Dome Nuts M3–M10 — A4 316 Marine Stainless Hex Acorn DIN 1587
Dome Nuts M3–M10 — A4 316 Marine Stainless Hex Acorn DIN 1587
Why choose A4 316 marine grade
These dome nuts are manufactured from A4 (AISI 316) stainless steel to DIN 1587. A4 contains added molybdenum, which gives it markedly better resistance to chlorides and pitting than standard A2 — the difference that matters on boats, coastal properties, swimming pools and anywhere exposed to salt spray or de-icing salt. The polished closed dome conceals the bolt thread, protecting hands and clothing from sharp ends and giving a clean finish.
A4 or A2?
If the fixing lives indoors, or outdoors well away from salt, our A2 stainless dome nuts do the same job for less. Choose A4 316 when the assembly will see salt water, salt-laden air, or persistent damp — the small premium buys years of extra service life.
Sizes available
- M3 / 3mm — light fittings, instruments and small craft assemblies
- M4 / 4mm — deck hardware, brackets and enclosures
- M5 / 5mm — guardrails, fittings and panel work
- M6 / 6mm — handrails, signage and general fabrication
- M8 / 8mm — marine fittings, balustrades and machinery covers
- M10 / 10mm — structural and heavy-duty applications
Pack options
Packs of 2 or 4 for spares and repairs, 10 or 20 for installs and trade work. Each nut is inspected before packing.
How to fit
Thread onto a standard metric bolt or stud and tighten with a hex spanner or socket — the closed top means a torque wrench can be used without marking the cap. Leave 1–2 threads protruding beyond a plain nut and cap with the dome nut, or use a bolt long enough to engage the full depth of the cap. Pair with A4 bolts and washers: mixing grades in a wet environment invites galvanic corrosion.
Delivery
Same-day dispatch on orders placed before 2pm, Monday to Friday. Free UK delivery on orders over £20. Tracked options available at checkout.
