Screw shopping mall---one-stop service
Language
Screw shopping mall---one-stop service
DIN 933 vs ISO 4017: What’s the Difference?
When sourcing hex head bolts for industrial, mechanical, or construction applications, buyers often come across two common standards: DIN 933 and ISO 4017. At first glance, these two standards look very similar, and in many cases, they are used interchangeably in the fastener market. However, there are still important points buyers should understand before placing an order.
So, DIN 933 vs ISO 4017: what’s the difference? In simple terms, both standards refer to hexagon head bolts with full thread, but they come from different standard systems and may have slight differences in dimensions, tolerances, and international usage. Understanding these differences helps buyers choose the right fastener specification and avoid confusion in procurement, engineering, and replacement applications.
What Is DIN 933?
DIN 933 is a German industrial standard for hexagon head bolts with full thread. For many years, DIN standards were widely used in Europe and became common references in the global fastener industry.
DIN 933 bolts are typically used in:
Machinery manufacturing
Equipment assembly
Construction applications
Automotive components
General industrial fastening
Because DIN standards were adopted early in many markets, DIN 933 remains a very familiar specification for manufacturers, distributors, and buyers.
What Is ISO 4017?
ISO 4017 is the international standard for hexagon head screws with full thread. It was developed under the International Organization for Standardization to create more globally unified specifications for fasteners.
ISO 4017 is commonly used in:
International engineering projects
Export-oriented manufacturing
Industrial equipment
Construction and infrastructure
Standardized global supply chains
Today, many manufacturers and buyers prefer ISO standards because they are more internationally recognized and aligned across different markets.
DIN 933 vs ISO 4017: Main Similarities
The reason these two standards are often confused is that they are very close in design and function.
Both DIN 933 and ISO 4017 describe:
Hexagon head fasteners
Fully threaded body
Metric dimensions
General-purpose industrial use
Compatibility with matching nuts and washers
In many practical applications, a DIN 933 bolt and an ISO 4017 bolt of the same size may appear almost identical.
DIN 933 vs ISO 4017: Main Differences
Although the two standards are very similar, they are not always exactly the same.
1. Standard System
The most obvious difference is the origin of the standard.
DIN 933 belongs to the German DIN system
ISO 4017 belongs to the international ISO system
This matters because some customers, drawings, and markets still specify one standard over the other.
2. Dimensional Details
In many sizes, DIN 933 and ISO 4017 are nearly equivalent, but certain dimensions or tolerance details may differ depending on the diameter and length range. These differences are usually small, but they can still matter in precision assemblies or strict engineering specifications.
3. Naming Convention
Another difference is terminology. DIN 933 is often referred to as a hex bolt, while ISO 4017 may be described as a hex head screw with full thread. In actual trade practice, however, both are often treated as the same type of product.
4. Market Preference
Some customers still prefer DIN references because of long-term industry habits, while others request ISO standards for global project consistency. For export business, ISO 4017 may be more commonly requested in technical documents and international procurement.
Which One Should Buyers Choose?
For most general industrial applications, the choice between DIN 933 and ISO 4017 depends on the customer’s drawing, project standard, and market requirements.
Buyers should pay attention to:
Whether the drawing specifically calls for DIN or ISO
Dimensional tolerances required by the project
Material grade and mechanical properties
Surface treatment requirements
Compatibility with existing components
If the project has strict engineering standards, it is always best to confirm the exact specification with the supplier before production or shipment.
Why This Difference Matters in Procurement
In fastener sourcing, small specification differences can lead to fitting problems, installation delays, or confusion during inspection. Even when two standards are very similar, buyers should not assume they are always fully interchangeable without verification.
Understanding DIN 933 vs ISO 4017 helps distributors, contractors, and OEM buyers communicate more clearly with manufacturers, especially in custom production or export orders.
So, DIN 933 vs ISO 4017: what’s the difference? Both standards refer to full-thread hex head fasteners and are very similar in structure and use, but they come from different standard systems and may have slight differences in dimensional details and market application.
For buyers, the safest approach is to follow the project drawing, confirm the required standard, and work with an experienced fastener supplier who understands both DIN and ISO specifications. This helps ensure the right fit, the right performance, and smoother procurement for industrial and construction projects.
Wuxi Zhuocheng Mechanical Components Co., Ltd. is established in 1990, and one group of manufacturing and selling professional fastener
Copyright © 2026 Wuxi Zhuocheng Mechanical Components Co.,Ltd. - All Rights Reserved.
