Northern Fasteners
Mild Steel Box Section 5mm Wall | Heavy Duty Square Hollow Section SHS — Various Sizes & Lengths
Mild Steel Box Section 5mm Wall | Heavy Duty Square Hollow Section SHS — Various Sizes & Lengths
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Heavy-duty mild steel square hollow section (SHS) with 5mm wall thickness — for applications where higher strength, load capacity, and impact resistance are needed. Available in 50x50mm and 100x100mm sizes in 1 metre and 2 metre lengths.
Fully weldable, machinable, and paintable. Ideal for heavy structural frames, machinery bases, barriers, and industrial fabrication where the lighter 2.5mm wall section isn't sufficient.
Specifications
- Wall thickness: 5mm
- Material: mild steel (S275)
- Lengths: 1 metre and 2 metre
- Sizes: 50x50mm, 100x100mm
- Finish: mill scale (uncoated)
Suitable for
- Heavy structural frames and supports
- Machinery bases and industrial platforms
- Security barriers and bollards
- Agricultural and construction equipment fabrication
- Any application requiring maximum rigidity
Frequently asked questions
When should I use 5mm wall instead of 2.5mm?
Use 5mm wall box section where the structure will carry heavy loads, experience impact, or needs maximum rigidity. For lighter frames, furniture, and general fabrication, the 2.5mm wall section is usually sufficient and significantly lighter.
Is it available in other sizes?
We currently stock 50x50mm and 100x100mm in 5mm wall. Contact us if you need other sizes and we'll advise on availability.
Is it weldable?
Yes — mild steel is highly weldable using MIG, TIG, or stick welding.
Does it need coating?
Supplied with mill scale finish. For outdoor or corrosive environments, prime and paint or apply a protective coating.
Delivery
Dispatched within 1 working day. Free delivery on orders over £60. Lengths over 1.5m may require pallet delivery — contact us to confirm before ordering.
Complete your order
Northern Fasteners stocks everything you need for a complete, matched assembly. Always pair your fasteners with the same finish throughout — BZP with BZP, HDG with HDG, A4 stainless with A4 stainless — for consistent corrosion protection and a professional result. Browse our full range of hex nuts, washers, threaded rods, and bolt and nut sets to find everything you need.
BZP, HDG or A4 Stainless — which finish do you need?
Choosing the right finish is just as important as choosing the right size. BZP is ideal for indoor and sheltered use. HDG provides heavy-duty corrosion protection for outdoor, structural, and timber applications. A4 Grade 316 Stainless is the choice for marine, coastal, and chemical environments where no rust is acceptable. Read our guide to help you decide.
Why buy from Northern Fasteners?
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Same-day dispatch
Orders placed before 2pm are dispatched the same working day via tracked courier.
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Free delivery over £60
Free standard UK delivery on all orders over £60. Tracked and reliable.
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DIN & ISO standards
All fasteners are manufactured to DIN and ISO standards. Grade 4.8 and 8.8 as standard.
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Trade & domestic
Competitive pricing for both trade buyers and domestic projects. No minimum order.
Free delivery over £60 — same-day dispatch
Orders placed before 2pm are dispatched the same working day. Spend over £60 and get free standard UK delivery via tracked courier. All our fasteners are manufactured to DIN and ISO standards — properly graded, reliably finished, and competitively priced for trade and domestic buyers alike.
Also need mild steel?
We stock a full range of structural mild steel sections alongside our fasteners — angle iron, box section, flat bar, tube, round bar, and more. Whether you're building a gate, a frame, or a fabrication project, we have the steel and the fasteners to go with it, all in one order.