Hobson Metric Hex Bolt and Nut, M20 / 55mm

The Hobson metric hex bolt and nut range has 178 items in class 8.8, plain finish: sizes M6 to M36, with lengths from 16mm to 300mm. Class 8.8 is high tensile, and corresponds to imperial grade 5.

Where this product is used

• Fixing timber to steel through a drilled hole, with a flat washer under the head and the nut
• Machinery guards, frames and conveyor supports that are bolted rather than welded
• Replacing a bolt and nut pair of the same thread form and diameter
• Workshop jobs where the part is protected by its surroundings
• Machinery, frames and equipment where a high tensile bolt is specified
• The 178 items cover diameters from M6 to M36 and lengths from 16mm to 300mm, confirm the size against your drawing before ordering

Features

• 11 sizes: M6 to M36
• Class 8.8, Plain finish
• Lengths from 16mm to 300mm
• Pack quantity and part number for every item
• Proof load and minimum tensile strength
• Spanner size (A/F) by size
• Plain finish: suited to dry indoor, oiled, painted or enclosed use
• High tensile, medium-carbon steel in class 8.8

Key specifications

Choosing the right option

Choose the thread form first: the nut must match the bolt in thread form, diameter and pitch. Length is measured from under the head to the end of the bolt. For the bolt on its own: see Hobson Metric Hex Bolt, Class 8.8, Plain, M6 to M36 x 16 to 300mm.

Plain (uncoated) steel has no corrosion protection beyond a light oil film, and it rusts quickly once moisture reaches it. Keep plain parts for dry indoor use, machinery and assemblies that get painted, oiled or enclosed. Outdoors or in damp areas, a hot dip galvanised or 316 stainless alternative is the better choice.

Class 8.8 is a high tensile, medium-carbon steel class, with the minimum tensile strength shown against each size. It suits machinery, structural-style frames and general engineering work. For load-critical, structural or lifting joints, confirm the fastener against the engineer's specification. Fasteners are not lifting rated unless marked.

Related hex bolts: Hobson Metric Hex Bolt and Nut, Class 8.8, Plain, M6 to M36 x 60 to 400mm, Hobson Metric Hex Bolt, Class 8.8, Plain, M6 to M36 x 16 to 300mm and Hobson Metric Hex Bolt and Nut, Class 8.8, Hot Dip Galvanised, M8 to M16 x 20 to 50mm.