Stainless Steel Hex Socket Cylinder Nut Round Threaded Rod Nut

Description

What Are Cylinder Nuts?

A cylinder nut, also known as a barrel nut or round nut, is a type of specialty fastener characterized by its cylindrical (barrel-shaped) body instead of the standard hexagonal or square shape. This body is internally threaded to accept a bolt or threaded rod. Unlike a standard nut, a cylinder nut is typically designed to be inserted into a pre-drilled hole or a pocket within a structure, often where access to the sides of the nut is impossible. They are commonly used with a setscrew or a pin that engages with a keyway on the nut’s outer surface to prevent rotation during assembly, providing a strong, clean, and low-profile fastening solution.

Materials

Cylinder nuts are manufactured from various materials to meet different strength and environmental requirements:

• Carbon Steel: The most common and cost-effective material, used in general industrial applications. Often comes with a surface coating for corrosion protection.

• Alloy Steel: Used for high-strength applications, such as in automotive or aerospace sectors. These are often heat-treated.

• Stainless Steel: (e.g., 304 or 316 grade) Offers excellent corrosion resistance for use in harsh environments, food processing, marine, or medical applications.

• Aluminum: Chosen for its lightweight properties and good corrosion resistance, often used in aerospace and automotive industries.

• Brass: Primarily used for its corrosion resistance, electrical conductivity, and non-magnetic properties.

Surface Finishes

The surface treatment applied to cylinder nuts enhances their appearance, corrosion resistance, and sometimes lubricity.

• Zinc Plating: The most common finish for carbon steel nuts. It provides a shiny, silver appearance and good corrosion resistance. It often comes with a clear (blue) or yellow chromate conversion coating.

• Hot-Dip Galvanizing: A thick zinc coating applied for exceptional corrosion protection in outdoor or harsh industrial environments.

• Black Oxide: Provides a mild corrosion resistance and a clean, black finish. It is popular for its aesthetic appeal and reduces light glare.

• Nickel Plating: Offers a hard, shiny, and corrosion-resistant surface, often used in decorative applications or for specific chemical resistance.

• Cadmium Plating: (Now less common due to toxicity) Provides excellent corrosion resistance and lubricity, historically used in aerospace.

• Phosphate Coating: Often used as a base for holding oil or paint, or for its anti-galling properties.

Specifications

Cylinder nuts are specified by several key dimensions and features:

• Thread Size: The internal thread pitch and size (e.g., M6x1.0, 1/4″-20).

• Cylinder Diameter (O.D.): The outer diameter of the barrel.

• Cylinder Length / Height: The overall length of the nut.

• Keyway Dimensions: The width and depth of the slot machined into the side of the cylinder for an anti-rotation pin or setscrew.

• Material Grade: Denotes the strength class (e.g., Grade 8, Class 10.9 for high-strength steel).

Application Fields

Cylinder nuts are essential in applications where a strong, reliable, and clean fastener is needed without external wrenching features.

• Aerospace: Extensively used in airframe construction to join sections of aluminum skin to the underlying structure.

• Automotive: Used in chassis assembly, engine components, and high-performance vehicles where space is constrained.

• Machinery and Automation: Ideal for securing panels, guards, and components on machinery where a smooth exterior is desired.

• Electronics: Used to assemble robust electronic enclosures and racks.

• Furniture Manufacturing: Common in high-end, modern, or commercial furniture for creating invisible, strong joints.

An Excellent Use Case: Assembly of an Aircraft Wing Skin

The Challenge: An aerospace manufacturer needs to attach the large, curved aluminum skin panels of an aircraft wing to the underlying ribs and spars. The fastening must be incredibly strong to handle immense aerodynamic and structural loads. The exterior surface of the wing must be perfectly smooth to maintain aerodynamic efficiency. There is no access to the inside of the wing structure once the skin is in place.

Why Cylinder Nuts are the Perfect Solution:

1. Blind Installation: Cylinder nuts are inserted into precisely machined pockets in the wing’s internal ribs and spars.

2. Anti-Rotation: A setscrew is driven through the rib into the nut’s keyway, locking it firmly in place and preventing any rotation.

3. Smooth Exterior: A bolt is then driven through the wing skin and into the fixed cylinder nut from the outside. The fastener head can be a flush countersunk head, creating the required perfectly smooth aerodynamic surface.

4. High Strength: Made from high-grade alloy steel or titanium and heat-treated, these nuts provide the exceptional strength and reliability required for flight-critical structures.

The Result: The aircraft wing is assembled with a multitude of incredibly strong, reliable fastenings that are completely invisible from the outside, ensuring optimal aerodynamic performance and structural integrity. This application is a classic and critical use of the cylinder nut.