Practical Grinder Application; Maintenance And Inspection - Hitachi Koki G 12SE2 Handling Instructions Manual

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6. Conducting a trial run
Ensure that the abrasive products is correctly
mounted and tightened before use and run the tool
at no-load for 30 seconds in a safe position, stop
immediately if there is considerable vibration or if
other defects are detected.
If this condition occurs, check the machine to
determine the cause.
7. Confirm the push button.
Confirm that the push button is disengaged by
pushing push button two or three times before
switching the power tool on (See Fig. 1).
8. Fixing the side handle
Screw the side handle into the gear cover.

PRACTICAL GRINDER APPLICATION

1. Pressure:
To prolong the life of the grinder and ensure a first
class finish, it is important that the grinder should
not be overloaded by applying too much pressure.
In most applications, the weight of the grinder
alone is sufficient for effective grinding.
Too much pressure will result in reduced rotation
speed, inferior surface finish, and overloading which
could reduce the lift of the grinder.
2. Grinding angle
Do not apply the entire surface of the depressed
center wheel to the material to be ground. As
shown in Fig. 3, the grinder should be held at an
angle of 15°–30° so that the external edge of the
grinding wheel contacts the workpiece at an
optimum angle.
3. To prevent a new grinding wheel from digging into
the workpiece, initial grinding should be performed
by drawing the grinder across the workpiece toward
the operator (Fig. 3 direction B). Once the leading
edge of the depresssed center wheel is properly
abraded, grinding may be conducted in either direction.
4. Switch operation
[When the switch has locking mechanism]
Switch ON: To switch on, slide the lock lever in
thedirection of A and press the paddle
lever in the direction of B as shown
in Fig. 4-a. Furthermore, slide the lock
lever in the direction of C shown in
Fig. 4-b while pressing the paddle lever
to lock and enable continuous operation.
Switch OFF: To release the locking mode, press the
paddle lever in the direction of B shown
in Fig. 4-a, and release the paddle lever
to switch off.
[When the switch has no locking mechanism]
To switch on, slide the lock lever in the direction
of A and press the paddle lever in the direction
of B as shown in Fig. 4-a. Release the paddle
lever to switch off.
NOTE: The paddle lever can not be locked.
5. Precautions immediately after finishing operation
The wheel continues to rotate after the tool is
switched off.
After switching off the machine, do not put it down
until the depressed center wheel has come to a
complete stop. Apart from avoiding serious
accidents, this precaution will reduce the amount
of dust and swarf sucked into the machine.
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CAUTION
Check that the work piece is properly supported.
Ensure that ventilation openings are kept clear when
working in dusty conditions.
If it should become neccessary to clear dust, first
disconnect the tool from the mains supply (use non-
metallic objects) and avoid damaging internal parts.
Ensure that sparks resulting from use do not create
a hazard e.g. do not hit persons, or ignite flammable
substances.
Always use protective safety glasses and hearing
protectors, use other personal protective equipment
such as gloves, apron and helmet when necessary.
Always use eye and ear protection.
Other personal protective equipment such as dust
mask, gloves, helmet and apron should be worn
when necessary.
If in doubt, wear the protective equipment.
When the machine is not in use, the power source
should be disconnected.
ASSEMBLING AND DISASSEMBLING THE
DEPRESSED CENTER WHEEL (Fig. 1)
CAUTION: Be sure to switch power OFF and disconnect
the attachment plug from the power
receptacle to avoid serious trouble.
1. Assembling (Fig. 1)
(1) Turn the disc grinder upsidedown so that the spindle
is facing upward.
(2) Align the across flats of the wheel washer with the
notched part of the spindle, then attach them.
(3) Fit the protuberance of the depressed center wheel
onto the wheel washer.
(4) Screw the wheel nut onto the spindle.
(5) While pushing the push button with one hand, lock
the spindle by turning the depressed center wheel
slowly with the other hand.
Tighten the wheel nut by using the supplied wrench
as shown in Fig. 1.
2. Disassembling
Follow the above procedures in reverse.
CAUTIONS:
Comfirm that the depressed center wheel is mounted
firmly.
Confirm that the push button is disengaged by
pushing push button two or three times before
switching the power tool on.

MAINTENANCE AND INSPECTION

1. Inspecting the depressed center wheel
Ensure that the depressed center wheel is free of
cracks and surface defects.
2. Inspecting the mounting screws
Regularly inspect all mounting screws and ensure
that they are properly tightened. Should any of the
screws be loosened, retighten them immediately.
Failure to do so could result in serious hazard.
3. Inspecting the carbon brushes (Fig. 5)
The Motor employs carbon brushes which are
consumable parts.
When they become worn to or near the "wear
limit", it could result in motor trouble. When an
auto-shop carbon brush is equipped, the motor will
stop automatically.