En Iso 13920-bf ((hot)) Jun 2026

(straightness, flatness, and parallelism). Class F is often used for structural assemblies where moderate precision is required. Summary of Tolerances

is the standardized technical designation used in manufacturing and structural engineering to specify general tolerances for welded constructions . It designates a combination of Class B (medium accuracy) for linear and angular dimensions, and Class F for form and position parameters like straightness, flatness, and parallelism. By stamping EN ISO 13920-BF directly onto an engineering drawing's tolerance block, designers instantly streamline production, ensure assembly alignment, and protect manufacturers from costly component rejections without having to note hundreds of individual deviations. Decoding the Code: What Does "BF" Mean? en iso 13920-bf

Q: What is the difference between EN ISO 13920-BF and other tolerance standards? A: EN ISO 13920-BF is specifically designed for welded constructions and parts, providing guidelines for the tolerancing of welded joints and assemblies. (straightness, flatness, and parallelism)

The "BF" combination is a popular choice. Class B for dimensions offers a practical middle ground, avoiding the high cost of extremely tight tolerances while providing sufficient accuracy for most applications. It is commonly used in rail vehicles, motor vehicles, crane construction, steel construction, and machine construction. It designates a combination of Class B (medium

The two letters in the designation refer to separate tables within the ISO standard. Each letter represents a specific degree of accuracy, ranging from fine to coarse.

Refers to the tolerance class for linear dimensions. Typically, ISO 13920 classifies these as A (Fine), B (Medium), C (Coarse), or D (Very Coarse). Class B represents a "medium" tolerance level.

In the ISO 13920 coding system, the second letter regarding geometrical tolerances is either C (Fine) or D (Medium). There is no "F" class for geometry.