Orifice Size in Viscosity Cup

Q: What are the orifice sizes in the Ford viscosity cups?

A: According to ASTM D1200 the diameters are as follows:

Ford #1 = 1.90 mm
Ford #2 = 2.53 mm
Ford #3 = 3.40 mm
Ford #4 = 4.12 mm
Ford #5 = 5.20 mm

Hope this helps.

Regards,