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M5 socket cap screw size
4 mm hex key
Allen / internal hex key size for M5 socket cap
M5 socket cap screw — machinery and bicycle parts.
Full specification
| System | Metric (12.9) |
| Nominal diameter | 5 mm |
| Thread pitch | 0.8 mm |
| Hex key (Allen) | 4 mm |
| Tap drill | 4.2 mm |
| Clearance hole | 5.5 mm |
| Common grade / class | 12.9 |
| Typical torque | 9.5 Nm (7 ft·lb) |
| Closest other-system size | ~#10 imperial |
🔧 Torque unit converter
Pre-filled with the typical torque for M5 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 M5 socket cap
M5 socket caps are common on machinery covers and bicycle components.
A 4 mm hex key drives M5 — the most-used size in many bike toolkits.
Frequently asked questions
- What size Allen / hex key fits M5 socket cap?
- M5 socket cap screw uses a 4 mm hex (Allen) key with an internal hex drive.
- What is the torque for M5 socket cap?
- A typical tightening torque for M5 socket cap screw in 12.9 on dry threads is about 9.5 Nm (7 ft·lb). Always confirm against the manufacturer spec for important joints.
- What thread pitch and tap drill does M5 socket cap use?
- M5 socket cap screw has a thread pitch of 0.8 mm and uses a 4.2 mm tap drill, with a 5.5 mm clearance hole.