Flat Washers Form A M3–M12 — A4 Marine 316 DIN 125

Why choose these A4 316 marine Form A flat washers

Form A flat washers are the standard general-purpose washer for metric bolted joints — a bearing face wider than the bolt head spreads load and protects the surface beneath. Pressed from A4 (316) marine grade stainless steel to DIN 125, the added molybdenum resists salt water and chloride attack far better than A2, which makes these the right choice for boats, coastal installations and anywhere exposed to de-icing salt. For interior and general outdoor work, our A2 304 stainless washers cost less and are perfectly adequate.

Sizes available

Seven metric bores to DIN 125: M3, M4, M5, M6, M8, M10 and M12. Use the dropdown to choose the size and pack you need.

Typical uses

Boat fit-outs and deck hardware, pontoons and jetties, coastal signage and railings, trailer and slipway fittings, swimming pool and spa equipment, outdoor kitchens, and any joint exposed to salt spray or chloride where A2 would eventually stain.

How to fit

Place the washer under the nut or the bolt head with the flat face against the workpiece. Pair A4 washers with A4 bolts and nuts — mixing grades in a wet environment invites galvanic corrosion at the joint. Form A is the standard medium-thickness washer; step up to a large-OD DIN 9021 penny washer where more load spread is needed.

Delivery

Same-day dispatch on orders placed before 2pm — free UK delivery on orders over £20.