TM 5-6640-212-14
(8) Observe the dial reading. To read the depth of
b. Operation.
penetration, push down the depth gage rod gently as far
as it will go. The dial reading indicates depth of
(1) Level the instrument carefully by means of the
penetration in tenths of millimeters. For example, if the
leveling screws in the base, sighting the spirit level.
dial needle rests at the fourth mark past the 270 point,
penetration depth is 27.4 millimeters. On depths greater
(2) Insert the cone (stored in drawer Al, fig.
than 38 millimeters, the dial needle makes more than
B-7) into the chuck and tighten securely.
one complete revolution to a maximum depth of 39
millimeters on a single reading.
(3) Set the dial pointer to zero. Grasp the test rod,
release the clutch trigger, and raise the test rod as high
(9) Return the dial needle to zero. If the original
as possible. If dial reading is not exactly zero, adjust the
zero setting has been accurate, the dial needle will return
reading to zero by means of the zero adjusting screw.
exactly to zero, and subsequent readings will check
Should this adjustment fail to bring dial pointer to zero,
against standard gage blocks.
set the zero adjusting screw to approximately midposition
and draw the depth gage rod to its Uppermost or stop
(10)Consult ASTM Methods D217 (TM 10-1166) for
position. Remove the dial rim and glass and loosen the
detailed descriptions of test procedures using
knurled thumb nut. Reset the dial pointer to zero and
penetrometer.
tighten the thumb nut.
(4) Add weights to the test rod as required. In
2-32. Adding and Subtracting Machine
adding weights to make up the required test load, note
that the weight of the test rod itself is 47.5 grams. When
a Description. The adding and subtracting machine
the specified load for grease penetrations with a grease
(3, fig.
cone, for example, is 150 grams, no weights need be
requirements specified in ASTM Method D2270 (TM 10-
added, as the combined weight of the cone (102.5
1166). It is stowed in cabinet K3 (figs. 1-2 and B-16).
grams) and the test rod (47.5 grams) makes up the
The calculator is an eight-bank, hand operated machine
required load as specified by ASTM.
used for adding, subtracting, multiplying, and dividing.
b. Operating Controls and Parts.
(5) Place the prepared sample to be tested in
position on the penetrometer table.
(1) Upper dials. The upper dials are located in the
upper part of the movable carriage. These dials show
(6) Adjust the height of the penetrometer to bring
the quotient (answer) of a division problem in red figures;
the point of the penetrating instrument (cone) exactly into
they show the multiplier in black figures.
contact with surface of the sample as follows: (a) Place a
(2) Lower dials. These 16 dials are located in the
weak light to one side of the cone and follow the shadow
lower part of the carriage. These dials show the
formed by the penetrating instrument on the surface of
answers.
the sample until no light appears from the point.
(3) Carriage shift knob. This knob is located at the
(b) In adjusting the height of the penetrometer,
right end of the carriage. It is used for shifting several
release the lockscrew and make a coarse adjustment by
places at a time. Lift up on the knob and slide the
means of the coarse adjusting screw directly opposite
carriage to the desired position.
the lockscrew. Tighten the lockscrew securely.
(4) Clear-out crank. This is the smaller crank
located at the right end of the carriage. Turn clockwise
(c) Make final contact adjustment by means of
to clear the upper dials; turn counterclockwise to clear
the micrometer adjusting screw.
the lower dials.
(7) Release the test rod, allowing the penetrating
(5) Operating crank. This is the larger crank
instrument (cone) to descend into the sample. To
located on the right side of the machine. It is used in all
release the test rod, depress the clutch trigger and hold
operations and is turned either clockwise or
in its released position during the specified time required
counterclockwise, depending on the type of problem.
for the test, using a stopwatch. At end of this time,
release the clutch trigger quickly, allowing the test rod to
(6) Repeat and nonrepeat keys. These keys are
be locked instantly into position.
located on the right front face of the machine. The
repeat key is marked R. When the repeat key is
depressed, any figures set on the keyboard remain
2-53
