Machinery Lubrication July August 2008

NLGI UPDATE
Introducing the
Latest Word on Grease
BY DAVID COMO, DOW CORNING CORPORATION
Are you aware that some calcium-thickened greases may
start to melt and break down at 95°C (200°F), while
some complex or clay-thickened greases can approach
260°C (500°F) intact? Did you know that polyurea-thickened
greases are inherently less susceptible to oxidation than
their metal ion-containing brethren thickened with soaps?
How about the historical fact that traces of materials
similar to those used to form today’s complex greases were
found on chariot hubs from as far back as 1400 B.C.? These
bits of information and more can be found in one compact
and easy-to-understand handbook, the NLGI Lubricating
Grease Guide (LGG), which was originally published nearly
25 years ago.
In the past, matters of lubrication training on the shop
floor had been left to either the technician being replaced or
the guy working at the next bench. It happened similarly in
the original equipment (OE) design area. This results in
untrained people passing on their practices to other
untrained people, which invariably leads to misinterpretation
and miscommunication.
For Reference
With today’s reduction in workforce and budgets, and
higher pressure on uptime, little time is allowed for comprehensive
training in the workplace. As a result, more of those
budgets is being spent on “fighting fires”. Much of this time
and expense is attributable to failures due to lubricationrelated
failures. The LGG is not intended to replace quality
intensive training, such as that offered by organizations like
NLGI and Noria Corporation, but rather The Guide serves as
a supplement and reference for that information.
NLGI has now published its fifth edition of the NLGI
Lubricating Grease Guide (LOCCN: 84-61641; ISBN: 0-
9613935-1-3) which contains nine chapters of easily
accessible information covering topics from historical and
technical aspects differentiating greases to the manufacture,
testing, application and troubleshooting of lubricating
greases. It has been the first source of technical information
for anyone either entering the grease industry or involved in
daily maintenance operations – as well as a regular reference
for those of us who have been in the business for a while.
Chapters of Insight
The first four chapters give the reader a fundamental
background of where grease comes from historically, what
goes into making it, how it is tested for quality and
performance, and how the various combinations of grease
thickeners and base oils compare. Technically minded but
chemically challenged folks will find that the chemistry of
what goes into a grease is both accessible and sensible, and
this is covered in a painless three or four pages. It is good to
have a basic understanding of this material, even for
mechanical-type personnel.
The manufacturing chapter is interesting from the standpoint
that there are quite a number of ways to produce the
grease, and there are a variety of downstream processes
possible. It’s almost as interesting as visiting an actual
grease manufacturing plant in person. The chapter on
testing is good reference as well, especially when you’re
trying to decipher what a grease supplier is calling out on its
technical data sheets.
The following four chapters discuss when grease is used
(vs. oils), which grease to use when, how to handle and
dispense it, and some thoughts on troubleshooting problems.
This is the “good stuff” for those of us who are
actually specifying or choosing and using the grease. What
will one thickener type do better or poorer than another (for
example, calcium vs. lithium soap)? Which grease is a
food–grade grease? What about water resistance? What are
the principal uses of the different grease types?
54 July - August 2008 machinerylubrication.com Machinery Lubrication