120 mm Cup Head Square Neck Bolt, 316 Stainless Steel - CHBA4M8X120

The Cup Head Square Neck Bolt M8, 316 Stainless Steel is a domed (cup) head bolt with a square section under the head. The square neck seats in a square hole or bites into timber so the bolt does not turn while the nut is tightened. It is also called a carriage bolt.

A4 (316) stainless steel contains molybdenum (about 2 to 3 per cent), which improves its resistance to chlorides. It is the grade normally chosen for coastal, pool, marine and food-processing settings, and it costs more than A2 (304). Metric sizes are written M followed by the nominal thread diameter in millimetres, so M10 is a 10 mm thread.

You can choose from 3 variants, covering lengths 120 mm to 150 mm. Each variant is supplied in packs of 50.

Stainless threads can gall (seize) when tightened under load or at speed. A smear of anti-seize on the thread and a steady tightening speed reduce the risk.

Where this product is used

• Swimming pool and spa equipment
• Boat trailers, jetties and coastal timber work
• Timber fencing, decking frames and pergolas
• Food and beverage processing equipment
• Playground and outdoor furniture, where a smooth domed head faces out

Features

• Pack quantities to suit trade and bulk buying: packs of 50
• Smooth domed head with no tool recess to catch on
• Lengths from 120 mm to 150 mm
• 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
• Square neck locks into timber or a square hole

Key specifications

Selecting the right option

Drill the hole to the bolt diameter, then pull the square neck into the timber with the nut. Use a flat washer under the nut. The bolt length should cover the timber thickness plus the washer and nut with at least one thread showing.

Related products

Also available: Metric Cup Head Square Neck Bolt - 316 Stainless Steel. Matching products: Metric Standard Hex Nut - 316 Stainless Steel, Metric Hex Nylon Insert Lock Nut - 316 Stainless Steel and Flat Round Washer DIN125A Stainless Steel.