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NLGI Grease Grades


National Lubricating Grease Institute or NLGI describes the various grease grades primarily based on viscosity and, specifically, working penetration testing. This testing involves a rather elaborate machine that tests the reaction of grease penetration of a known weighted cone shaped device.  

Grease grades 000 through 1 are rather liquid in appearance and lower in viscosity. As the grades increase in number, so does the viscosity of the grease until it reaches the number 6 which is a solid. Greases above 2 are more viscous and those below 2 are less. Check out the chart below*. It gives a quick rundown of the various grease NLGI grades, working penetration results, appearance, and a food analogy. If you wish to know more about greases generally, Google and Wikipedia are great starts.

NLGI Grade


Worked penetration after

60 Strokes at 25° C (0.1mm)


Appearance

Consistency Food Analogy

000

445-475

fluid

cooking oil

00

400-430

semi-fluid

applesauce

0

355-385

soft

brown mustard

1

310-340

very soft

tomato paste

2

265-296

"normal" grease

peanut butter (yum!)

3

220-250

firm

vegetable shortening

4

174-205

very firm

frozen yogurt (tasty!)

5

130-160

hard

smooth pate

6

85-115

very hard

cheddar cheese


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