Originally posted by SPALDING GREEN
Isn't viscosity measured by pouring the oil through a hole of a certain size & timing how long it takes for a set amount to flow & then the oil can be graded?
There are a few ways of measuring oil viscosity , but from memory , I think the standard is having oil in a container , and a blender type device . The shaft is then spun at a set speed in the oil to measure the shearing rate. Thinner oils require less power to spin than the thicker oils . The viscosity level of the oil is then worked out from how much power is consumed to spin the shaft at a set speed in different grade oils .
Don't know if this test still applies these days .