DIN EN ISO 129-1:2022-02

Clearly Specify Dimensions and Tolerances in Technical Drawings

DIN EN ISO 129-1 specifies the fundamental rules for indicating dimensions and tolerances in technical product documentation (TPD). It describes how dimensions, dimension lines, dimension values, symbols and tolerance indications are to be presented unambiguously in technical drawings. The standard helps designers, technical drafters and CAD users communicate technical information consistently and clearly.

What Is DIN EN ISO 129-1 About?

The standard defines the general principles of dimensioning and tolerance indication for technical drawings and 3D applications. It focuses on rules for representing linear, angular, radial, diametrical and coordinate dimensions, as well as the correct use of dimension lines, extension lines, property indicators and dimensional tolerances. It also describes methods for dimensioning holes, threads, cones, repeated features, symmetries and complex geometries.

Topics Covered

• Fundamentals of technical dimensioning
• Dimension lines, extension lines and dimension values
• Indication of dimensional tolerances and limit deviations
• Diameter, radius, angle and coordinate dimensioning
• Dimensioning of holes, counterbores, cones and threads
• Repeated and equally spaced features
• Symmetrical workpieces and views
• Technical product documentation in 2D and 3D applications
• Marking notes and textual instructions

Practical Relevance

Unambiguous dimensioning is essential for the error-free implementation of technical drawings in manufacturing, assembly and inspection. DIN EN ISO 129-1 provides uniform rules for this purpose and helps companies avoid misunderstandings between design, manufacturing and quality assurance. This reduces manufacturing errors and improves the international comprehensibility of technical documentation.

The standard is particularly relevant for preparing standards-compliant technical drawings and using modern CAD and TPD systems. It supports the consistent use of dimensions, tolerances and graphical symbols throughout the entire product development process.

Changes Compared with DIN EN ISO 129-1:2020-02

The following changes have been made compared with the previous edition:

• Addition of the new representations in Figure 39 c) and Figure 39 d)
• Expansion of the associated explanations and rules
• Review and correction of various technical terms in the German version

Target Audience

• Designers and development engineers
• Technical drafters
• CAD users
• Quality managers
• Manufacturing engineers
• Mechanical engineering companies
• Inspection and measurement technicians
• Technical product documentation (TPD) professionals

Conclusion

DIN EN ISO 129-1 provides the central basis for the standards-compliant indication of dimensions and tolerances in technical drawings and product documentation. With its uniform dimensioning rules, it supports the unambiguous communication of technical requirements and improves cooperation between design, manufacturing and quality assurance.

This document replaces DIN EN ISO 129-1:2020-02 .