The National Lubricating Grease Institute consistency scale. Each grade is a band of worked cone penetration in tenths of a millimetre at 25 C: NLGI 000 is semi-fluid at 445 to 475, NLGI 2, the everyday bearing grease, sits at 265 to 295, and NLGI 6 is a solid block at 85 to 115. Soft grades from 00 to 1 suit centralized systems and gearboxes, NLGI 2 covers most bearings, and stiffer grades go in vertical shafts and some high-speed bearings.
Auto-lube system wants NLGI grade 1, the 2 won't push through those long lines in winter.
Also heard as
- NLGI number
- grease grade
Do not mix it up with
- Viscosity: NLGI grade describes how stiff the grease is; base oil viscosity describes the oil inside it, and the two are chosen separately.
Related terms
Cone penetration
Depth a standard cone sinks into grease in five seconds, the basic measurement of consistency.
Grease
Semi-solid lubricant made of oil held in a thickener sponge, usually with additives.
Thickener
Solid structure in a grease, usually a metal soap or polyurea, that holds the base oil like a sponge.
Channeling
Grease pushed aside by rolling elements so it sits in shoulders beside the track instead of churning.