Comparison Table of Fastener Standards: Chinese National Standards, German Standards, and International Standards

Introduction: Why Standard Interchangeability Matters

In the global supply chain, precision is everything. A single millimeter's difference can compromise the mechanical integrity of an entire assembly. At Ever Power, we frequently encounter projects where a European design specifies DIN, while local production requires GB (Chinese Standard) or the universal ISO. Understanding these cross-references is not just a logistical necessity—it is a cornerstone of professional engineering and quality assurance.

This guide provides a comprehensive narrative breakdown of standard fastener types and their equivalent designations across major global standards.

1. High-Strength Bolts and Socket Cap Screws

Bolts and screws form the backbone of structural engineering. The transition from DIN to ISO standards often involves subtle changes in head height or width across flats, making standard awareness critical.

Hexagon Socket Head Cap Screws (Socket Caps)

Commonly used in machinery and mold making, the DIN 912 is the world's most recognized socket cap screw. Its Chinese counterpart is GB 70-85, and it aligns globally with ISO 4762. These fasteners are prized for their high tensile strength and space-saving head design.

Standard Hexagon Bolts (Full and Partial Thread)

Hex bolts are the industry workhorses. For partial thread (shanked) bolts, use DIN 931, which corresponds to GB 5782-86 and ISO 4014. For full thread bolts, DIN 933 is the standard, aligning with GB 5783-86 and ISO 4017. At Ever Power, we emphasize that while these are largely interchangeable, ISO standards sometimes specify different head dimensions for sizes like M10, M12, and M14.

Hexagon Socket Set Screws

Used to secure pulleys or gears to shafts, these headless screws come in various point types:

• Flat Point: DIN 913 | GB 77-85 | ISO 4026.
• Cone Point: DIN 914 | GB 78-85 | ISO 4027.
• Dog Point: DIN 915 | GB 79-85 | ISO 4028.
• Cup Point: DIN 916 | GB 80-85 | ISO 4029.

2. Nut Standards and Locking Mechanisms

Nuts must perfectly match the thread tolerance and material grade of their corresponding bolts. Choosing the wrong standard can lead to “thread galling,” a common issue particularly in stainless steel fasteners.

Hexagon Full Nuts (Type 1)

The standard hex nut is defined by DIN 934. In the Chinese market, this is GB 6170-86, while the international standard is ISO 4032. For Fine Pitch applications, DIN 934 still applies, but it corresponds to GB 6171-86 and ISO 8673.

Nylon Insert Lock Nuts

To prevent loosening under vibration, nylon lock nuts are essential. The standard heavy type is DIN 982 (GB 812-88 / ISO 2982), whereas the more common thin/regular type is DIN 985 (GB 889.1-86 / ISO 7040). For aesthetic or enclosed applications, Domed Cap Lock Nuts follow DIN 986 (GB 6172.2-86 / ISO 10511).

Thin and Jam Nuts

Used where space is restricted or as a second “jam nut” to lock a primary nut, DIN 439 and DIN 936 are the go-to standards, corresponding to GB 6172-86 and ISO 4035.

3. Plain and Spring Washers

Washers distribute load and prevent surface damage. Even here, standard variations exist in chamfering and thickness.

Plain (Flat) Washers

The standard Type A plain washer is DIN 125-A (GB 97.1-85 / ISO 7089). If a chamfered edge is required for high-grade assemblies, specify DIN 125-B (GB 97.2-85 / ISO 7090). For rougher construction where a larger clearance is needed, DIN 126 (ISO 7091) is the alternative.

Spring Lock Washers

To provide tension, Standard Spring Washers follow DIN 127-B (GB 93-87), while the Heavy Duty Tang End version is DIN 127-A (GB 7244). For specialized vibration resistance, Ever Power also provides Wave Washers (DIN 137-B / GB 955) and Curved Washers (DIN 137-A).

4. Tapping, Self-Drilling, and Wood Screws

These fasteners are defined by their drive type (slotted vs. cross-recessed) and head style.

• Self-Drilling Tapping Screws: Known as DIN 7504, these correspond to the GB 15856.1-4 series. They eliminate the need for pre-drilling in metal sheets.
• Cross Recessed Pan Head Tapping Screws: DIN 7981, equivalent to GB 845-85 and ISO 7049.
• Cross Recessed Countersunk (Flat Head) Tapping Screws: DIN 7982, equivalent to GB 846-85 and ISO 7050.
• Hex Head Wood Screws: Often used in heavy timber construction, these follow DIN 571 (GB 102-86).

5. Industrial Specialty Standards

For niche industrial applications, the following cross-references are vital:

• Lifting Eye Bolts: DIN 580 | GB 825-76 | ISO 3266.
• Retaining Rings (Circlips): For shafts, use DIN 471 (GB 893-86). For bores, use DIN 472 (GB 893.86).
• Weld Nuts: Square weld nuts follow DIN 928 (GB/T 13680-92), while hexagonal weld nuts follow DIN 929 (GB/T 13681-92).
• Carriage Bolts: Mushroom head square neck bolts follow DIN 603 (GB 14-88 / ISO 8677).