Flatness Stripes
Straight Edges
Straight edges (straightedges) are classified into four accuracy levels Grades, according to the DIN 874 standard. These levels define the permissible deviation (tolerance) on the flat surface of the bar.
- Grade 00: The highest accuracy. Used in metrology laboratories and precision applications where an extremely high flat surface is required.
- Grade 0: Very high accuracy, suitable for laboratory and industrial measurements where precise parallelism and a flat surface are required.
- Grade 1: Industrial accuracy, suitable for maintenance, inspection, and machine alignment tasks where high accuracy is desirable but not absolutely critical.
- Grade 2: Standard accuracy, sufficient for general alignment applications and checking mechanical parts in less demanding applications.
Tolerance Table by Grade
| Length | GG00 | GG0 | GG1 | GG2 |
|---|---|---|---|---|
| 300 mm | 2 μm | 5 μm | - | - |
| 500 mm | 4 μm | 7 μm | 12 μm | 21 μm |
| 750 mm | 6 μm | 9.5 μm | 17 μm | 27 μm |
| 1000 mm | 8 μm | 12 μm | 21 μm | 33 μm |
| 1500 mm | 11 μm | 17 μm | 29 μm | 46 μm |
| 2000 mm | 14 μm | 22 μm | 37 μm | 58 μm |
| 2500 mm | - | 27 μm | 46 μm | 71 μm |
| 3000 mm | - | 32 μm | 54 μm | 83 μm |
| 4000 mm | - | 42 μm | 71 μm | 108 μm |
| 5000 mm | - | 52 μm | 87 μm | 133 μm |
| 6000 mm | - | 62 μm | 104 μm | 158 μm |
