Global Fastener Standards Explained: Why Are There So Many? Differences, Uses, and How to Choose
- 翰君 陳
- 2 days ago
- 4 min read
When searching for screws, nuts, washers, retaining rings, or dowel pins, you may encounter a long list of standards: DIN, ISO, JIS, ANSI, ASTM, CNS, GB, BS, AS…Why are there so many? What’s the difference? How do you choose the correct one?
This article breaks down the origins, differences, and real-world uses of global fastener standards in a clear and easy-to-understand way.
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1. Why Do We Need Fastener Standards?
Fasteners are mating parts—screws match nuts, washers match hole sizes.Even the slightest difference in thread pitch or dimensions can cause:
Screws that won’t go in
Stripped threads
Jamming
Non-interchangeable or unrepairable parts
Equipment damage
Standards exist to ensure that fasteners are interchangeable, repairable, compatible, and suitable for mass production.
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2. Why Do So Many Standards Exist?
During early industrial development, each country established its own standards based on local industry, manufacturing habits, and engineering practices.
As a result, European, American, Japanese, Taiwanese, and other systems evolved independently.
Behind every standard is a unique industrial history, which is why the same screw may have different names, dimensions, or tolerances depending on the country.
Although ISO later attempted to unify global standards, countries continue using their existing systems, resulting in the multi-standard environment we have today.
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3. Overview of Major Global Fastener Standards
Below is a summary of global fastener standards grouped into five major regions.
(1) International Standards
ISO (International Organization for Standardization)
The most widely adopted industrial standard worldwide.Used heavily in cross-border equipment.Its purpose is to unify specifications between countries, making replacement and purchasing easier.Many nations gradually adopt ISO to replace local standards.
(2) European Standards
DIN (Germany)
The most common standard in Taiwan.Covers most screws and washers.Known for precision, completeness, and used in machine tools and automation equipment.Many countries modeled their own standards after DIN.
EN (European Union)
Unified EU standard, highly compatible with DIN and ISO.Used in European-made machinery.Many DIN standards have transitioned to EN.
UNI (Italy)
Common in Italian food processing and packaging machinery.Compatible with ISO but retains Italian industrial characteristics.
NF (France)
Widely used in French-made equipment.Partially integrated with EN/ISO.Still appears in European maintenance scenarios.
BS (British Standard)
One of the earliest industrial standards.Modern rules often originate from BS.Although much has shifted to EN/ISO, older British equipment continues to use BS.
(3) U.S. Standards
ANSI (American National Standards Institute)
The primary American standard, mainly using inch-based sizes.Common in U.S. machinery, construction, and manufacturing.
ASME (American Society of Mechanical Engineers)
Focuses on machinery, geometry, pressure vessels, and piping.Often used together with ANSI.
ASTM (American Society for Testing and Materials)
Defines material properties such as strength, corrosion resistance, and heat treatment.High-strength bolts and steel materials rely heavily on ASTM.
SAE (Society of Automotive Engineers)
Defines automotive bolt grades (ex: Grade 5, Grade 8).Used for high-impact and vibration-resistant fastening.
IFI (Industrial Fasteners Institute)
Fastener-specific standards for screw heads, nut sizes, and washer dimensions.The core reference for American fastener specifications.
(4) Asian Standards
JIS (Japanese Industrial Standards)
The dominant precision fastener standard in Asia.Widely used in 3C electronics, machine tools, and semiconductor equipment.
CNS (Taiwan)
Aligned with JIS/ISO but adjusted for Taiwanese industrial practices.
KS (Korea)
Derived from JIS with high compatibility.Common in Korean-made machinery and appliances.
IS (India)
Partially ISO-compatible while retaining characteristics of Indian industry.
(5) Other Important Standards
GB (China)
China’s main standard, similar but not identical to DIN/ISO.
GOST (Russia)
Used in Russia and parts of Eastern Europe.Different appearance and tolerances; low interchangeability.
AS (Australia)
Similar to BS/ISO.Common in construction and steel structures.
Standard | Country / Region | Characteristics | Common Applications |
ISO | International | Most widely used globally | Factories, automation equipment |
DIN | Germany | Most common in Taiwan; high precision | Machine tools, automation |
EN | European Union | Similar to DIN / ISO | European equipment |
UNI | Italy | Common in food processing & packaging lines | European production lines |
NF | France | Integrated with EN / ISO | French equipment |
BS | United Kingdom | One of the earliest industrial standards | UK-made equipment |
AS | Australia | Similar to BS / ISO | Construction, machinery |
ANSI | United States | Mainstream U.S. standard (inch-based) | Factories, construction |
ASME | United States | Standards for piping & mechanical geometry | Industrial machinery |
ASTM | United States | Material & strength standards | Steel structures, bolts |
SAE | United States | Automotive bolt grades | Automotive industry |
IFI | United States | Fastener-specific standards | Screws, nuts |
JIS | Japan | Main standard for precision equipment in Asia | 3C electronics, machine tools |
CNS | Taiwan | Aligned with JIS / ISO | Local machinery |
KS | Korea | JIS-based | Machine tools, appliances |
IS | India | Partially ISO-compatible | Indian equipment |
GB | China | Common in Chinese-made export equipment | Chinese machinery |
GOST | Russia | Low interchangeability | Russian equipment |
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4. What Makes These Standards Different?
Fastener standards are not interchangeable because they differ in key aspects:
Metric vs. Inch unitsM6 ≠ 1/4". The difference is enough to cause failure.
Thread pitch differencesMetric = pitch (mm)UNC/UNF = TPINot compatible.
Strength grading systems differ8.8 / 10.9 / 12.9 vs. Grade 5 / Grade 8.
Head dimensions differExample: DIN 912 vs. ISO 4762 have different head heights.
Tolerance differencesEven with the same nominal size, allowable deviations differ.
A 0.1 mm mismatch can cause stripping, jamming, or serious damage.
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5. Which Industries Use Each Standard?
Standard | Common Industries |
ISO | Global equipment, automation |
DIN | Machine tools, automation |
JIS | Electronics, precision machinery |
ANSI / ASME | U.S.-made machinery, construction |
ASTM | Steel structures, high-strength bolts |
SAE | Automotive |
CNS | Taiwanese equipment |
GB | Chinese machinery |
GOST | Russian machinery |
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6. How to Quickly Identify the Correct Standard
Determine metric or inch (mm / inch)
Identify the country of origin of the equipment
Check head markings or standard codes (ex: DIN 912)
Keep screws, nuts, washers within the same standard
When unsure: take photos + measure dimensions and ask your supplier
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7. Why Choose Sheng Fong Precision?
Sheng Fong Precision specializes in mixed Metric / Inch / International fastener standards.We help customers quickly identify correct specifications, preventing mismatches and delays.
We provide:
Standard identification support
Head shape, pitch, dimension, and tolerance comparison
Full Metric + Inch inventory
MISUMI / McMaster-Carr compatible alternatives
Local stock with fast delivery
📩 Need help identifying standards or finding alternative specifications? Contact us on LINE: @s9000
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