Product Description
M5 Class 12.9 Zinc-Plated Socket Cap Bolts
These M5 socket head cap bolts are manufactured from high-tensile class 12.9 steel and protected with a zinc-plated finish. Their cylindrical cap head and internal hexagon drive provide strong, compact fastening for machinery, equipment, automotive and general engineering applications.
Each bolt has a standard M5 × 0.8mm metric coarse thread and a partially threaded shank. The unthreaded section provides a solid bearing surface through the joined components, making these bolts suitable for applications involving alignment, shear loading or clamping through thicker assemblies.
Product Details
- Thread size: M5
- Thread pitch: 0.8mm metric coarse
- Available lengths: 30mm, 35mm, 40mm, 45mm, 50mm, 55mm, 60mm and 80mm
- Material: High-tensile steel
- Property class: 12.9
- Finish: Zinc plated
- Head style: Cylindrical socket cap head
- Drive type: Internal hexagon
- Required hex key: 4mm
- Thread coverage: Partially threaded with an unthreaded shank
- Current standard: BS EN ISO 4762:2004 / ISO 4762
- Legacy standard: DIN 912
- Mechanical-property standard: BS EN ISO 898-1
The selected length is measured from beneath the cylindrical head to the end of the bolt. The head is not included in the stated length.
Class 12.9 High-Tensile Steel
Property class 12.9 is designed for highly loaded engineering fasteners requiring high tensile and proof strength. The mating nut or tapped component, available thread engagement and tightening method must all be suitable for a class 12.9 fastener.
The zinc-plated finish provides additional corrosion protection compared with an untreated self-colour surface. It is intended for general engineering conditions and should not be treated as a substitute for stainless steel or a specialist coating in aggressive, marine or continuously wet environments.
Typical Applications
- Machinery and equipment assembly
- Automotive and motorsport components
- Jigs, fixtures and tooling
- Production and automation equipment
- Engineering brackets and frames
- Applications requiring a partially threaded shank
- Compact high-strength mechanical assemblies
Installation Guidance
Install using a correctly fitting 4mm hex key or socket bit. Ensure the mating thread is clean, correctly formed and provides sufficient thread engagement for the application.
Tightening torque depends on the joint design, coating, lubrication, mating materials and operating conditions. Use the torque specified by the equipment manufacturer or a suitably qualified engineer rather than applying a generic value.
Pack Quantities
Available individually or in packs of 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 50, 100, 250, 500 or 1,000 bolts, depending on the selected length.
View our complete range of metric socket cap screws.

| A | B | C | D | E | F | G | H |
| 5mm | 50mm | 22mm | 10mm | 2.8mm | 3mm | 0.8 | 28mm |
| 5mm | 60mm | 22mm | 10mm | 2.8mm | 3mm | 0.8 | 38mm |
| 5mm | 35mm | 22mm | 10mm | 2.8mm | 3mm | 0.8 | 13mm |
| 5mm | 40mm | 22mm | 10mm | 2.8mm | 3mm | 0.8 | 18mm |
| 5mm | 45mm | 22mm | 10mm | 2.8mm | 3mm | 0.8 | 23mm |
| 5mm | 55mm | 22mm | 10mm | 2.8mm | 3mm | 0.8 | 33mm |
| 5mm | 80mm | 22mm | 10mm | 2.8mm | 3mm | 0.8 | 58mm |
Please Note: Specifications given are intended as a guide only. If critical to your project please check with us first.