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When your 3D printer, RC build, or precision assembly demands fasteners that won't strip, cam out, or corrode, standard hardware-store screws fall short. This 282-piece M3 socket head cap screw and nut kit is engineered for builders who need reliable, high-tensile fasteners across a wide range of lengths in a single organized set.
The kit includes M3 socket head cap screws in 10 lengths — 3 mm through 20 mm (approximately 1/8" to 3/4") — plus matching M3 hex nuts, all manufactured from 12.9 grade carbon steel with a black oxide finish. Each size is individually bagged and stored in a compartment case for quick access and zero mix-ups.
Ideal for 3D printer frame assembly, electronics enclosure mounting, bicycle component repair, communication equipment, and general home workshop use where metric M3 fasteners and a DIN 912 hex socket drive are required.
| Item | Size | Quantity |
|---|---|---|
| M3 Socket Head Cap Screw | M3 × 3 mm | See variant label |
| M3 Socket Head Cap Screw | M3 × 4 mm | See variant label |
| M3 Socket Head Cap Screw | M3 × 5 mm | See variant label |
| M3 Socket Head Cap Screw | M3 × 6 mm | See variant label |
| M3 Socket Head Cap Screw | M3 × 8 mm | See variant label |
| M3 Socket Head Cap Screw | M3 × 10 mm | See variant label |
| M3 Socket Head Cap Screw | M3 × 12 mm | See variant label |
| M3 Socket Head Cap Screw | M3 × 16 mm | See variant label |
| M3 Socket Head Cap Screw | M3 × 18 mm | See variant label |
| M3 Socket Head Cap Screw | M3 × 20 mm | See variant label |
| M3 Hex Nut | M3 | See variant label |
| Total Pieces | 282 Pcs | |
| Storage | 1× Compartment case with individual size bags | |
M3 is the dominant fastener size in FDM printer frames (Voron, Prusa, Ender series). Having all lengths on hand eliminates mid-build delays when a specific screw length is missing.
Mounting PCBs, securing enclosure panels, and assembling rack hardware all rely on M3 socket head cap screws. The black oxide finish suits both functional and aesthetic enclosure builds.
Component adjustments, accessory mounts, and drivetrain hardware on bicycles and RC vehicles frequently call for M3 metric fasteners — this kit covers the full range of common lengths.
From furniture assembly to appliance repair, a well-stocked M3 assortment reduces trips to the hardware store and keeps projects moving without interruption.
| Thread Size | M3 |
|---|---|
| Grade | 12.9 |
| Material | Carbon Steel |
| Finish | Black Oxide |
| Head Style | Socket Head Cap (Cup Head) |
| Drive Style | Hex Socket (Allen) |
| Hex Key Size | M2.5 |
| Standard | DIN 912 |
| Available Lengths | 3, 4, 5, 6, 8, 10, 12, 16, 18, 20 mm |
| Nut Thread | M3 |
| System of Measurement | Metric |
| Color | Black |
| Total Quantity | 282 Pieces |
| Storage | Compartment case with individual size bags |
These M3 socket head cap screws use an M2.5 hex key (Allen wrench). A 2.5 mm hex driver is included in the kit specifications; ensure your driver is the correct size to avoid rounding the socket.
The black oxide finish provides moderate corrosion resistance, but carbon steel is not inherently rust-proof. For prolonged outdoor or high-humidity exposure, consider applying a light coat of oil or using stainless steel fasteners instead.
Grade 12.9 fasteners have a minimum tensile strength of approximately 1220 MPa, compared to 800 MPa for grade 8.8. This makes 12.9 screws significantly stronger and better suited for high-stress or precision-clamping applications such as 3D printer frames and mechanical assemblies.
The kit contains 282 pieces total across 10 lengths (M3 × 3 mm through 20 mm) plus M3 hex nuts. The exact per-length count is shown on the packaging label. Each size is individually bagged inside the compartment case.
Yes. M3 DIN 912 socket head cap screws are the standard fastener used in most open-source 3D printer designs including Voron, Prusa MK series, and Ender-based builds. The 12.9 grade provides the clamping force needed for frame extrusions and motor mounts.
Yes. The 12.9 grade carbon steel construction allows repeated installation and removal without significant thread deformation, provided the mating threads are in good condition and the screws are not overtorqued during installation.
DIN 912 is a German industrial standard (Deutsches Institut für Normung) that defines the dimensions and tolerances for socket head cap screws. It is widely adopted internationally and ensures dimensional compatibility with other DIN 912-compliant hardware and tooling.
