En Iso 13920-bf (95% Popular)

The standard is broken down into three main data tables that engineers use to check compliance:

The classes are independent of each other, meaning a drawing can call for a high-precision size (e.g., class B) while still allowing for a wider tolerance on shape (e.g., class F). This is exactly what the combination signifies: class B for dimensions (lengths & angles) and class F for geometry (shape & position) . The specification ISO 2768-mk is used for a similar purpose but for machined parts, while ISO 13920-BF is used explicitly for welded constructions . en iso 13920-bf

| Nominal Angle Leg Length (mm) | Permitted Deviation (Class B) | | :--- | :--- | | Up to 400 | ± 30 minutes (± 0.5°) | | 400 to 1,000 | ± 20 minutes (± 0.33°) | | Over 1,000 | ± 15 minutes (± 0.25°) | The standard is broken down into three main

EN ISO 13920 uses four tolerance classes, each representing a different level of workshop accuracy, ranging from fine (class A) to very coarse (class D). However, a key feature of the standard is its use of two independent sets of classes to control different aspects of a welded part: | Nominal Angle Leg Length (mm) | Permitted

This class specifically governs the geometric tolerances of the weldment, including how straight a part is or how flat a surface must be. 2. Tolerance Tables for Class B (Linear & Angular)

is a specific technical designation used in engineering drawings to define general tolerances for welded constructions. It combines two distinct precision levels from the ISO 13920 standard to ensure that welded parts fit together correctly without needing individual, complex dimensioning for every single weld. Breaking Down the Code: "BF"