4mm shank x 8mm long A2 shoulder nuts

What are Shoulder Nuts?

Shoulder nuts. also known as barrel nuts, are a specialised fastener designed with a cylindrical, unthreaded shoulder with a tapped internal thread in the shoulder. This shoulder provides additional functionality, acting as a precise locating feature or a spacer in various mechanical applications. Shoulder nuts are commonly used when accurate alignment and smooth motion are critical, offering enhanced versatility compared to standard nuts.

What Applications Are They Used For?

Shoulder nuts are widely employed in engineering and manufacturing applications where alignment, spacing, or load distribution is essential. They are commonly found in the automotive, aerospace, and machinery industries. Typical uses include acting as spacers, locating components within assemblies, or ensuring smooth movement in pivoting mechanisms. Their design allows them to withstand both axial and radial loads, making them suitable for high-precision assemblies or moving parts.

Design Features

Shoulder nuts are manufactured from 303 stainless steel, which offers excellent corrosion resistance, durability, and strength, making them ideal for challenging environments.

One critical design characteristic is the concentricity tolerance of 0.05 mm between the thread and the shank diameter. This ensures precise alignment, reducing the risk of misalignment in sensitive applications. Additionally, shoulder nuts are produced with tight tolerances on dimensions such as shoulder diameter, shoulder length, and head diameter to guarantee compatibility and performance. These tolerances are meticulously controlled during manufacturing and are specified in the product line drawing. This product is also available in 316 stainless steel.