High viscosity lubricants result in high shear stresses. As a rule of thumb, the viscosity of a machine oil fall about 25% with every 10ºC temperature increase.

The Reynolds interpolation function is accurate in the vicinity of the reference points. The Vogel equation is most accurate over the whole range.

Normally the viscosities at 40 °C y 100 °C are taken from the data sheet as reference points, but any two temperatures and viscosities can be inserted.