ISO VG 68 Oil, AGMA 2, SAE 20 Oil

ISO VG stands for International Standards Organization Viscosity Grade. This classification is almost exclusively limited to industrial lubricants. AGMA stands for the American Gear Manufacturers Association - this specification is reserved for gear oils. SAE stands for the Society of Automotive Engineers. These all refer to specific testing methods to determine oil viscosities.

Some oils that may be classified as ISO VG 68 oil may also be classified as an AGMA 2 and/or SAE 20 oil. In other words, these oil classifications are interchangeable in their applications - however, it is best to consult OEM specifications to determine which lubricant specification is recommended for use.

ISO VG 68/SAE 20/AGMA 2 lubricants for industrial and (few) automotive applications are commonly employed in hydraulic systems, moderately-loaded and heavily-loaded gearboxes, food industry machinery, slide ways, and some air and gas compressors.

ISO VG 68 oil has a midpoint kinematic viscosity of 68 mm2/s, also referred to as centistokes (cSt). The midpoint is derived by taking the average of both the minimum and maximum kinematic viscosities. In the case of ISO VG 68 oil, those numbers are 61.2 cSt and 74.8 cSt, respectively. SAE 20W oil has a minimum high-temperature kinematic viscosity of 5.6 mm2/s (cSt). AGMA 2 lubricants have a minimum viscosity of 61.2 mPa.s and a maximum viscosity of 74.8 mPa.s. These numbers refer to the standard testing mechanisms used to determine how much resistance to flow (i.e. viscosity) these oils demonstrate.

Determining which weight of lubricant to implement in your machine is always an important and sometimes daunting task.

Click here to view or print the Comparative Viscosity Chart.

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