Phillips Hex Flange Screws 304 Stainless Steel M3–M8 | Dentate & Flat Flange

Dentate (serrated) flange screws have small teeth on the underside of the flange that bite into the mating surface as the screw is tightened, creating a mechanical locking effect that resists loosening under vibration. This makes them well-suited for machinery, automotive, and equipment applications where vibration is a concern. Flat flange screws have a smooth flange underside, providing a larger, cleaner bearing surface without the anti-loosening teeth — preferred when surface finish matters, when using a separate locking washer, or when the mating surface is too hard for the teeth to engage effectively.

A general rule of thumb is that the screw should engage at least 1.5× the thread diameter in the receiving material. For example, an M4 screw (4mm diameter) should generally have at least 6mm of thread engagement in the tapped hole or nut. For through-bolt applications, measure the total thickness of all materials being clamped and add the required thread engagement depth. Available lengths range from 5mm (≈3/16") to 60mm (≈2-3/8") depending on the thread size — see variant options for the full range by size. When in doubt, choose a slightly longer screw and use a nut or threaded insert to control engagement depth.

304 stainless steel provides significantly better corrosion resistance than carbon steel or zinc-plated fasteners, making it suitable for humid, wet, and mildly corrosive environments where carbon steel would rust and zinc plating would eventually fail. It also maintains its appearance over time without surface coatings that can chip, flake, or contaminate sensitive assemblies. For most indoor and outdoor applications (excluding marine or highly chloride-rich environments), 304 stainless is generally a reliable long-term choice that eliminates the need for periodic re-coating or replacement due to rust.

Yes, 304 stainless steel generally provides good corrosion resistance for outdoor and wet environments, including rain exposure, humidity, and mild chemical contact. It is commonly used in outdoor fixtures, garden equipment, food-service equipment, and architectural applications. However, for marine environments or applications with prolonged exposure to saltwater or chloride-rich conditions, 316 stainless steel is typically recommended instead, as 304 can develop surface staining (tea staining) or pitting in high-chloride environments over time.

Yes, these screws use standard ISO metric coarse thread profiles and are compatible with standard metric nuts, threaded inserts, and tapped holes of the corresponding size. Standard coarse thread pitches apply: M3×0.5, M4×0.7, M5×0.8, M6×1.0, M8×1.25. They are not compatible with fine-thread nuts or tapped holes of the same nominal diameter. Contact us to confirm if your application requires fine thread.

304 stainless steel fasteners typically have a tensile strength of approximately 500–700 MPa depending on the specific grade and manufacturing process, which is generally suitable for light to medium structural loads in non-critical applications. The integrated flange also helps distribute clamping load, reducing stress concentration at the fastener head. For safety-critical, high-load, or structural applications, consult an engineer and verify the specific mechanical properties required. Contact us to confirm if your application has specific load or torque requirements.

Yes, these screws can be installed with a power driver using a Phillips bit (PH2 is typically appropriate for M4–M8; PH1 for M3). The hex head also allows use of a hex socket or wrench for higher torque applications or when a Phillips bit would cam out. When using a power driver, apply moderate torque and avoid over-tightening, which can strip the Phillips drive or damage the mating threads. A torque wrench is recommended for critical applications where specific clamping force is required.