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M6 set screw size
3 mm hex key
Allen / internal hex key size for M6 grub
M6 set screw — couplings and shaft collars.
Full specification
| System | Metric (45H) |
| Nominal diameter | 6 mm |
| Thread pitch | 1.0 mm |
| Hex key (Allen) | 3 mm |
| Tap drill | 5.0 mm |
| Clearance hole | n/a (threaded) |
| Common grade / class | 45H |
| Typical torque | 5.8 Nm (4.3 ft·lb) |
| Closest other-system size | ~1/4 inch |
🔧 Torque unit converter
Pre-filled with the typical torque for M6 grub (45H, dry). Edit any field to convert.
⚠️ Torque values here are general references for 45H 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 grub
M6 grub screws are common in shaft collars and couplings.
A cup-point M6 grub bites into the shaft for the strongest hold.
Frequently asked questions
- What size Allen / hex key fits M6 grub?
- M6 set screw uses a 3 mm hex (Allen) key with an internal hex drive.
- What is the torque for M6 grub?
- A typical tightening torque for M6 set screw in 45H on dry threads is about 5.8 Nm (4.3 ft·lb). Always confirm against the manufacturer spec for important joints.
- What thread pitch and tap drill does M6 grub use?
- M6 set screw has a thread pitch of 1.0 mm and uses a 5.0 mm tap drill, with a n/a (threaded) clearance hole.