Custom Washer, M12, AISI304

M12 custom washer, 4 mm thick, stainless steel, type of steel – A2.

The Strofix custom washer is an AISI 304 (A2) stainless-steel flat washer for M12 bolts. The washer is 4 mm thick and has a satin finish.

The flat washer is placed between the nut (or bolt head) and the surface being fastened. It distributes the clamping force over a larger area, prevents the nut from digging into softer materials, and provides a smooth bearing surface for consistent tightening. At 4 mm it is considerably thicker than a standard DIN 125 M12 washer (2.5 mm), so it is stiffer and resists bending under load – suited to M12 anchor rod and base plate connections where a thin washer would deform.

This SKU is a single fixed configuration – M12, 4 mm, AISI 304 only.

Use cases:

• Under hex nuts on M12 anchor rods and threaded rods above railing post base plates
• Under M12 bolt heads in base plate and bracket assemblies
• Load distribution on M12 bolted connections in railing, balustrade and canopy systems
• Bearing over slotted or oversized holes, where a thin washer would bend
• Preventing surface damage from nut or bolt head bearing on stainless-steel components

FAQ:

What bolt size does this washer fit?

The washer fits M12 bolts, screws, anchor rods and threaded rods.

How thick is the washer?

The washer is 4 mm thick. This is a custom thickness – a standard DIN 125 washer for M12 is 2.5 mm.

Why choose a 4 mm washer over a standard one?

A thicker washer is stiffer, so it keeps its shape under higher clamping force and spreads the load more evenly. This matters over slotted holes, on softer substrates and in heavily loaded M12 connections.

What steel grade is used?

The washer is AISI 304, designated A2 under the European stainless-steel fastener classification, with a satin finish.

How many washers are needed per bolt?

Typically one washer is placed under the nut. In some assemblies, a second washer may be placed under the bolt head. The specific configuration depends on the installation requirements.

About Anchors & Screws

Anchors and screws are the mechanical fasteners that secure glass adaptors, canopy brackets, railing posts, French balcony holders and other architectural hardware to the building substrate. They transfer structural loads from the visible hardware into concrete, masonry, insulated façades or timber frames.

Strofix supplies 16 products in this category: steel anchors in four lengths (150, 220, 320 and 400 mm) with rod diameters of Ø16 and Ø20 mm, an anchor sleeve (M10 × 80 mm), a spacer tube (L = 100 mm), individual screws (M10 × 45), cup nuts (M10), washers, double stainless-steel threads (M8, 60 and 100 mm), a wood screw (Ø10 × 180 mm), and pre-matched screw-and-fastener sets for 1, 2, 3 or 4 glass canopy brackets – configurable for masonry without insulation, masonry with insulation and timber-frame construction.

Materials are AISI 304 stainless steel and S235 structural steel. The correct fastener depends on wall type, hardware product, bolt size and required embedment depth.