Industrial Lubricants

NLGI classification

NLGI Number ASTM worked (60 strokes)
penetration at 25 °C
tenths of a millimetre
Appearance
000 445-475 fluid
00 400-430 semi-fluid
0 355-385 very soft
1 310-340 soft
2 265-295 "normal" grease
3 220-250 firm
4 175-205 very firm
5 130-160 hard
6 85-115 very hard

Common greases are in the range 1 through 3.

Those with a NLGI No. of 000 to 1 are used in low viscosity applications.

Examples include enclosed gear drives operating at low speeds and open gearing.

Grades 0, 1 and 2 are used in highly loaded gearing. Grades 1 through 4 are often used in rolling contact bearings.

Greases with a higher number are firmer, tend to stay in place and are a good choice when leakage is a concern.