Shoulder Screws

Hex Socket Shoulder Screws (Shoulder Bolts) – Precision Fasteners for Engineering and Mechanical Applications

At Newport Fasteners, we offer a wide range of Hex Socket Shoulder Screws, also known as Shoulder Bolts, Precision Shoulder Screws, or Stripper Bolts. These versatile and precision-engineered fasteners are designed for applications that require precise alignment, rotational movement, or spacing. With a unique design that combines functionality beyond standard bolts and screws, our Hex Socket Shoulder Screws provide superior performance in industries such as aerospace, automotive, machinery, and robotics.

The precision shoulder of these screws ensures tight tolerances, allowing for smoother operation in mechanical systems. Whether you're using them as a pivot point, shaft, spacer, or guide, Shoulder Bolts are ideal for reducing the need to modify standard fasteners to meet the demands of modern engineering.

What Are Hex Socket Shoulder Screws (Shoulder Bolts)?

Hex Socket Shoulder Screws are threaded fasteners that consist of three key components: the head, the smooth cylindrical shoulder (the non-threaded section), and the threaded portion. The smooth shoulder protrudes from the mating surface once installed, providing a reliable axis for components to rotate, pivot, or slide. The threaded portion secures the fastener in place, while the smooth shoulder provides a surface that components like gears, pulleys, or bearings can interact with.

These fasteners are particularly useful in applications where precision, durability, and versatility are critical. The unique design eliminates the need for custom machining, reducing time and cost while ensuring a high degree of functionality in modern mechanical systems.

Key Features of Shoulder Screws

Every Shoulder Bolt or Hex Socket Shoulder Screw consists of three essential elements:

1. Head

The head is typically a cap head or hex socket head, though variations like flat heads or low-profile heads are available depending on the application’s requirements. The hex socket drive enables secure tightening with a reduced risk of stripping or slippage, offering superior torque control.

2. Shoulder

The shoulder is the smooth, cylindrical portion of the bolt that extends from the threaded part. It is manufactured to tight tolerances and acts as the key feature that distinguishes Shoulder Screws from standard fasteners. The shoulder diameter and length are crucial to the screw’s function, as they define how the fastener interacts with other components.

3. Threaded End

The threaded portion attaches the screw to the mating surface. The length of the threaded section is typically shorter than traditional bolts, allowing the shoulder to remain exposed and function as a pivot or spacer.

Uses of Hex Socket Shoulder Screws (Shoulder Bolts)

Because of their precision design, Hex Socket Shoulder Screws are widely used in applications that demand accurate positioning, movement, and alignment. Some common uses include:

  • Pivot Point: The smooth shoulder acts as a rotating or pivot point for components like levers, gears, or pulleys.
  • Spacer: The shoulder provides a consistent gap between components, ensuring proper spacing and alignment.
  • Guide: Shoulder screws can act as guides for sliding components, allowing for controlled, smooth movement.
  • Bearing Surface: The smooth, precision-ground shoulder provides a reliable surface for components to move against, reducing wear and friction.

These features make Shoulder Bolts invaluable in industries where precision is critical, such as automotive systems, aerospace, and robotics.

How to Measure Hex Socket Shoulder Screws

When specifying or ordering Shoulder Screws, it’s important to understand the key measurements:

1. Shoulder Diameter and Shoulder Length

These two measurements are the primary factors that define the size of a shoulder screw. For example, a "3/8 x 1-inch shoulder screw" refers to a screw with a 3/8-inch shoulder diameter and a 1-inch shoulder length.

  • Shoulder Diameter: The diameter of the smooth, cylindrical portion.
  • Shoulder Length: The length of the shoulder, from the base of the head to the start of the threads.

2. Other Measurements

Additional measurements include:

  • Head Diameter (A): The overall diameter of the bolt head.
  • Head Height (B): The thickness of the bolt head.
  • Thread Length (C): The length of the threaded portion of the screw.
  • Thread Diameter (D): The outer diameter of the threaded portion.
  • Thread Size (E): Indicates the threading standard (UNC/UNF for inch threads or metric thread pitch).

Thread Standards and Sizes

Shoulder Screws are available in both inch and metric thread sizes:

  • Inch Threads: Typically available in UNC (coarse) or UNF (fine) threads, measured by the outside thread diameter and the TPI (threads per inch).
    • Example: 1/4-20 represents a 1/4-inch outside thread diameter with 20 threads per inch.
  • Metric Threads: Measured by the outside thread diameter in millimeters, followed by the thread pitch (the distance between thread crests in millimeters).
    • Example: M6 x 1.0 represents a 6mm outside thread diameter with a 1.0mm pitch.

Variations in Shoulder Screws

While the design of Shoulder Screws is consistent, several variations exist to meet specific application needs:

Head Type

  • Hex Socket Cap Head: The most common head type, offering durability and ease of installation with hex wrenches.
  • Flat Head: Used when a flush surface is required.
  • Low-Profile Head: Ideal for applications where height clearance is limited.

Drive Type

Most Shoulder Bolts feature a hex socket drive for secure installation, but other options include:

  • 6-Lobe Drive: Provides increased resistance to cam-out and stripping.
  • Slotted Drive: Common in some shoulder bolt applications for easier tool access.

Thread Features

Some Shoulder Screws may feature extended threads or oversized threads for applications requiring additional holding power.

Nylon Patch

A Nylon Patch may be added to the threaded section, providing self-locking capabilities and preventing loosening under vibration.

Materials and Finishes

At Newport Fasteners, our Hex Socket Shoulder Screws are available in a variety of materials to suit different environmental and operational conditions:

  • 300 Series Stainless Steel: Offers corrosion resistance and high durability, suitable for a wide range of applications.
  • 400 Series Stainless Steel: Known for hardness and corrosion resistance, often used in demanding environments.
  • Alloy Steel: Provides high strength and durability, making it ideal for high-torque applications.
  • Brass: Corrosion-resistant and machinable, making it useful for electrical or decorative applications.
  • Titanium: Lightweight and highly corrosion-resistant, offering an excellent strength-to-weight ratio for high-performance applications.

Finishes include:

  • Black Oxide: A corrosion-resistant coating that provides a sleek, matte appearance.
  • Passivated: A chemically induced finish for stainless steel that enhances corrosion resistance.
  • Plain: Standard finish for shoulder screws that do not require additional coatings.

Applications of Hex Socket Shoulder Screws (Shoulder Bolts)

Hex Socket Shoulder Screws are used in a wide range of industries, including:

  • Aerospace: Precision components where exact spacing and movement are critical.
  • Automotive: Pivots, spacers, and fasteners for engines and mechanical systems.
  • Industrial Machinery: Guides, shafts, and spacers in high-precision equipment.
  • Robotics: Pivot points and guides for moving components in automated systems.
  • Furniture: Decorative fasteners that provide both aesthetic appeal and functionality.

Order Your Hex Socket Shoulder Screws Today

When precision, strength, and versatility are essential, Hex Socket Shoulder Screws from Newport Fasteners are the ideal solution. We offer a wide selection of sizes, materials, and finishes to meet your exact application needs. Browse our extensive product range and place your order today for fast, reliable shipping. At Newport Fasteners, we’re committed to delivering high-quality fasteners and exceptional service for all your fastening requirements.