NLGI Grease Consistency Classification
The commonly used grease consistency classification is that established in the USA many years ago by the National Lubricating Grease Institute (NLG). This classifies greases solely in terms of their hardness or softness; no other property or performance level is taken into consideration.
The classification consists of a series of consistency range, each of which is defined by a number (or numbers) 000 to 6. The consistency, defined by the distance in tenths of a millimetre, that a standard cone penetrates a sample of the grease number under standard conditions at 25 degree. This system is used to classify industrial greases.
