It’s that chart every oil nerd pulls out when someone says “is AW-46 hydraulic the same viscosity as a 30W motor oil”?

Viscosity charts are used to determine whether or not lubricants will  have similar viscosities. If you’re used to working with one set of standards and another gets brought up, this wonderful work of art gives you a point of reference. 

The numbers in the middle of the chart are ISO Viscosity Grades, American Gear Manufacturers Association (AGMA) Grades, SAE Crankcase Oil Grades and SAE Gear Oil Grades. To use the chart, you read from side to side NOT up and down. So for example, an ISO grade hydraulic AW-46 has a viscosity similar to a 20W SAE grade, not 30W as mentioned above.