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M2 bolt size
4 mm wrench
across-flats spanner / socket size for M2
M2 bolt — tiny machine and electronics fastener.
Full specification
| System | Metric coarse |
| Nominal diameter | 2 mm |
| Thread pitch | 0.4 mm |
| Wrench / spanner (across flats) | 4 mm |
| Tap drill | 1.6 mm |
| Clearance hole | 2.4 mm |
| Common grade / class | 8.8 |
| Typical torque | 0.4 Nm (0.3 ft·lb) |
| Closest other-system size | ~#2 imperial |
🔧 Torque unit converter
Pre-filled with the typical torque for M2 (8.8, dry). Edit any field to convert.
⚠️ Torque values here are general references for 8.8 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 M2
M2 is one of the smallest common metric bolts, used in electronics, optics and small enclosures.
Use a quality driver and very light torque — M2 threads strip easily in soft metals.
Frequently asked questions
- What size wrench or spanner fits M2?
- M2 bolt uses a 4 mm wrench or spanner, measured across the flats of the hex head.
- What is the torque for M2?
- A typical tightening torque for M2 bolt in 8.8 on dry threads is about 0.4 Nm (0.3 ft·lb). Always confirm against the manufacturer spec for important joints.
- What thread pitch and tap drill does M2 use?
- M2 bolt has a thread pitch of 0.4 mm and uses a 1.6 mm tap drill, with a 2.4 mm clearance hole.