ISO Standards for Fasteners | Differences Between ANSI and ISO Standards


ISO standard is an important guideline to follow in manufacturing and quality control, what ISO standards are applied to fasteners and what are they used for? We’ll also talk about the differences between ISO and ANSI standards here.

What Are ISO Standards for Fasteners and Common Types?

ISO (International Standards Organization) has developed several standards related to fasteners. These standards provide guidelines and specifications for various types of fasteners, ensuring consistency, interoperability, and quality. ISO standards cover a range of fastener types, including bolts, screws, studs, nuts, and washers. They address aspects such as dimensions, tolerances, mechanical properties, and other technical requirements.

1. ISO 898: a most commonly used metric specification specifies mechanical and physical properties of bolts, screws, and studs made of carbon steel or alloy steel. It covers different grades and tensile strength classes for fasteners.

2. ISO 4014 and ISO 4017: These standards specify dimensions, tolerances, and technical requirements for hexagon head bolts (partial thread and full thread, respectively). They provide information on thread sizes, lengths, head dimensions, and other characteristics.

3. ISO 4762: This standard specifies dimensions, tolerances, and technical requirements for hexagon socket head cap screws. It covers various sizes, lengths, head dimensions, and other details.

4. ISO 10642: This standard specifies dimensions, tolerances, and technical requirements for countersunk head screws (flat and oval head) with hexagon socket.

5. ISO 4032: This standard specifies dimensions, tolerances, and technical requirements for hexagon nuts. It includes information on thread sizes, widths across flats, heights, and other specifications.

6. ISO 7040: This standard specifies prevailing torque-type steel nuts with non-metallic inserts.

7. ISO 7089: This standard specifies plain washers.


There are also ISO 9001:2015 and ISO 17025:2017 standards that are not specific to fasteners but widely used. 

More Types of Fastener Standards

– DIN Standards: Developed by Deutsches Institut für Normung (DIN), these standards are widely used in Germany and have gained international acceptance. Examples include DIN 931/933 for hexagon head bolts, DIN 125 for flat washers, and DIN 934 for hexagon nuts.

– ASME Standards: Developed by the American Society of Mechanical Engineers (ASME), these standards are widely used in the United States and are often referenced globally. Examples include ASME B18.2.1 for square head bolts, ASME B18.21.1 for flat washers, and ASME B18.2.2 for hexagon nuts.

– ASTM Standards: Developed by ASTM International, these standards cover a wide range of industries and materials, including fasteners. Examples include ASTM F3125 for structural bolts, ASTM F436 for hardened steel washers, and ASTM A194 for nuts for high-pressure and high-temperature service.

– JIS Standards: Developed by the Japanese Industrial Standards (JIS), these standards are widely used in Japan and have influenced standards globally. Examples include JIS B1180 for hexagon head bolts, JIS B1163 for flat washers, and JIS B1181 for hexagon nuts.

– BS Standards: Developed by the British Standards Institution (BSI), these standards are used in the United Kingdom and have historically influenced global standards. Examples include BS 3692 for ISO metric precision hexagon bolts, BS 4320 for plain washers, and BS 3692 for hexagon nuts.

Differences Between ANSI and ISO Standards

ANSI (American National Standards Institute) and ISO (International Organization for Standardization) are two different organizations that develop standards, and there are some notable differences between them. 

1. Scope: ANSI standards primarily focus on standards developed within the United States, while ISO standards have global reach and are developed and adopted internationally.

2. Governance: ANSI is a private, non-profit organization that coordinates and accredits various standards development organizations within the United States. ISO is an international standardization body with member organizations from different countries.

3. Development Process: ANSI standards are typically developed through a consensus-based approach, involving stakeholders from relevant industries, government agencies, and consumer groups. ISO standards also follow a consensus-based approach but involve experts and representatives from different countries.

4. Global Adoption: ISO standards have broader international recognition and adoption compared to ANSI standards, which are primarily applicable within the United States. ISO standards are often referenced and accepted globally in various industries.

5. Numbering and Nomenclature: ANSI standards typically have an alphanumeric nomenclature, such as ANSI/ASME B18.2.1 for square head bolts. ISO standards follow a numeric-based system, such as ISO 898-1 for mechanical properties of fasteners.

6. Regional Preferences: ANSI standards are more commonly adopted in the United States and tend to align with American preferences and practices. ISO standards are used globally and aim for broader international alignment.