Description
Overview
Screws are selected by head style, drive type, thread form, length, material and finish to suit the mating component and installation method.
This selected size is specified with diameter M8, length 40 mm, thread M8, pitch 1.25 mm.
Sold in multiples of '100 pieces. 1 Box = '100 pieces.
Material, Grade & Strength
Mild steel is an economical carbon steel option for general purpose fastening where high tensile strength is not required.
Finish & Corrosion Protection
Hot dip galvanising gives a heavier zinc coating for improved corrosion protection in outdoor or exposed conditions.
Typical Uses
Used in machinery, fabrication, construction, mining, agriculture, maintenance and general engineering where the selected size, material and finish match the application.
Technical Tips
- Confirm thread size, length, material and finish before ordering.
- Use compatible mating parts of suitable strength.
- For critical joints, follow recognised torque guidance.
- Choose corrosion-resistant material or finish for exposed environments.
Selection Advice
Select the product by matching the thread, size, material, finish and function to the assembly. Avoid choosing only by appearance or a partial part number.
Dimensions – DIN 558 / ISO 4018 M8 x 40
| Standard | DIN 558 / ISO 4018 |
|---|---|
| Product | Hexagon head set screw, product grade C |
| Thread | M8 x 1.25 |
| Length (l) | 40 mm |
| Across flats (s) | 13 mm |
| Head height (k) | 5.5 mm |
| Thread length (b) | full thread |
| Stress area (As) | 36.6 mm² |
| Weight (calculated) | 18.65 kg per 1 000 pieces |
Material, Grade & Strength
| Material | Mild steel (grade 4.6/4.8) |
|---|---|
| Property class | 4.6 / 4.8 (mild steel) |
| Tensile strength Rm (min) | 400 / 420 MPa |
| Yield strength (min) | 240 / 340 MPa |
| Proof load stress | 225 / 310 MPa |
| Matching nut | property class 5 (ISO 898-2) |
Finish & Corrosion Protection
Hot dip galvanised: Molten zinc coating, typically 40-55 um (ISO 10684). For outdoor, structural and agricultural use; nuts are tapped oversize to suit galvanised bolts, so use HDG nuts with HDG bolts.
DIN 558 data sheet – all sizes
| Size | Thread | Across flats (s) | Head height (k) | Thread length (b) | Stress area (As) |
|---|---|---|---|---|---|
| M3 | M3 x 0.5 | 5.5 mm | 2 mm | full thread | 5.0 mm² |
| M4 | M4 x 0.7 | 7 mm | 2.8 mm | full thread | 8.8 mm² |
| M5 | M5 x 0.8 | 8 mm | 3.5 mm | full thread | 14.2 mm² |
| M6 | M6 x 1 | 10 mm | 4 mm | full thread | 20.1 mm² |
| M7 | M7 x 1 | 11 mm | 4.8 mm | full thread | 28.9 mm² |
| M8 | M8 x 1.25 | 13 mm | 5.5 mm | full thread | 36.6 mm² |
| M10 | M10 x 1.5 | 17 mm (ISO: 16 mm) | 7 mm | full thread | 58.0 mm² |
| M12 | M12 x 1.75 | 19 mm (ISO: 18 mm) | 8 mm | full thread | 84.3 mm² |
| M14 | M14 x 2 | 22 mm (ISO: 21 mm) | 9 mm | full thread | 115.4 mm² |
| M16 | M16 x 2 | 24 mm | 10 mm | full thread | 156.7 mm² |
| M18 | M18 x 2.5 | 27 mm | 12 mm | full thread | 192.5 mm² |
| M20 | M20 x 2.5 | 30 mm | 13 mm | full thread | 244.8 mm² |
| M22 | M22 x 2.5 | 32 mm (ISO: 34 mm) | 14 mm | full thread | 303.4 mm² |
| M24 | M24 x 3 | 36 mm | 15 mm | full thread | 352.5 mm² |
| M27 | M27 x 3 | 41 mm | 17 mm | full thread | 459.4 mm² |
| M30 | M30 x 3.5 | 46 mm | 19 mm | full thread | 560.6 mm² |
| M33 | M33 x 3.5 | 50 mm | 21 mm | full thread | 693.6 mm² |
| M36 | M36 x 4 | 55 mm | 23 mm | full thread | 816.7 mm² |
| M39 | M39 x 4 | 60 mm | 25 mm | full thread | 975.8 mm² |
| M42 | M42 x 4.5 | 65 mm | 26 mm | full thread | 1120.9 mm² |
| M45 | M45 x 4.5 | 70 mm | 28 mm | full thread | 1306.0 mm² |
| M48 | M48 x 5 | 75 mm | 30 mm | full thread | 1473.1 mm² |
| M52 | M52 x 5 | 80 mm | 33 mm | full thread | 1757.8 mm² |
| M56 | M56 x 5.5 | 85 mm | 35 mm | full thread | 2030.0 mm² |
| M60 | M60 x 5.5 | 90 mm | 38 mm | full thread | 2362.0 mm² |
| M64 | M64 x 6 | 95 mm | 40 mm | full thread | 2676.0 mm² |
Nominal dimensions per DIN 558 / ISO 4018. Weights are calculated from nominal dimensions and are a guide only (±10%). Values for fit and strength should be confirmed against the standard for critical applications.
Specifications
| Measurement Type | Metric |
|---|---|
| Thread Size | M8 |
| Thread Pitch | 1.25 mm |
| Thread Style | Fully Thread |
| Drive Size | 13 mm |
| Drive Type | External Hex |
| Head Style | Hex |
| Diameter | M8 |
| Length | 40 mm |
| Material | Mild Steel |
| Finish | Hot Dip Galvanized |
| Grade | Grade 4.6 |
| Standards Met | SABS - ISO 1461 |
| Package Quantity | 100 |
| Package Type | Box |