A Lubricant Viscosity Conversion Table is a reference chart used to compare the viscosity ratings of lubricants across different classification systems. These systems are used by various industries and organisations to grade lubricants based on their flow characteristics (viscosity), typically measured at specific temperatures.
The table helps users:
| System | Description |
|---|---|
| ISO VG | International standard for industrial oils, based on kinematic viscosity at 40°C. |
| SAE Motor Oil | Rating system by the Society of Automotive Engineers for engine oils. Uses numbers like 10W-30, where "W" means winter performance. |
| SAE Gear Oil | Similar to motor oil ratings but specifically for gear oils. Not directly equivalent to motor oil grades. |
| AGMA | Used for lubricants in gear systems, mainly in industrial applications. |
For example, if a machine manual calls for ISO VG 100 oil, but only SAE gear oil is available, the conversion table helps identify the closest SAE gear oil grade (like SAE 90).
You are maintaining an industrial gearbox in a manufacturing plant.
The manufacturer’s manual specifies:
“Use ISO VG 150 oil.”
However, your stockroom only carries oils labelled with SAE grades, and you need to find an equivalent.
1. Find ISO VG 150 in the first column of the table.
2. Check the corresponding values in the other columns:
3. Based on this, you can confidently select:
You’ve correctly matched the oil using the table and ensured that your gearbox will run with a lubricant of equivalent viscosity and performance.