Cap & Acorn Nuts vs. Flange Nuts
Comparing 2 standards across 10 specifications. 10 key differences identified.
Cap and Acorn nuts (standardized under DIN 1587 and ASME B18.2.2) feature a domed, blind-ended crown that completely encloses the protruding end of a mating screw or threaded rod. They prevent snagging on clothing, protect exposed threads from corrosion and moisture, and provide a finished decorative appearance on consumer goods, bicycles, and furniture.
The Flange Nut (standardized under DIN 6923 and ISO 4161) is a hexagonal nut featuring an integrated wide, circular washer-like flange base. Available in smooth and serrated locking variants, it distributes clamping pressure over a larger surface area and eliminates the need for separate flat washers in high-speed automotive and industrial assembly.
Specification Comparison Table
10 Parameters| Parameter / Spec | ||
|---|---|---|
|
Standard Specifications
|
DIN 1587 (High type dome) / DIN 917 (Low profile cap) / ASME B18.2.2 | DIN 6923 / ISO 4161 / ASME B18.16.4 |
|
Primary Applications
|
Bicycle axle hubs, motorcycle engine covers, outdoor playground structures, furniture | Automotive exhaust and chassis, bicycle axle nuts, solar panel racking, sheet metal framing |
|
Dome Profile
|
Hemispherical blind cap permanently enclosing internal tapped threads | — |
|
Safety Function
|
Eliminates sharp exposed screw threads that cause lacerations or fabric snags | — |
|
Environmental Protection
|
Seals internal thread engagement from weather, road salt, and industrial grime | — |
|
Common Materials
|
A2/A4 Stainless steel, solid brass, chrome-plated steel, black oxide steel | — |
|
Flange Diameter Ratio
|
— | Flange Base Diameter ≈ 2.0× to 2.2× Thread Diameter |
|
Bearing Surface Variants
|
— | Smooth Flange (load spreading) or Serrated Flange (mechanical anti-backoff teeth) |
|
Serration Angle
|
— | Angled teeth that allow clockwise tightening but bite into metal during counter-clockwise loosening |
|
Property Classes
|
— | Class 8, Class 10 (ISO 898-2) / Grade 5, Grade 8 (Imperial) |