Several turning tests with straight-edged carbon steel tools were run in order to investigate the influence of the cooling effect of cutting fluids upon the tool life. Finally it was found out that the relationship between tool temperature (0°C) and tool life (Tmin.) is θT1/m=C, which was derived in dry machining tests and is held well also in wet machining.
So that the tool temperature under a definite machining condition can be an index for evaluation of cutting fluids.