MPN

Shoulder Bolts

A shoulder bolt, also known as a shoulder screw, is a specialised fastener distinguished by an unthreaded cylindrical section between the head and the threads.

This unique design allows the bolt to act as a pivot point, shaft, or dowel, making it indispensable for mechanical assemblies requiring precision movement.

At RS Australia, we offer a comprehensive selection of high-quality shoulder bolts, ranging from robust stainless steel options to various metric and imperial sizes.

Whether for automotive engineering or precision machinery, our range ensures you have the reliable fastening solutions necessary for professional results.

Key Benefits of Shoulder Bolts

Utilising a shoulder screw offers significant mechanical advantages, providing a precise bearing surface that standard fasteners simply cannot replicate for moving parts.

High Load Withstanding: These robust fasteners support substantial shear forces, making them ideal for securing heavy industrial machinery and moving assemblies.
Easy Installation: You can achieve secure fittings using standard wrenches or hex keys, eliminating the need for complex specialised equipment.
Strength Against Movement: By providing a rigid pivot point, they prevent unwanted lateral shifting between connected materials in large-scale structures.
Facilitates Maintenance: The unique design allows for the quick disassembly of rotating parts, significantly streamlining routine mechanical repair work.
Cost-Effective: Compared to custom-machined shafts, shoulder bolts offer a highly affordable and high-performance fastening solution.

Types of Shoulder Bolts

Shoulder bolts are available in various dimensions, materials, and physical designs to meet different application requirements.

By Size System

Shoulder bolts come in two measurement standards, enabling user to ensure global equipment compatibility:

Metric Shoulder Bolts: These high-strength shoulder bolts come in sizes like M5, M6, and M8 (measured in mm), providing various holding powers. For instance, the M6 shoulder bolt has a 6mm diameter shaft. Metric shoulder bolts have a full thread length, allowing higher torque to be applied during installation.
Imperial Shoulder Bolts: Widely utilised in legacy equipment and North American automotive sectors, imperial shoulder bolts offer easy installation for systems using inch-based sizing.

By Material

The shoulder bolt’s material dictates its longevity and resistance to atmospheric degradation. Common options include:

Stainless Steel: Highly durable stainless steel shoulder bolts provide superior corrosion resistance, making them the standard choice for food-grade and marine environments.
Brass: These fasteners offer excellent conductivity and low friction, frequently used in electrical applications or where decorative, non-sparking properties are required.
Aluminium: Lightweight yet robust, these screws are perfect for aerospace and weight-sensitive electronic assemblies where high-speed movement is a primary factor.

By Design

Head geometry determines how a fastener integrates into a machine's spatial constraints:

Standard: Featuring a traditional hexagonal or socket head at one end, these shoulder screws provide a secure gripping surface for standard tools during high-torque installations.
Headless: A headless shoulder bolt is engineered with a flat end for confined spaces, sitting flush or recessed to prevent interference with other moving parts.

How to Choose the Right Shoulder Bolt for Your Needs

Selecting the ideal shoulder screw is critical for mechanical precision, as the unthreaded section must perfectly match your pivot or spacer requirements. Consider the following factors:

Load Requirements: Ensure the fastener can withstand the shear forces of your application. For instance, stainless steel shoulder bolts offer superior strength for heavy industrial pulleys.
Size: Precise measurements of the shoulder diameter and length are vital to ensure compatibility. For example, choose an M5 shoulder bolt for a snug fit in 5mm bores.
Thread Specifications: Match the thread pitch for secure fastening by verifying if your application requires metric or imperial threading.
Environment: Evaluate the atmospheric conditions of your application when choosing a material. For instance, stainless shoulder bolts are necessary for preventing rust in high-moisture or chemical-heavy processing areas.
Space Constraints: In compact assemblies, a headless shoulder bolt is often the best solution to avoid interference with other moving mechanical parts.

Common Industry Applications of Shoulder Bolts

High-performance shoulder bolts are critical components across various Australian sectors, serving as precision axles or mounting points for mechanical movement.

Automotives and Transportation: Engine assemblies utilise these fasteners as pivots for pulleys and belt tensioners, ensuring smooth rotation and accurate alignment within vehicle drive systems.
Machinery: Industrial gearboxes incorporate shoulder screws to act as stationary shafts for rotating gears, providing low-friction surfaces for heavy-duty operation.
Manufacturing and Assembly: Production lines rely on shoulder bolts to secure precision jigs and fixtures, allowing parts to slide or rotate during fabrication.
Aerospace and Defence: Engineers use stainless steel shoulder bolts for landing gear components and control surfaces where high shear strength and corrosion resistance are mandatory.
Construction: In large-scale infrastructure, these bolts function as essential hinge pins for heavy access doors and pivoting security gates across commercial sites.
Electronics and Instrumentation: Compact shoulder bolts are used to mount delicate circuit boards or moving optical lenses, ensuring precise spacing without overtightening components.

Buy Shoulder Bolts at RS Australia

As a premier supplier and distributor of professional fasteners and fixings, RS Australia stocks a comprehensive range of high-precision shoulder bolts in Australia. Our inventory features items sourced from reputable brands like Phoenix Contact and RS PRO, ensuring every product meets the strictest quality benchmarks.

We also provide components like electrical socket screws, machine bolts, and hex bolts to support other parts of your project lifecycle.

Browse our online store to explore the full collection and have your items delivered directly to your facility in Australia. With our flexible and swift delivery options, we ensure your commercial operations remain on schedule with reliable availability.

For more details regarding shipping times and fees, please visit our delivery information page.