A
Anonymous
Mar 27, 2026
Rating: 5/5
Great Value
Better price than local hardware store and the grade is genuine 12.9.
Description
Grade 12.9 Black High-Strength Flat Head Socket Cap Screws M3 M4 M5 M6 M8 M10
Reviews
Attributes
| Brand | - |
| Category | Industrial Small Parts / Connectors and Fasteners |
| Origin | - |
| Material | Alloy Steel |
| Strength Grade | 12.9 |
| Surface Finish | Black Oxide |
| Head Style | Flat Head (Countersunk) |
| Drive Type | Hex Socket (Allen) |
| Thread Type | Coarse Metric |
| Size Range | M3, M4, M5, M6, M8, M10 |
| Hardness | 39-44 HRC |
| Standard | DIN 7991 / ISO 10642 |
| Package Type | Bulk Box |
5 reviews
A
Anonymous
Mar 03, 2026
Rating: 5/5
True to Size
Metric measurements are accurate. The countersunk head sits flush exactly as needed.
A
Anonymous
Feb 27, 2026
Rating: 4/5
Good Product
Solid screws, slight variation in black finish but does not affect performance.
A
Anonymous
Feb 25, 2026
Rating: 5/5
Excellent Strength
These bolts handled high tension without stripping. Perfect for my machinery repair project.
A
Anonymous
Feb 23, 2026
Rating: 5/5
Perfect for Machinery
Used on CNC equipment, no issues under vibration. High quality steel.
5 FAQ
Q: Are the threads full length?
A: Yes, these countersunk cap bolts are fully threaded along the shaft.
Q: What key size is needed for M8?
A: An M8 hex socket flat head screw typically requires a 6mm Allen key.
Q: Are these screws rust proof?
A: Black oxide provides limited protection against corrosion. They are not recommended for wet or outdoor environments.
Q: Do you have M12 size available?
A: Currently this listing is limited to sizes up to M10. Please check our other listings for larger diameters.
Q: Can I use these on aluminum parts?
A: Yes, but ensure you apply proper torque to avoid stripping the softer aluminum threads.
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