Title: The Hidden Cost of "Close Enough": Why ISO 2768-fK Matters
This is the practical data engineers need. For a dimension with no individual tolerance callout, the permissible deviation depends on the nominal size of the feature. iso 2768 fk
The code "fK" combines a from Part 1 (f) and a tolerance class from Part 2 (K). Title: The Hidden Cost of "Close Enough": Why
A 45-degree chamfer with a 15 mm leg length must be machined to 45° ± 30 minutes (half a degree). A 45-degree chamfer with a 15 mm leg
The combination "fK" is the most common high-precision general tolerance specified for CNC-machined parts. While "mK" (Medium/Medium) is the default for general fabrication, "fK" is chosen when parts require tighter control.
| Class | Linear tolerance (e.g., 30–120 mm) | Geometric tolerance (e.g., 30–100 mm) | |-------|-------------------------------------|----------------------------------------| | | ±0.15 | 0.15 | | FH | ±0.15 | 0.30 | | MK | ±0.30 | 0.15 | | MH | ±0.30 | 0.30 |