At HETAI, custom fasteners are manufactured and inspected according to customer drawings, technical specifications, and applicable international standards. Unlike standard fasteners, which usually follow established specifications, custom fasteners may have unique dimensions, thread designs, materials, mechanical properties, and surface treatments. Therefore, the applicable quality standards depend on the product design and its intended application.

Several international standards are commonly used as references when manufacturing and inspecting custom fasteners.

1. ISO Standards

ISO standards are widely used in the global fastener industry. They cover fastener dimensions, mechanical properties, materials, testing methods, and other technical requirements.

Common examples include:

• ISO 898-1: Mechanical properties of fasteners made of carbon steel and alloy steel, including bolts, screws, and studs.
• ISO 3506: Mechanical properties of corrosion-resistant stainless steel fasteners.
• ISO 4014: Hexagon head bolts with partial thread.
• ISO 4017: Hexagon head bolts with full thread.
• ISO 4032: Hexagon regular nuts.
• ISO 965: Tolerances for ISO metric screw threads.

For custom fasteners, these standards can provide useful technical references even when the product has a non-standard design.

2. DIN, ANSI, ASTM, and JIS Standards

Depending on the customer’s market and application, other international or national standards may also apply.

• DIN: German industrial standards commonly referenced in mechanical engineering and fastener manufacturing.
• ANSI: American National Standards Institute standards used in various industrial applications.
• ASTM: Standards covering materials, mechanical properties, and testing requirements for many types of fasteners.
• JIS: Japanese Industrial Standards used in Japanese and international manufacturing industries.

Customers may specify one of these standards in their technical drawings or purchasing documents. HETAI can review the requirements and determine the appropriate manufacturing and inspection criteria.

3. Material and Mechanical Property Standards

Material quality and mechanical performance are particularly important for fasteners used in load-bearing or safety-critical applications.

Depending on the product, relevant requirements may cover:

• Chemical composition of the material
• Tensile strength and yield strength
• Hardness
• Proof load
• Heat treatment requirements
• Corrosion resistance

For example, ISO 898-1 is commonly used for the mechanical properties of carbon steel and alloy steel fasteners, while ISO 3506 applies to corrosion-resistant stainless steel fasteners.

When customers require high-strength fasteners such as property classes 8.8, 10.9, or 12.9, the material, manufacturing process, heat treatment, and testing methods must be selected to meet the applicable requirements.

4. Dimensional and Thread Standards

Custom fasteners may have special dimensions or thread configurations. However, standard measurement principles and thread specifications can still be applied where appropriate.

Common requirements include:

• Overall dimensions and geometric tolerances
• Metric or inch thread specifications
• Thread pitch and tolerance class
• Thread engagement and fit
• Head dimensions and other critical features

For non-standard threads or special geometries, the customer should provide detailed drawings and clearly define the required tolerances and acceptance criteria.

5. Surface Treatment and Corrosion Testing Standards

Surface treatments can affect corrosion resistance, appearance, and service life. Depending on the material and finish, relevant standards may cover coating thickness, surface quality, and corrosion testing.

For example, ISO 4042 addresses electroplated coating systems for fasteners, while ISO 9227 specifies salt spray testing procedures used to evaluate corrosion resistance.

The required coating type, thickness, corrosion test duration, and acceptance criteria should be agreed upon before production.

6. Customer Drawings and Inspection Requirements

Not every custom fastener must comply with every standard listed above. The applicable requirements depend on the product’s design, industry, operating environment, and customer specifications.

At HETAI, we review the following information before production:

• 2D engineering drawings or 3D CAD models
• Material specifications
• Dimensional tolerances
• Thread standards and requirements
• Mechanical property requirements
• Surface treatment specifications
• Inspection methods and acceptance criteria

When a product combines standard and customized features, we can use relevant international standards for the applicable dimensions or performance requirements while following the customer’s drawings for the custom features.

How Does HETAI Ensure Compliance with Quality Standards?

As a custom fasteners manufacturer with over twenty years of experience, HETAI understand that different customers and industries have different quality requirements. Our team evaluates the technical specifications before production and selects suitable materials, manufacturing processes, and inspection methods accordingly.

We can support custom fastener projects based on applicable ISO, DIN, ANSI, ASTM, and JIS standards, as well as customer-specific technical requirements.

Since 2001, HETAI has focused on manufacturing custom fasteners and precision hardware components. By combining manufacturing experience with appropriate quality standards and inspection procedures, we help customers obtain products that meet their dimensional, mechanical, and application requirements.