ASME B18.2.2: Understanding Nuts for General Applications

ASME B18.2.2 is latest version of ANSI B18.2.2M – 1981 Metric Plain Washers. ANSI B18.22M no more update exists.

In the world of fasteners, nuts play a crucial role in securing various components in place, ensuring structural integrity and reliability. The American Society of Mechanical Engineers (ASME) has established the B18.2.2 standard document, which delves into the specifications and dimensions of nuts for general applications, specifically focusing on machine screw nuts, hex nuts, square nuts, hex flange nuts, and coupling nuts within the inch series.

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ASME B18.2.2 Dimensions Discussed.

Let’s explore the dimensions outlined in this standard for different types of nuts:

1. Machine Screw Nuts:

Machine screw nuts are indispensable in fastening machine screws securely. ASME B18.2.2 delineates the dimensions of square and hex machine screw nuts, providing precise measurements to ensure compatibility and functionality with corresponding machine screws.

Table 1-1 Dimensions of Square and Hex Machine Screw Nuts as per ASME B18.2.2

2. Small Pattern Hex Machine Screw Nuts:

In instances where space is limited, small pattern hex machine screw nuts come to the rescue. ASME B18.2.2 specifies their dimensions, allowing for seamless integration into compact assemblies while maintaining robust fastening capabilities.

Table 1-2 Dimensions of Small Pattern Hex Machine Screw Nuts as per ASME B18.2.2

3. Square Nuts:

Square nuts offer enhanced grip and resistance to loosening compared to their hexagonal counterparts. The standard meticulously outlines the dimensions of square nuts, facilitating their effective utilization across a spectrum of applications.

Table 2 Dimensions of Square Nuts as per ASME B18.2.2

4. Hex Flat Nuts and Hex Flat Jam Nuts:

Hex flat nuts and hex flat jam nuts provide a reliable means of fastening components with flat surfaces. ASME B18.2.2 provides detailed dimensions for these nuts, ensuring optimal engagement and torque distribution.

Table 3 Dimensions of Hex Flat Nuts and Hex Flat Jam Nuts as per ASME B18.2.2

5. Hex Nuts and Hex Jam Nuts:

Among the most ubiquitous fasteners, hex nuts and hex jam nuts find widespread use in various industries. The standard specifies their dimensions, enabling seamless integration into assemblies and ensuring robust fastening performance.

Table 4 Dimensions of Hex Nuts and Hex Jam Nuts as per ASME B18.2.2

6. Hex Slotted Nuts:

Hex slotted nuts offer the added benefit of facilitating secure fastening with the use of a cotter pin or a lock washer. ASME B18.2.2 elucidates their dimensions, ensuring compatibility with locking mechanisms for enhanced safety and stability.

Table 5 Dimensions of Hex Slotted Nuts as per ASME B18.2.2

7. Hex Thick Nuts:

Hex thick nuts are designed to withstand higher loads and provide increased bearing surface area. ASME B18.2.2 delineates their dimensions, ensuring proper fit and functionality in heavy-duty applications.

Table 7 Dimensions of Hex Thick Slotted Nuts as per ASME B18.2.2

8. Heavy Square Nuts:

Heavy square nuts are engineered to withstand elevated loads and offer enhanced durability. The standard provides precise dimensions for these nuts, ensuring compatibility with heavy-duty fastening requirements.

Table 8 Dimensions of Heavy Square Nuts as per ASME B18.2.2

9. Heavy Hex Nuts and Heavy Hex Jam Nuts:

Heavy hex nuts and heavy hex jam nuts are designed to provide superior strength and reliability in demanding applications. ASME B18.2.2 specifies their dimensions, ensuring robust fastening performance in heavy-duty environments.

Table 9 Dimensions of Heavy Hex Flat Nuts and Heavy Hex Flat Jam Nuts as per ASME B18.2.2

10. Hex Flange Nuts and Large Hex Flange Nuts:

Hex flange nuts and large hex flange nuts feature an integrated flange that distributes load and prevents loosening. The standard outlines their dimensions, ensuring proper fit and functionality in applications requiring enhanced resistance to vibration and torque.

Table 10 Dimensions of Heavy Hex Nuts and Heavy Hex Jam Nuts as per ASME B18.2.2

11. Hex Coupling Nuts:

Hex coupling nuts are employed to connect two threaded rods or studs together. ASME B18.2.2 provides precise dimensions for these nuts, ensuring compatibility and secure fastening of threaded components.

Table 11 Dimensions of Heavy Hex Slotted Nuts as per ASME B18.2.2

Dimensions of Hex Flange Nuts and Large Hex Flange Nuts.

Dimensions of Hex Coupling Nuts.

In conclusion, ASME B18.2.2 serves as a comprehensive guide for the dimensions of nuts for general applications, offering invaluable insights into the specifications required for seamless integration and reliable performance across diverse industries and applications. By adhering to the dimensions outlined in this standard, engineers and manufacturers can ensure the compatibility, functionality, and integrity of nut-fastened assemblies, contributing to enhanced safety and efficiency in myriad engineering endeavors.