2
UNPACKING & SETUP
• Inspect your Direct Shear Machine for damage,
remove from the pallet.
• Review connections section and install necessary
components.
• Assemble the dead weight lever arm. Remove all
packing material from arm and adjusting screw sup-
port bracket. Reposition the arm above the support
bracket holes and reinstall the support bracket. Next
install the 3.5in diameter counterbalance weight and
the weight platform.
CONNECTIONS
Vertical Displacement Rod
– Screws into the top plat-
form to the right of the rear pull-down rod.
Vertical Displacement Clamping Arm
– Attach to the
above rod.
Vertical Displacement Dial Gauge
– Consolidation –
Attach to the clamping arm with the screw provided.
Horizontal Displacement Dial Gauge
– Shear – At-
tach to the threaded rod on the angle bracket-top plat-
form, right front.
Load Cell
– Connect the load cell to the support cast-
ing at the right end of the direct shear using the two
knobs. Adjust the knobs so that the load cell is as far
to the right as possible. This will allow room for assem-
bling the water chamber and the shear rings with min-
imum interference. Connection is made at the rear of
the readout cabinet.
Water Chamber
– Special care should be taken to
see that the four (4) roller bearings between the water
chamber and the base slide tracks are properly cleaned
and contain a slight amount of oil during and after use.
We advise using a cover over the direct shear after
use to eliminate dust from entering the precision slide
assembly. The main drive shaft should be at its home
position. This will place the sample load pad in the cen-
ter of the crossarm for consolidation.
Shear Boxes (sold separately)
– The shear boxes
are held together with (2) stainless steel screws. There
are also (4) screws for adjusting the gap between the
rings once consolidation has been reached. The gap
is adjusted by turning the screws clockwise from the
finger tight position. One full turn will give .031” gap.
There is a line scribed on the adjusting knob for deter-
mining how much gap each screw has provided. The
screws should be turned evenly to maintain a proper
gap. At the bottom of each screw is a nylon glide which
keeps the top shear ring from dropping during the test.
FRONT PANEL CONTROLS
The strain rate is controlled from the front panel thumb-
wheels. Machine must be plugged in to a properly wired
grounded receptacle with appropriate electrical current.
PANEL CONTROLS — POWER & SHEAR RATE
Power Switch
– An indicator light is present when
power is turned on.
Strain Rate Selector
– The strain rate is set with
thumbwheel selectors. The switches are direct reading
in inches/minute with an implied leading decimal point.
Once the rate is set and the test is started, the switch
setting is ignored until the stop switch is pressed or a
limit switch is tripped.
Limit Switches
– These switches are located on the
platform behind the water chamber.
Adjustment of these switches is made by loosening the
Phillips-head screws and moving the limit switch as-
sembly in the direction desired. The home position has
been set so that the load crossarm is in the middle of
the shear rings.
Note: The limit of travel of the drive shaft is dependent
on the limit switch settings. Do not operate the drive
motor with the water chamber disconnected because
this will make the limit switches inoperable.
Weight Sets are required to apply the consolidation load and are available in both Pound and Kilogram sets.
Pound Weight Sets
Model
Total Mass
Total Load at 10:1
Beam Ratio¹
Included Weight Sets
0.852lb (1/8tsf)
1.704lb (1/4tsf)
3.409lb (1/2tsf)
6.818lb (1tsf)
13.635lb (2tsf)
27.270lb (4tsf)
HMA-727
HMA-732
HMA-729
54.5lb
109.1lb
218.2lb
545lbf (8tsf)
1,091lbf (16tsf)
2,182lbf (32tsf)
2
2
2
1
1
1
1
1
1
1
1
1
1
1
1
1
3
7
¹tsf values indicate force applied to a 2.50in diameter specimen using a 10:1 beam ratio.
Kilogram Weight Sets
Model
Total Mass
Total Load at 10:1
Beam Ratio
Included Weight Sets
1kg
4kg
8kg
HMA-730
HMA-725
HMA-731
32kg
64gk
88kg
320kg
640kg
880kg
4
4
4
3
5
5
2
5
8
