Machine Screw Sizes & Head Types

Machine screws are available in various sizes and head types to accommodate a wide range of applications. The size and head type you choose depend on factors such as the type of material you're fastening, the required torque, and aesthetic preferences. Here are common machine screw sizes and head types:

Machine Screw Sizes: Machine screw sizes are typically specified using a number system for imperial screws or a metric system for metric screws.

Imperial (Inch) Machine Screw Sizes:

1. #0-80 to #12-24: These are smaller machine screw sizes, often used in precision instruments and electronics.
2. 1/4-20, 5/16-18, 3/8-16: These are larger machine screw sizes, frequently used in heavy machinery and construction.

Metric Machine Screw Sizes:

1. M1.0 to M10: These are smaller metric machine screw sizes, commonly used in electronics and small appliances.
2. M12 to M24: These are larger metric machine screw sizes, suitable for larger machinery and structural applications.

Machine Screw Head Types: Machine screws come in various head types, each with its own characteristics and uses.

1. Flat Head (Countersunk): Designed to sit flush with the surface when fully tightened, providing a smooth finish.
2. Pan Head: Rounded top with a flat underside, often used when a slightly raised or decorative appearance is desired.
3. Round Head: Semi-spherical top for a neat and finished look.
4. Truss Head: Low, rounded top with a wide, flat underside, offering increased strength and bearing surface.
5. Hex Head (Hexagonal): Six-sided head, requiring a wrench or socket for installation, known for high torque capability.
6. Phillips Head (Cross Recessed): Cross-shaped indentation on the top, requiring a Phillips screwdriver.
7. Slotted Head (Flathead): Single straight groove on top, requiring a flat-blade screwdriver.
8. Socket Head (Allen or Hex Socket): Cylindrical head with a hexagonal socket, requiring an Allen wrench or hex key.
9. Torx (Star) Head: Six-pointed star-shaped socket, requiring a Torx driver for installation, offers increased torque capability.
10. Security/Tamper-Resistant Heads: Designed to deter tampering, requiring specialized tools for installation, such as Torx with a pin (Tamper Torx) or a spanner.

The choice of machine screw size and head type should consider the specific requirements of your application. Factors to consider include load-bearing capacity, ease of installation, resistance to tampering, and aesthetic considerations. Always ensure that the size and head type of the machine screw are appropriate for your intended use and compatible with the corresponding nuts or threaded holes.