Zinc Plated Flat Washers - DIN 125 Form A / ISO 7089 (M3 to M36)

Our zinc plated flat washers are manufactured to the dimensional requirements of DIN 125 Form A, the specification now superseded by the international standard ISO 7089. They provide a flat, wide bearing surface beneath the head of a bolt, screw or nut, spreading the clamping load evenly across the mating material and protecting it from surface damage, pull-through and stress concentration. Supplied in bright zinc plated carbon steel, they are stocked across the complete metric range from M3 up to M36, covering everything from light electronics and instrument work through to heavy structural and industrial fastenings.

Form A washers are the standard, non-chamfered flat washer profile used throughout general engineering, construction and DIY assembly. The zinc plated finish gives useful protection against surface rust and corrosion, making these washers a cost-effective everyday choice. Every size is manufactured to the 200 HV hardness class defined in ISO 7089, giving a firm, non-deforming bearing surface that keeps its shape under load and is suitable for use with hexagon bolts, screws and nuts up to and including property class 8.8.

Key Features

• DIN 125 Form A / ISO 7089 compliant: Dimensions manufactured to the DIN 125 Form A specification and its superseding ISO 7089 standard, so fit and tolerances are consistent and predictable across every size.
• Zinc plated steel construction: A durable carbon steel washer with a bright zinc plated finish, giving useful resistance to surface corrosion.
• 200 HV hardness class: Meets the standard 200 HV hardness rating for ISO 7089 washers, suitable for bolts, screws and nuts up to and including property class 8.8.
• Even load distribution: The flat, wide bearing face spreads the clamping force of the fastener over a larger area, reducing point loading, surface marking and the risk of the joint working loose under vibration.
• Complete metric size range: Stocked from M3 through to M36, so the correct washer is available for small electrical and instrument fixings right up to heavy structural bolts.
• Form A flat profile: A plain, non-chamfered washer for general-purpose use, giving a flush, even seat under the fastener head or nut.

Technical Specifications Table

The table below lists the full dimensional specification for every stocked size, taken from the DIN 125 Form A / ISO 7089 standard. d1 is the inner (clearance hole) diameter, d2 is the outer diameter, and h is the washer thickness. Metric figures are in millimetres (mm); the final column gives the approximate nominal dimensions converted to inches (d1″ / d2″ / h″) for reference.

Note: ISO 7089 covers normal-series plain washers from M1.6 up to M64, so the M3–M36 range stocked here sits well within the scope of the standard. Tolerances shown are the standard min/max figures for each dimension.

Typical Applications

DIN 125 Form A / ISO 7089 flat washers are one of the most widely used fastener accessories, and are found wherever a bolted or screwed joint needs a flat, even bearing surface. Common uses include:

• General engineering and machine assembly, where a consistent bearing surface protects components from marking and uneven load.
• Automotive and workshop repairs, using the correct washer to match bolt and screw sizes on vehicles and equipment.
• Construction and structural fixings, spreading clamping load across timber, steel or masonry surfaces.
• Electrical enclosures, cabinets and panel building, where smaller sizes (M3–M6) are used with fixing screws.
• Furniture assembly, shelving and general joinery.
• General DIY, maintenance and repair tasks around the home, garage and workshop.

The zinc plated finish suits workshop, garage, structural and general trade applications.

Fitting Guidance

A few practical points help get the best performance and longest service life from a flat washer:

• Match the washer to the fastener: Select the washer size that corresponds to the nominal thread diameter of the bolt or screw being used (for example, an M8 washer for an M8 bolt) so the clearance hole gives a close, accurate fit without excessive play.
• Position correctly in the joint: Fit the washer under the bolt head or nut, whichever is being torqued or rotated during tightening, so it can do its job of spreading load and protecting the surface as the joint is drawn up.
• Check bolt grade compatibility: These 200 HV washers are suitable for use with hexagon bolts, screws and nuts up to and including property class 8.8.
• Avoid stacking washers: Use a single washer of the correct thickness rather than stacking multiple thinner washers, which can reduce joint stability and clamp force retention under vibration.
• Mind mixed-metal contact: When fastening onto stainless steel, aluminium or other dissimilar metals in damp conditions, be aware that zinc plated steel can be prone to galvanic corrosion over time.
• Store correctly: Keep washers dry between use to preserve the zinc plated finish, particularly for smaller sizes with thinner plating.