Tolerances
BS 970: Part 1: 1991: Table 13: Tolerances for Hot Rolled Round and Square Bar and Rough Turned Rounds.
| Size | Permitted Variation | |||||
|---|---|---|---|---|---|---|
| General Applications | Special Applications | |||||
| Primary Re-Rolled Round Material | Re-Rolled Material | Re-Rolled Material | ||||
| Diameter | Out of Section* | Diameter or Width Across Flats | Out of Section* | Diameter or Width Across Flats | Out of Section* | |
| mm | ± mm | mm | ± mm | mm | ± mm | mm |
| ≤ 16 | - | - | 0.2 | 0.3 | 0.2 | 0.3 |
| > 16 ≤ 26 | - | - | 0.3 | 0.5 | 0.2 | 0.3 |
| > 26 ≤ 38 | - | - | 0.4 | 0.6 | 0.25 | 0.4 |
| > 38 ≤ 51 | - | - | 0.5 | 0.8 | 0.3 | 0.5 |
| > 51 ≤ 64 | - | - | 0.6 | 0.9 | 0.4 | 0.6 |
| > 64 ≤ 76 | - | - | 0.7 | 1.1 | 0.5 | 0.8 |
| > 76 ≤ 90 | 1.3 | 2.0 | 0.7 | 1.1 | ||
| > 90 ≤ 120 | 1.5 | 2.3 | 0.8 | 1.2 | ||
| > 120 ≤ 160 | 2.0 | 3.0 | ||||
| > 160 ≤ 200 | 2.5 | 3.8 | ||||
| > 200 | 3.0 | 4.5 | ||||
* In relation to this table, the definition of 'out of section' is as follows :-
Round Bar : The difference between the maximum and the minimum diameter of the bar measured at the same cross section.
Square Bar : The difference between the two dimensions measured across the two pairs of opposing (parallel) sides at a common cross-section of the bar.
Note : By agreement between purchaser and supplier, the tolerances may be all plus or all minus, e.g. The general applications tolerance for 16mm diameter bar.
BS 970: Part 1: 1991: Table 15: Tolerances for Hot Rolled Flat bar
| Size | Permitted Variation | |
|---|---|---|
| General Applications | Special Applications | |
| Width | ± mm | ± mm |
| ≥ 10 ≤ 35 | 0.5 | 0.4 |
| > 35 ≤ 75 | 0.8 | 0.6 |
| > 75 ≤ 100 | 1.0 | 0.7 |
| > 100 ≤ 125 | 1.3 | 0.9 |
| > 125 ≤ 150 | 1.5 | 1.0 |
| Thickness | ± mm | ± mm |
| ≤ 10 | 0.4 | 0.3 |
| > 10 ≤ 20 | 0.5 | 0.3 |
| > 20 ≤ 40 | 0.6 | 0.4 |
| > 40 ≤ 60 | 0.8 | 0.5 |
| > 60 | 1.0 | 0.7 |
NOTE: By agreement between purchaser and supplier, the tolerances may be all plus or all minus, e.g. the standard tolerance on width for 35mm wide flats may be either plus 0.1mm or minus 0.1mm
