National Lubrication Grease Institute (NLGI)

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The National Lubrication Grease Institute, or NLGI, is a non-profit organization that serves to promote information on the use and manufacture of lubricating grease products. Its members include companies from across the world that are involved in varying industries related to grease production, distribution, and use. However, you may know about NLGI not because of its organization, but instead because of NLGI grade or ratings of grease.

History of the National Lubrication Grease Institute (NLGI)

The founding members of the NLGI held their first meeting on June 29, 1933, in Chicago, Illinois. This meeting’s initiators included J.R. Battenfeld of Battenfeld Grease and Oil Corporation, W.H. Saunders of International Lubricant Corporation, and Guy Peters of Peters Oil Craft Incorporated.

Today, NLGI has more than 200 members from 26 different countries. These members include manufacturers of grease, additives, equipment, and lubricating systems. Also, other member companies are grease distributors, lubrication service providers, OEMs (original equipment manufacturers), lubricating grease users, researchers, educators, and more.

NLGI Grade

In the late 1930s, the NLGI created a standard system of classification of grease’s application consistency that is still being used today. This system assigns NLGI Consistency Numbers or NLGI Numbers 000 through 6, indicating grease consistency or hardness. Basically, the higher the number, the harder or less flowy the lubricating grease.

Knowing a lubricant’s NLGI grade should help you predict how the lubricant adheres, moves, or flows upon application. Furthermore, this knowledge then assists in planning and adjusting your lubrication process, frequency, and monitoring.

What are the Appropriate Applications According to NLGI Consistency Numbers?

  1. NLGI 000 – Described as having a consistency of ketchup, this grade of lubricating grease is ideal for lubricating sliding surfaces, guides, open-gear lubrication, etc.
  2. NLGI 00 – Slightly thicker than ketchup, this type of lubricating grease is also ideal for sliding surfaces, open gears, and spur gears with friction surface lubrication.
  3. NLGI 0 – Soft and still flowy, this NLGI grade is an excellent lubricant for loaded roller sliding bearings. It is also recommended to lubricate needles and multiple-row roller bearings, chains, and flexible chain couplings.
  4. NLGI 1 – Still soft with a texture like tomato paste, a lubricant with this grade is ideal for the  lubrication of needles and multiple-row roller bearings, automotive wheel bearings, and most electric drive applications
  5. NLGI 2 – Similar to peanut butter, this consistency of grease is ideal for multipurpose use. This grade is excellent for plain and anti-friction bearings operating under moderate load and at medium speeds.
  6. NLGI 3 – Semi-solid in appearance, this grade of grease is a common lubricant in automotive, industrial, marine, and agricultural applications. It has good sealing properties against pollution, corrosion, and environmental impact.
  7. NLGI 4 – Moderately stiff like frozen yogurt, this grade of grease is a common lubricant for water pumps. It also has uses in agricultural equipment and other high-speed, lightly loaded applications.
  8. NLGI 5 – Having a consistency of smooth pate, this grade is not common. It is used when a low score of bleeding or oil separation is required. For example, in overhead conductors and high-speed applications.
  9. NLGI 6 – The hardest and most uncommonly used grade, it is used for lubricating pillow block bearings and other high-speed applications where low bleeding or oil separation is necessary.

NLGI Grade Reference Chart

NLGI GradeWorked Penetration After 60 Strokes at 25°C (0.1mm)AppearanceFood Consistency Comparison
0355-385Very SoftBrown Mustard
1310-340SoftTomato Paste
2265-295Moderately SoftPeanut Butter
3220-250Semi-FluidVegetable Shortening
4175-205Semi-HardFrozen Yogurt
5130-160HardSmooth Pate
685-115Very HardCheddar Cheese Spread

What is the NLGI Certification?

The NLGI Certification is an identifying symbol that serves as a tag that classifies a lubricating grease’s suitability for use. This mark can indicate a lubricant for chassis-only or wheel-bearing use. Furthermore, with this certification, end-users, manufacturers, and distributors can quickly identify which lubricant they need for their particular purposes.

NLGI’s Commitment to Educating the Public

The National Lubrication Grease Institute’s commitment to educating the public on lubricating grease is shown through:

  • Holding annual meetings that are open to members and non-members interested in learning about grease and grease-related applications.
  • Organizing presentations during annual meetings that cover vital grease topics from manufacturing to applications, and human or environmental impact.
  • Offering panel discussions on various topics during the annual meetings.
  • Promoting networking and collaboration, thus providing opportunities for advancing technological innovation in grease-related fields of study.
  • Offering extensive and unique education programs for grease studies for beginners and advanced learners.
  • Developing and offering application and maintenance-related courses for machine users and marketing companies, thus expanding their knowledge on using and marketing grease products.
  • Hiring and training specialists in conducting presentations and educational courses on practical topics such as grease types and manufacturing, testing methods and results, base oils and additives, toxicology and safety, and new technologies for lubricating grease.

Other NLGI Services

Aside from establishing standards and updating methods, the NLGI also services the grease industry with its technical journal, NLGI Spokesman. This bi-monthly technical journal provides peer-reviewed scientific and technical content on grease manufacturing, new developments, and other current and relevant issues in the grease industry.

Additionally, NLGI conducts surveys to understand the grease industry further. NLGI also issues certifications to grease specialists, conducts academic outreach, and funds research grants. They have an extensive database of information available to the public and their member companies. Moreover, anyone who works in lubrication management or maintenance can turn to NLGI for information and guidance.

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