The diameter of an M3 screw is 3 millimeters (mm).
Understanding Metric Screw Sizing
In the metric system, screw sizes are designated with an "M" followed by a number. This number directly indicates the nominal major diameter of the screw's threads in millimeters. This straightforward naming convention makes it easy to understand the primary dimension of a metric fastener.
For instance:
- An M3 screw has a nominal diameter of 3mm.
- An M4 screw has a nominal diameter of 4mm.
- An M5 screw has a nominal diameter of 5mm.
This pattern holds true for all standard metric screws, where the number after the 'M' signifies the outer diameter of the threads.
Key Characteristics of M3 Screws
Beyond their 3mm diameter, M3 screws are widely used due to their versatility and compact size. While the question specifically asks about diameter, it's helpful to understand other common aspects:
- Nominal Diameter: 3mm
- Standard Thread Pitch: The most common thread pitch for M3 screws is 0.5mm (coarse pitch). This refers to the distance between two adjacent threads.
- Material: M3 screws are available in various materials, including stainless steel, carbon steel, brass, and nylon, depending on the required strength, corrosion resistance, and application.
- Head Types: They come in numerous head styles such as Phillips, flat head, pan head, socket cap, button head, and more, each suited for different applications and aesthetics.
Common Applications of M3 Screws
M3 screws are a staple in many industries and household applications due to their precise sizing and reliability. Their size makes them ideal for securing smaller components.
- Electronics: Widely used in circuit boards, computer components, and small electronic devices.
- Consumer Goods: Found in toys, cameras, glasses, and other small appliances.
- 3D Printing: Essential for assembling 3D printer frames and components.
- Model Making: Popular in robotics, RC vehicles, and intricate model assemblies.
- Enclosures and Panels: Used for mounting components to panels or securing small enclosures.
Table of Common Metric Screw Diameters
To further illustrate the metric sizing system, here's a table of common nominal diameters:
| Metric Designation | Nominal Diameter (mm) |
|---|---|
| M2 | 2 |
| M2.5 | 2.5 |
| M3 | 3 |
| M4 | 4 |
| M5 | 5 |
| M6 | 6 |
| M8 | 8 |
| M10 | 10 |
Understanding these standard sizes is crucial for selecting the correct fasteners for any project. For more detailed information on various fastener types and their specifications, you can consult a comprehensive fastener guide.
