Differentiating Thread Types in Hydraulic Fitting Joints

Differentiating Thread Types in Hydraulic Fitting Joints

Differentiating Thread Types in Hydraulic Fitting Joints: Industrial Safety and Standardization Perspective

Abstract:
 Accurate classification of threaded fasteners used in hydraulic systems is critical to maintaining system integrity and ensuring operational safety. This study discusses the technical differences between metric and inch (imperial) threads, the practical challenges encountered and the marking requirements imposed under the DIN EN ISO 228-1 standard. Failures and risks caused by incorrect connections were analyzed and the applicability of standardization in the field was discussed.

1. Introduction

Hydraulic systems are precision engineered products that operate under high pressure. Improper selection of fasteners in these systems; It can cause leakage, connection failure or serious security vulnerabilities. One of the most common problems is the mixing of metric and inch-based screw threads.

2. Technical Differences of Thread Types

3. Challenges and Risks in the Field

In mechanical maintenance and assembly processes, especially in older systems, visual detection of the type of thread is almost impossible. In case of the wrong type of connection:

• gaps are formed on the joint surface,
• Tightness cannot be achieved,
• Disconnection may occur under excessive pressure.

This can lead to production stoppages, machine damage, and even personnel injuries.

4. DIN EN ISO 228-1 Standard and Marking

This standard, which came into force by the end of 2024, mandates the visual distinction of parallel pipe threaded connections. Connections with inches of thread should be identified by the indentation mark to the switch plane, for example.

Figure 1. Sample markup (simulated)

5. Practice and Recommendations

• Technical Trainings: It is recommended that technicians working in the field be trained in dental type recognition.
• Measurement Tools: Thread gauge should be used.
• Use of Marked Products: Marked fasteners should be preferred for new purchases.
• Labeling Systems: Systems such as color coding can be used in storage and stock management.

6. Conclusion

Hydraulic system safety is possible not only with high-quality components, but also with correctly matched connections. The distinction of tooth types is an element that may seem small but directly affects the integrity of the system. The DIN EN ISO 228-1 standard is an important step to facilitate this process. However, success in practice is only possible with the transfer of technical knowledge to the field.