Black Serrated Flange Nuts M3–M10 — A2 Stainless DIN 6923

Why choose these Black Serrated Flange Nuts

Our Black Serrated Flange Nuts combine the corrosion resistance of A2 (18/8) stainless steel with a chemical black oxide finish that gives a clean, low-glare appearance — ideal for marine fit-outs, automotive trim and architectural metalwork where a discreet look matters. Manufactured to DIN 6923, the integral flange replaces the need for a separate washer and the serrations on the underside bite into the joint surface, providing excellent resistance to vibration loosening.

Sizes available

• M3 — electronics enclosures and small assemblies
• M4 — brackets, panel work and light fittings
• M5 — furniture, signage and trim
• M6 — handrails, gates and general fabrication
• M8 — automotive, marine deck fittings and machinery
• M10 — structural fixings and heavy-duty installations

Pack options

Available in packs of 10 units for repairs and small projects, or packs of 20 for larger installs and trade use. Each nut is inspected before packing.

Typical uses

• Vibration-prone joints — engines, exhaust systems, trailers and motorbike trim
• Marine deck and rail fittings where a black finish is preferred
• Black ironmongery, gate hardware and architectural metalwork
• Furniture, signage and any installation where a separate washer would be awkward

How to fit

Place the nut onto a standard metric bolt or stud with the serrated face against the work surface and tighten with a hex spanner or socket. The serrations are designed to embed into the joint — for soft or finished surfaces, place a plain washer underneath to protect the finish. Tighten to the bolt manufacturer’s recommended torque.

Delivery

Same-day dispatch on orders placed before 2pm, Monday to Friday. Free UK delivery on orders over £20. Tracked options available at checkout.