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4. Set the shear/strain rate with the thumbwheels on
the left side of the machine. Each number is set by
pushing the thumbwheel button, the rate is in inches
per minute (0001 = 0.0001 in/min).
5. Tare the horizontal displacement LVDT on channel
2 of the readout box. To begin shear, switch the DI-
RECTION toggle switch to the left towards the LIMIT
light.
6. The water chamber with shear box will continue to
move at the set rate until the limit switch is activated
or the STOP button is pressed.
7. Load and Shear Displacement will be displayed
on channels 1 and 2 of the digital readout box and
transferred to an Excel file or the Direct Shear Data
Acquisition Software on the users connected com-
puter.
8. At the test completion, switch the DIRECTION tog-
gle to the right towards the HOME light. Press the
stop button when Zero load is reached on the load
cell, channel 1 of the readout box.
8A. If Residual Shear values are needed, these can be
determined during this time.
9. Reduce the vertical load to Zero by adjusting the
Fairchild Pressure Regulator until Zero psi is
reached on the digital readout box.
10. The Shear Box can now be removed from the wa-
ter chamber and the sample can be inspected.
MAINTENANCE
Special care should be taken to see that the four roll-
er bearings between the water chamber and the base
slide track are properly cleaned and contain a slight
amount of oil during and after use. It is recommended
to cover the Direct Shear machine when not in use to
prevent dust buildup.
Empty the water chamber after each test to prevent
soil and sand buildup inside the chamber. The water
can be drained from the port or the chamber can be
removed from the Direct Shear Machine for thorough
cleaning.
ACCESSORIES
HMA-95 Pneumatic Shear Machine Rolling Cart
HMA-739 Shear Box Counterbalance
HMA-610 Direct/Residual Shear Data Acquisition
Software
4
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