in order to "work" the sample in the container.
One cyclic movement of the plunger up and
down is known as a "double stroke." The grease
worker is fitted with a thermometer to provide a
check on the sample temperature.
One cyclic movement of the plunger up and
down is known as a "double stroke." The grease
worker is fitted with a thermometer to provide a
check on the sample temperature.
Additional apparatus includes a water bath for
bringing the grease to the proper temperature,
and a standard cutter for use in cutting samples
of block grease.
bringing the grease to the proper temperature,
and a standard cutter for use in cutting samples
of block grease.
Procedure: The initial procedure depends on
the type of penetration to be determined. Un-
disturbed penetration requires only the opening
of the grease container; unworked penetration
requires transfer of the sample to the test cup.
Worked and prolonged worked penetrations
involve first the transfer of the sample to the
cup, followed by the working procedure. Block
penetration requires the cutting of a sample with
the grease cutter. Sample size should be about
1 pound for most penetration determinations.
For block penetration, a 2-inch cube is the re-
quired sample. Samples are brought to 77° F in
either the water bath or an air bath (for block
penetration) before penetration is measured.
the type of penetration to be determined. Un-
disturbed penetration requires only the opening
of the grease container; unworked penetration
requires transfer of the sample to the test cup.
Worked and prolonged worked penetrations
involve first the transfer of the sample to the
cup, followed by the working procedure. Block
penetration requires the cutting of a sample with
the grease cutter. Sample size should be about
1 pound for most penetration determinations.
For block penetration, a 2-inch cube is the re-
quired sample. Samples are brought to 77° F in
either the water bath or an air bath (for block
penetration) before penetration is measured.
Following this initial procedure, the sample is
placed on the penetrometer platform. The cone
is placed in the zero position with its tip just
touching the surface of the sample. The cone is
released and allowed to drop for 5 seconds. The
penetration is read on the indicator in tenths of
a millimeter (A penetration of 200 means that
the cone moved 20.0 millimeters into the
grease). This procedure is performed three
times for each determination; the average of the
3 readings is recorded as the penetration.
placed on the penetrometer platform. The cone
is placed in the zero position with its tip just
touching the surface of the sample. The cone is
released and allowed to drop for 5 seconds. The
penetration is read on the indicator in tenths of
a millimeter (A penetration of 200 means that
the cone moved 20.0 millimeters into the
grease). This procedure is performed three
times for each determination; the average of the
3 readings is recorded as the penetration.
When only a small amount of grease can be
obtained, an alternate cone penetration method
is available. ASTM D 1403, "Cone Penetration
of Lubricating Grease Using One-Quarter and
One-Half Scale Cone Equipment," may be used
for samples as small as 5 grams.
obtained, an alternate cone penetration method
is available. ASTM D 1403, "Cone Penetration
of Lubricating Grease Using One-Quarter and
One-Half Scale Cone Equipment," may be used
for samples as small as 5 grams.
Significance: If a grease is too soft, it may not
stay in place, resulting In poor lubrication. If a
grease Is too hard, it will not flow properly, and
either fail to provide proper lubrication or cause
difficulties in dispensing equipment. These
statements sum up the reasons for classifying
greases by consistency. Penetration numbers
are useful for classifying greases according to
the consistencies required for various types of
service, and in controlling the consistency of a
given grade of grease from batch to batch.
stay in place, resulting In poor lubrication. If a
grease Is too hard, it will not flow properly, and
either fail to provide proper lubrication or cause
difficulties in dispensing equipment. These
statements sum up the reasons for classifying
greases by consistency. Penetration numbers
are useful for classifying greases according to
the consistencies required for various types of
service, and in controlling the consistency of a
given grade of grease from batch to batch.
NLGL Grade
Worked Penetration
Range mm/10
000 ................................................ 445-475
00 .................................................. 400-430
0 .................................................... 355-385
1 .................................................... 310-340
2 .................................................... 265-295
3 .................................................... 220-250
4 .................................................... 175-205
5 .................................................... 130-160
6 ...................................................... 85-115
00 .................................................. 400-430
0 .................................................... 355-385
1 .................................................... 310-340
2 .................................................... 265-295
3 .................................................... 220-250
4 .................................................... 175-205
5 .................................................... 130-160
6 ...................................................... 85-115
The National Lubricating Grease Institute has
classified greases according to their worked
penetrations. These NLGI grades, shown in the
accompanying table, are used for selection of
greases in various applications.
classified greases according to their worked
penetrations. These NLGI grades, shown in the
accompanying table, are used for selection of
greases in various applications.
In comparing greases, worked and prolonged
worked penetrations are generally the most
useful values. The change in penetration be-
tween the 60-stroke value and prolonged worked
value is a measure of grease stability.
Prolonged worked penetrations should report the
amount of working (10,000 and 100,000 strokes
are most common) in order to be useful.
worked penetrations are generally the most
useful values. The change in penetration be-
tween the 60-stroke value and prolonged worked
value is a measure of grease stability.
Prolonged worked penetrations should report the
amount of working (10,000 and 100,000 strokes
are most common) in order to be useful.
A-9 (FIST 2-4 11/90)