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M3 nut size
5.5 mm wrench
wrench size for M3 hex nut
M3 hex nut — standard metric hexagonal nut.
Full specification
| System | Metric |
| Nominal diameter | 3 mm |
| Wrench size (across flats) | 5.5 mm |
| Nut thickness | 2.4 mm |
| Common grade / class | Class 8 |
About M3 nuts
M3 hex nuts are standard metric hexagonal nuts used with M3 bolts and threaded rods.
The wrench size 5.5 mm is measured across the flats of the hexagon. The nut thickness is 2.4 mm.
Class 8 indicates the strength rating. These nuts are suitable for general-purpose applications.
Frequently asked questions
- What size wrench fits M3 nut?
- M3 nut uses a 5.5 mm wrench.
- How thick is a M3 nut?
- A standard M3 hex nut is 2.4 mm thick.
- What is the difference between M3 nut classes?
- Class Class 8 indicates the strength rating. Higher numbers mean stronger nuts.