole and a washer on the thin wall, and treat the joint as the weak point. A self-tapping screw in 1.3 mm aluminium is a poor thread. These listings give no working load, so the joint is for a light frame, not a span that carries a person. If the finished length must be one bar, buy the longer length instead of joining two amazon cuts.
When should I stop and not weld it at home?
Stop when the next idea is a weld and you do not already weld aluminium with fume extraction. HSE treats welding fume as a hazard to control. A hacksaw cut does not create that fume. Painting, bolting, and riveting stay on this side of the line. A weld for a stair, a floor, or a roof is a professional job.

Related pages

Aluminium box section vs steel

Aluminium rectangular tube

Best aluminium rectangular tube for a short light frame

Aluminium rectangular tube sizes, wall and cut length

Aluminium box section for outdoor frames in the UK

Sources

Public UK sources and amazon.co.uk listings from the category digest, checked on 16 October 2026. Shelf prices and star lines can change after that date.

  1. Consumer Rights Act 2015 (retrieved 16 October 2026)
  2. Consumer Rights Act 2015, section 9 (satisfactory quality) (retrieved 16 October 2026)
  3. HSE: welding (retrieved 16 October 2026)
  4. HSE: COSHH basics (retrieved 16 October 2026)
  5. Approved Document A: structure (retrieved 16 October 2026)
  6. Using the UKCA marking (retrieved 16 October 2026)
  7. BS EN 755-2: mechanical properties of extruded aluminium (retrieved 16 October 2026)