M4 External Tooth Lock Washer, 316 Stainless Steel - ELWA4M4

The External Serrated Tooth Lock Washer, A4 (316) Stainless Steel is a washer with teeth around its outer edge. The teeth bite into both the fastener and the surface to resist loosening.

The range runs to 7 variants, covering sizes M3 to M12. Variants are supplied in packs of 100 to 500, depending on size.

Made from 316 (A4) stainless steel, the grade normally specified for chloride-exposed work such as coastal installations, swimming pools, marine fittings and food-processing plant. Metric sizes are written M followed by the nominal thread diameter in millimetres, so M10 is a 10 mm thread.

In wet conditions, keep stainless steel apart from aluminium and galvanised steel with a washer or sleeve, to reduce the risk of galvanic corrosion.

Where this product is used

• Swimming pool and spa equipment
• Bulk jobs and trade or maintenance stores buying in larger packs
• Panels, frames and equipment subject to vibration
• Under bolt heads and nuts where a locking washer is needed
• Larger sizes for frames, plant and structural fixings
• Electrical and earthing connections

Features

• Resists loosening under vibration
• Teeth around the outer edge bite into the surface
• Metric thread sizes match the nuts, bolts and tapped holes in most Australian-supplied equipment
• A4 (316) stainless steel with molybdenum, for coastal and chloride-exposed settings
• Range covers M3 to M12 in 7 variants
• Pack quantities to suit trade and bulk buying: packs of 100 to 500

Key specifications

Selecting the right option

Teeth mark the surface they bite into, so avoid them on finished or painted faces. External teeth give a larger outer diameter than internal teeth for the same screw size, which suits bolt heads and nuts. For indoor and general outdoor use where chlorides are not a concern, the A2 (304) version is the lower-cost option: Metric External Tooth Lock Washer - 304 Stainless Steel.