Non-Serrated Flange Nuts
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.
FAQs about Non-Serrated Flange Nuts
Use the accordion below for quick answers on sizing, materials, installation, and best practices.
They combine a hex nut with a built-in washer. The smooth, wide flange spreads load over a larger area to protect the joint and help prevent pull-through, without biting into the surface.
Use non-serrated when you need to protect paint/plating, are clamping softer materials, or expect to loosen/retighten the joint. Choose serrated for added vibration resistance on metal-to-metal joints.
Usually no, the integrated flange provides the bearing surface. Add a flat washer only for oversized slots/holes, delicate finishes, or clearance requirements.
304 stainless works for most outdoor settings; 316 stainless is recommended for marine/coastal or chemical exposure. Zinc-plated steel is best for dry, indoor environments.
Match the bolt/stud thread system (inch or metric), diameter, and pitch. Also confirm the flange outside diameter and nut height fit your clearances and washers/slots.
Follow the torque specified for your bolt size/grade and lubrication condition. The smooth flange does not add prevailing torque; use standard torque values unless your spec says otherwise.
Yes, there’s no prevailing-torque feature to wear out. Inspect threads and bearing faces; replace if damaged or if your quality plan requires single-use.
Yes, this is a common reason to choose non-serrated. The smooth flange helps avoid gouging. Use appropriate washers/inserts as required by the design.
They rely on proper torque, friction, and thread engagement—not serrations. For high-vibration service, consider thread-locking methods (adhesive, prevailing-torque nuts, or serrated versions if surface marking is acceptable).
Offerings commonly follow inch commercial specs and metric DIN/ISO (e.g., DIN 6923 non-serrated variants). Verify the required standard and class on your drawing before ordering.