Description
Washer M16-A4 16×30 Steel Grade A ISO 7089 — BOLTON SKU 56367.
About the Washer M16-A4 16×30 Steel Grade A ISO
This washer is produced to ISO 7089, the normal-series flat-washer standard without chamfer, in product grade A. In the M16 size the standard defines a 17 mm clearance hole, a 30 mm outside diameter and a nominal thickness of 3 mm — the 16×30 figures quoted in the designation. A4 identifies an austenitic, acid-resistant stainless steel suited to joints where corrosion resistance has to match that of A4 bolts and nuts. Under an M16 fastener the washer distributes clamping force over a wider bearing surface, reduces embedment of the bolt head into the clamped part and protects finished surfaces while the joint is torqued. Product grade A gives the closer dimensional tolerances of the standard, and the washer serves identically under the bolt head or on the nut side of the joint.
Key specifications
| Standard | ISO 7089 (plain washer, normal series, without chamfer) |
|---|---|
| Product grade | A |
| Nominal size | M16 |
| Inside diameter (d1) | 17 mm |
| Outside diameter (d2) | 30 mm |
| Thickness (h) | 3 mm nominal (2.7–3.3 mm) |
| Material | A4 austenitic stainless steel |
| Cross-reference | DIN 125-1 Form A |
Typical applications
The M16 variant supports larger structural and machinery joints — base frames, lifting-frame hardware, heavy brackets and flange connections assembled with M16 A4 fasteners in coastal or wash-down environments. It is routinely paired with A4 hex bolts and nuts so the whole fastener stack shares one corrosion class.
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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