Mooney viscometers are supplied with two standard rotors differing only in diameter. The large rotor is 38.10±0.03 mm in diameter and the small rotor has a diameter of 30.48±0.03 mm.
There is no unique conversion factor to convert the MS to the ML value. It must be established for each rubber. An approximate factor of 1.8 may be used to convert MS to ML if a high degree of precision is not required.