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M3 socket cap screw size
2.5 mm hex key
Allen / internal hex key size for M3 socket cap
M3 socket cap screw — electronics, jigs and 3D printers.
Full specification
| System | Metric (12.9) |
| Nominal diameter | 3 mm |
| Thread pitch | 0.5 mm |
| Hex key (Allen) | 2.5 mm |
| Tap drill | 2.5 mm |
| Clearance hole | 3.4 mm |
| Common grade / class | 12.9 |
| Typical torque | 2 Nm (1.5 ft·lb) |
| Closest other-system size | ~#5 imperial |
🔧 Torque unit converter
Pre-filled with the typical torque for M3 socket cap (12.9, dry). Edit any field to convert.
⚠️ Torque values here are general references for 12.9 on clean, dry threads. Lubrication, coatings, and the joint material change the figure significantly. For structural, automotive, or safety-critical work, always use the torque specified by the manufacturer or engineer.
About M3 socket cap
M3 socket cap screws are everywhere in 3D printers, jigs and small machines.
A 2.5 mm hex key drives M3 cap screws — keep a ball-end set for awkward angles.
Frequently asked questions
- What size Allen / hex key fits M3 socket cap?
- M3 socket cap screw uses a 2.5 mm hex (Allen) key with an internal hex drive.
- What is the torque for M3 socket cap?
- A typical tightening torque for M3 socket cap screw in 12.9 on dry threads is about 2 Nm (1.5 ft·lb). Always confirm against the manufacturer spec for important joints.
- What thread pitch and tap drill does M3 socket cap use?
- M3 socket cap screw has a thread pitch of 0.5 mm and uses a 2.5 mm tap drill, with a 3.4 mm clearance hole.