Casting Tolerances
Castings tolerances are dependent on both the materials cast and the method of production used. General Tolerances for metal alloy castings are specified by the International Standards Organization, in their Standard ISO 8062 for SG (and Malleable) Iron castings, made in machine produced sand moulds. The appropriate grades are Casting Tolerance (CT) 8 to 12. The capability of our green sand plants enables us to offer castings conforming to Grade CT8. Castings produced in Hand or Airset moulds will conform to grade CT9. These 2 grades are detailed in the table below:
| Raw Casting Basic (mm) | Total Tolerance (mm) | ||
| Over | Up to and including | CT8 | CT9 |
| – | 10 | 1.0 | 1.5 |
| 10 | 16 | 1.1 | 1.6 |
| 16 | 25 | 1.2 | 1.7 |
| 25 | 40 | 1.3 | 1.8 |
| 40 | 63 | 1.4 | 2.0 |
| 63 | 100 | 1.6 | 2.2 |
| 100 | 160 | 1.8 | 2.5 |
| 160 | 250 | 2.0 | 2.8 |
| 250 | 400 | 2.2 | 3.2 |
| 400 | 630 | 2.6 | 3.6 |
| Mismatch (not to be added to values above) | 0.7 | 1.0 | |
