What Are Non-Serrated Flange Nuts?
Non-serrated flange nuts are hex nuts with a wide, integrated flange that acts like a built-in washer. Unlike serrated versions, the bearing face is smooth, allowing the nut to clamp evenly without biting into the surface—ideal where finishes must be protected or frequent adjustment/removal is expected.
Key Benefits of Non-Serrated Flange Nuts
- Integrated washer – wide bearing surface spreads load and protects the joint.
- Finish-friendly – smooth face helps preserve paint, plating, and soft substrates.
- Serviceable – easier to reposition or remove than serrated locking styles.
- Fast installation – hex drive uses standard wrenches and sockets.
Materials & Finishes
- 18-8 / 304 Stainless Steel – general corrosion resistance for indoor/outdoor use.
- 316 Stainless Steel – superior corrosion resistance for marine, chemical, or coastal environments.
- Carbon Steel, Zinc Plated – economical protection for dry or sheltered settings.
- Metric A2/A4 (DIN/ISO) – common metric options for global builds.
When to Choose Non-Serrated vs. Serrated
- Choose non-serrated to protect coatings/finishes, on soft materials (aluminum, plastics, wood with inserts), or when joints are frequently adjusted.
- Choose serrated for added vibration resistance on metal-to-metal joints where minor surface marking is acceptable.
Common Applications
- Sheet-metal fabrication, enclosures, and guards
- Furniture, fixture, and display assemblies
- HVAC, MEP supports, and electrical equipment
- General machinery, racking, and light structural frames
Selection Guide
- Thread – match inch (UNC/UNF) or metric (coarse/fine), diameter, and pitch.
- Flange O.D. – verify it covers slots/oversize holes and fits recesses or clearances.
- Environment – pick stainless (304/316) for corrosion; zinc-plated steel for economical indoor use.
- Strength & spec – confirm the nut grade/standard required by your print or BOM.
Installation Tips
- Hand-start to avoid cross-threading; tighten with a correctly sized wrench/socket.
- Seat the smooth flange directly on the joint; use additional flat washers only when needed for clearance or surface protection.
- Follow torque specs for the bolt size/grade and lubrication condition.
- For stainless-to-stainless joints, consider anti-seize per spec to reduce galling risk.
Standards & Fit
Non-serrated flange nuts are produced to common inch and DIN/ISO metric standards with standard internal thread classes (e.g., 2B inch / 6H metric). Verify thread, flange diameter, and height against your drawings before assembly.