Description
PLAIN WASHER M4 ISO 7089 ISO7089 M4-A4 — BOLTON SKU 60704.
About the Plain Washer M4 ISO 7089 Stainless
This item is a plain (flat) washer for M4 fasteners manufactured to ISO 7089, supplied in A4 stainless steel as indicated by the M4-A4 designation on the record. ISO 7089 is the international standard for normal-series plain washers without chamfer: it fixes the inside diameter, outside diameter, thickness, tolerances and hardness classes for each nominal size, making parts interchangeable between qualified manufacturers. The washer distributes clamping load under a bolt head or nut, protects the mating surface during tightening and covers clearance holes. A4 is the acid-proof austenitic stainless grade (316 type), alloyed with molybdenum for enhanced resistance to chlorides and aggressive atmospheres, which makes A4 hardware the usual choice for marine, coastal and chemically exposed installations. ISO 7089 corresponds to the traditional DIN 125A flat-washer pattern that much legacy documentation still references.
Key specifications
| Type | Plain (flat) washer, normal series, without chamfer |
|---|---|
| Standard | ISO 7089 |
| Nominal size | M4 |
| Material | Stainless steel A4 (per designation M4-A4) |
Typical applications
M4 flat washers are used in small mechanical and electronics assembly — enclosures, brackets, instrument mounting and UAV structures. A4 stainless versions suit corrosion-exposed and coastal service, and are stocked as standard MRO hardware.
Supplied by BOLTON Technical Equipment Supplies against request for quotation. Add this item to your RFQ basket to request pricing, lead time and documentation requirements (e.g. CoC, datasheets or test reports where applicable).
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