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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.