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M6 bolt size
10 mm wrench
across-flats spanner / socket size for M6
M6 bolt — Automotive, machinery, structural light duty.
Full specification
| System | Metric coarse |
| Nominal diameter | 6 mm |
| Thread pitch | 1.0 mm |
| Wrench / spanner (across flats) | 10 mm |
| Tap drill | 5.0 mm |
| Clearance hole | 6.6 mm |
| Common grade / class | 8.8 |
| Typical torque | 12 Nm (8.85 ft·lb) |
| Closest other-system size | ~1/4 inch |
🔧 Torque unit converter
Pre-filled with the typical torque for M6 (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 M6
Automotive, machinery, structural light duty.
A 5.0 mm tap drill is correct for M6 coarse thread. The standard clearance hole is 6.6 mm.
M6 is part of the ISO metric coarse thread series, defined in ISO 261. The wrench size 10 mm is measured across the flats of the hex head.
Common applications
M6 bolts are widely used in:
- Automotive, machinery, structural light duty
- General machinery and equipment assembly
- Automotive components and repairs
- Structural connections (when specified by engineer)
- Furniture and fixture assembly
Material and grade information
The typical grade for M6 is 8.8. This indicates:
- Property class 8.8: Medium carbon steel, quenched and tempered
- Tensile strength: 800 MPa minimum
- Yield strength: 640 MPa minimum (0.2% proof stress)
- Common coatings: Zinc plated, hot-dip galvanized, or plain
Frequently asked questions
- What size wrench or spanner fits M6?
- M6 bolt uses a 10 mm wrench or spanner, measured across the flats of the hex head.
- What is the torque for M6?
- A typical tightening torque for M6 bolt in 8.8 on dry threads is about 12 Nm (8.85 ft·lb). Always confirm against the manufacturer spec for important joints.
- What thread pitch and tap drill does M6 use?
- M6 bolt has a thread pitch of 1.0 mm and uses a 5.0 mm tap drill, with a 6.6 mm clearance hole.
- What is M6 used for?
- M6 is commonly used in automotive, machinery, structural light duty. It is one of the most popular sizes in its category.
- What is the closest imperial size to M6?
- The closest imperial size to M6 is approximately ~1/4 inch, though they are not exactly interchangeable.