Hobson Metric Hex Set Screw, M8 / 55

The Hobson metric hex set screw has a hex head and a metric thread, and is fitted into a tapped hole or through a clearance hole with a nut (Class 8.8, zinc plated). There are 165 items: M5 to M30, in lengths from 12 to 300mm. Class 8.8 is high tensile, and corresponds to imperial grade 5.

Where this product is used

• Clamping brackets and plates to machine frames that already have threaded holes
• Fixing through a clearance hole with a nut where a fully threaded bolt suits the joint
• Replacing set screws of the same thread form, diameter and length
• Dry-environment assemblies where a zinc plated finish is enough protection
• Machinery, frames and equipment where a high tensile bolt is specified
• Choosing between the 165 items here: they cover diameters from M5 to M30 and lengths from 12mm to 300mm

Features

• 165 items: M5 to M30
• Class 8.8, zinc plated
• Length 12 to 300mm
• Zinc plated finish, for indoor and sheltered locations
• High tensile, medium-carbon steel in class 8.8

Key specifications

Choosing the right option

Choose the thread form first: the screw and the nut or tapped hole must match in thread form, diameter and pitch. Length is measured from under the head to the end of the screw. For a different strength level see Hobson Metric Hex Set Screw, Class 4.6 UTS, Plain, M16, M20 and M24.

A zinc plated finish gives light corrosion protection indoors and under cover. The coating is thin, so outdoor exposure without extra protection is generally not recommended, and treated pine calls for a different finish. Keep zinc plated parts for the dry side of the job, and use hot dip galvanised or 316 stainless where moisture, weather or salt air are involved.

Grade 8.8 is high tensile steel (medium carbon), and each size shows its minimum tensile strength. Choose it where a 4.6 mild steel bolt would be too light for the job. For load-critical, structural or lifting joints, confirm the fastener against the engineer's specification. Fasteners are not lifting rated unless marked.

Related items: Hobson Metric Hex Set Screw, Class 4.6, Mild Steel, Zinc Plated, M6 to M16, Hobson Metric Hex Set Screw, Class 10.9, Zinc Plated, M6 to M36 and Hobson Metric Hex Set Screw, Class 8.8, Hot Dip Galvanised, M24 x 170mm, Pack of 4.