Hobson Metric Hex Bolt and Nut, M6 / 20mm

The Hobson metric hex bolt and nut range has 202 items (Class 4.6, hot dip galvanised): M6 to M36, in lengths of 20 to 750mm. Each item is a hex bolt supplied with a matching nut. Class 4.6 is low tensile carbon steel, and corresponds to imperial grade 2.

Spanner sizes are the width across flats (A/F), using its class 4.6/8.8 column. Pack quantity is shown for each item.

Where this product is used

• Fixing timber to steel through a drilled hole, with a flat washer under the head and the nut
• Trailer, fencing and shed framework where a bolted joint may need adjusting later
• Workshop and site kits where the nut should arrive with the bolt instead of being ordered separately
• Farm and rural fencing and other work that stays outside year-round
• General-purpose light fabrication, framing and non-critical joints

Features

• 202 items: M6 to M36, 20 to 750mm long
• Metric thread, hex head
• Class 4.6, hot dip galvanised
• Nut supplied with each bolt
• Pack quantity shown for each item
• Hot dip galvanised finish, for outdoor and weather-exposed work
• Class 4.6 general-purpose mild steel

Key specifications

Choosing the right option

Choose the thread form first: the bolt and its nut must match in thread form, diameter and pitch. Metric sizes are the nominal diameter in millimetres; compare the pitch shown for each item with your nut. Length is measured from under the head to the end of the bolt, so choose size and length together. The nut is supplied with each bolt. Spanner size is the width across flats of the head and nut.

Hot dip galvanised parts are the usual pick for work that stays outside for years, such as structural steelwork, roofing and fencing, because the zinc coating is thick. Close to the sea, within about 1 km, or in splash zones, 316 stainless is generally the better choice. Because a hot dip galvanised nut is tapped oversize after galvanising, galvanised bolts should be paired with galvanised nuts, not standard-tolerance nuts, in structural joints. Put a clean, dry-to-touch lubricant on the nut threads before tightening.

Property class 4.6 is general-purpose mild steel. It suits light fabrication and non-critical joints where strength is not the deciding factor. For load-critical, structural or lifting joints, confirm the fastener against the engineer's specification. Fasteners are not lifting rated unless marked.

Related bolts: Hobson Metric Hex Bolt and Nut, G4.6, Zinc, M6 to M20 x 20 to 150mm, Hobson Metric Hex Bolt, Class 4.6 UTS, Zinc Plated, M20 x 55 to 65mm and Hobson Metric Hex Bolt and Nut, G8.8, Zinc, M6 to M24 x 12 to 200mm.