Hobson Metric Button Head Socket Screw, M4 / 8mm

The Hobson metric button head socket screw has a metric thread and is alloy steel, zinc finish, grade 12.9. There are 56 items: M4 to M12, in lengths from 8mm to 100mm. Head style: BHCS, Button Head Cap Screw.

The head is low and domed, with a socket drive. This item is Grade 12.9. It changes with the size and length.

Where this product is used

• Low-profile fixing where a smooth rounded head is wanted, such as guards, covers and panels
• Machine guards and enclosures where a rounded head will not snag clothing or hands
• Light-duty fixing where the taller head of a cap screw would be in the way
• Dry, indoor and sheltered locations such as workshops, enclosed machinery and interior fit-out
• Heavy-duty, high-load assemblies in machinery and equipment
• Choosing between the 56 items here: they cover diameters from M4 to M12 and lengths from 8mm to 100mm

Features

• 56 items: M4 to M12
• Metric thread, button head socket screw
• Alloy steel
• Zinc finish
• Zinc plated finish, for indoor and sheltered locations
• Class 12.9 alloy steel for heavy-duty, high-load work

Key specifications

Choosing the right option

Choose the thread form first: the screw must match its nut or tapped hole in thread form, diameter and pitch.

Zinc plating suits workshops, enclosed machinery and interior fit-out. Because the electroplated coating is thin, it is generally unsuitable for outdoor exposure and does not meet treated-timber requirements (not suitable for treated pine). For weather-exposed work, look at a hot dip galvanised version instead; within about 1 km of the sea, 316 stainless is generally the safer choice. Because electroplating can cause hydrogen embrittlement in high-strength steel, high-strength zinc plated fasteners are baked after plating.

Class 12.9 is alloy steel for heavy-duty, high-load assemblies, with the minimum tensile strength shown against each size. For load-critical, structural or lifting joints, confirm the fastener against the engineer's specification. Fasteners are not lifting rated unless marked.

Related socket screws: Hobson Metric Button Head Socket Screw, Alloy 12.9, Plain, M5 and M16, Hobson Metric Button Head Socket Screw, Alloy 12.9, Zinc Plated, M5 to M12 and Hobson Metric Button Head Socket Screw, Class 10.9, Zinc Plated, M6 to M12.