Metric Zinc Plated Class 8.8 Steel Non-Serrated Flange Nuts
Metric Non-Serrated Flange Nuts—also called smooth flange nuts, plain flange nuts, washer face nuts, or free-spinning flange nuts—combine a standard hex nut with an integrated flat washer flange at the base. Unlike serrated flange nuts that grip and dig into surfaces, non-serrated flange nuts feature a smooth bearing surface that allows the nut to rotate freely during tightening without scratching, marring, or damaging the material underneath. This makes them the preferred choice for applications involving painted, powder-coated, anodized, or polished surfaces where surface protection is critical.
Why Choose Non-Serrated Flange Nuts?
The smooth flange design offers several advantages over standard hex nuts and serrated alternatives. The wider load-bearing surface distributes clamping force across a larger area, reducing stress concentration and preventing pull-through on softer materials like aluminum, plastic, fiberglass, and thin sheet metal. Because the flange acts as a built-in washer, these nuts eliminate the need for a separate flat washer—saving time during assembly, reducing part count, and lowering overall fastener costs. Free-spinning flange nuts are also easier to remove and reinstall without causing cumulative surface damage, making them ideal for applications requiring periodic maintenance or adjustment.
Material & Specifications
Our metric non-serrated hex flange nuts are manufactured from Class 8.8 steel, a high-strength medium carbon steel grade commonly used in automotive and industrial fastening applications. Class 8.8 provides a tensile strength of approximately 800 MPa (116,000 PSI) and yield strength of 640 MPa, offering excellent performance in demanding assemblies. The zinc plated finish provides corrosion resistance for indoor use and light outdoor exposure, while also facilitating smoother installation. Zinc plating meets RoHS compliance standards for environmentally responsible manufacturing.
Common Applications
Metric smooth flange nuts are used across a wide range of industries and applications, including:
- Automotive & Motorsports: Engine components, body panels, exhaust systems, suspension assemblies, interior trim
- Machinery & Equipment: Frame assemblies, guards, covers, access panels, conveyor systems
- HVAC & Mechanical: Ductwork, mounting brackets, equipment enclosures
- Electrical & Electronics: Control panels, junction boxes, equipment racks, enclosures
- General Assembly & Manufacturing: Any application where surface finish protection and even load distribution are required
Serrated vs. Non-Serrated Flange Nuts: Which Do You Need?
Choosing between serrated and non-serrated flange nuts depends on your application requirements. Serrated flange nuts feature teeth on the flange that bite into the mating surface, providing vibration resistance and locking action—but they will permanently mark the surface. Non-serrated (smooth) flange nuts allow free rotation and protect surface finishes but do not provide the same locking capability. If vibration resistance is needed with a smooth flange nut, consider using a thread locker compound or pairing with a separate lock washer.
Available Sizes
We stock metric non-serrated flange nuts in popular sizes to cover most common applications. Whether you need M5, M6, M8, M10, M12, or larger metric flange nuts, AlbanyCountyFasteners.com has you covered with competitive bulk pricing and same-day shipping on in-stock items.
Can't find the size you need? Contact our team—with over 18 million fasteners in stock, we can help you find the right metric flange nut for your project.