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Grease

Other Names: Lubricating grease, automotive grease, bearing grease, etc. For hot cooking grease see Cooking Oils, Hot.

Viscosity: From 2,100 cPs. to several hundred thousand cPs. There are several different grades of greases running from an NLGI grade of 000 up through grade #6. NLGI is the National Lubricating Grease Institute. The smaller the grade number, the less viscous the grease. The viscosity of grease is often indicated by penetration number as determined by the distance a plumb bob of a known weight will sink into the surface of the grease during a given time period; thus, the higher the penetration number, the softer the grease, e.g., a number 1 grade grease has a penetration range from 310 to 340, while a number 4 grease has a penetration range of 175-205.

Remarks: Lubricating greases are generally mixtures of a mineral oil with one or more metallic soaps; the most common soaps are those of sodium, calcium, barium, aluminum, lead, lithium, potassium and zinc. The texture of grease may be smooth, buttery, ropy, fibrous, spongy or rubbery. Texture does not necessarily indicate the viscosity.

Pump Notes: Cast iron construction is satisfactory. Buna n elastomers are recommended. Shaft packing is normally used although a mechanical shaft seal may be used if viscosity permits. Grease is normally shear thinning so special attention must be paid to pump port sizing and motor sizing for correct horsepower.