Maintenance And Inspection - Hitachi Koki G 12SA2 Mode D'emploi

English
PRACTICAL GRINDER APPLICATION
1. Pressure
To prolong the life of the machine and ensure a
first class finish, it is important that the machine
should not be overloaded by applying too much
pressure. In most applications, the weight of the
machine alone is sufficient for effective grinding.
Too much pressure will result in reduced rotational
speed, inferior surface finish, and overloading which
could reduce the life of the machine.
2. Grinding angle
Do not apply the entire surface of the depressed
center wheel to the material to be ground. As
shown in Fig. 1, the machine should be held at an
angle of 15° – 30° so that the external edge of the
depressed center wheel contacts the material at an
optimum angle.
3. To prevent a new depressed center wheel from
digging into the workpiece, initial grinding should
be performed by drawing the grinder across the
workpiece toward the operator (Fig. 1 direction B).
Once the leading edge of the depressed center
wheel is properly abraded, grinding may be
conducted in either direction.
4. 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.
CAUTIONS
Check that the work piece is properly supported.
Ensure that ventilation openings are kept clear when
working in dusty conditions.
If it should become necessary 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 use, the power source
should be disconnected.
ASSEMBLING AND DISASSEMBLING THE
DEPRESSED CENTER WHEEL (Fig. 2)
CAUTION: Be sure to switch OFF and disconnect the
attachment plug from the receptacle to avoid
a serious accident.
1. Assembling (Fig. 2)
(1) Turn the equipment upsidedown so that the spindle
will be facing up.
(2) Mount the wheel washer onto the spindle.
(3) Fit the protuberance of the depressed center wheel
onto the wheel washer.
6
(4) Screw from above the wheel nut onto the spindle.
(5) As shown in Fig. 2, push in the push button to
prevent rotation of the spindle. Then, secure the
depressed center wheel by tightening the wheel nut
with the wrench.
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 loose, retighten them immediately. Failure
to do so could result in serious hazard.
3. Inspecting the carbon brushes (Fig. 4)
The motor employs carbon brushes which are
consumable parts. Since an excessively worn carbon
brush can result in motor trouble, replace the carbon
brush with a new one having the same carbon
brush No. shown in the figure when it becomes
worn to or near the "wear limit". In addition, always
keep carbon brushes clean and ensure that they
slide freely within the brush holders.
4. Replacing carbon brushes (Fig. 5)
<Disassembly>
(1) Loosen the D4 tapping screw retaining the tail cover
and remove the tail cover.
(2) Use the auxiliary hexagonal wrench or small
screwdriver to pull up the edge of the spring that
is holding down the carbon brush. Remove the
edge of the spring toward the outside of the brush
holder.
(3) Remove the end of the pig-tail on the carbon brush
from the terminal section of brush holder and then
remove the carbon brush form the brush holder.
<Assembly>
(1) Insert the end of the pig-tail of the carbon brush
in the terminal section of brush holder.
(2) Insert the carbon brush in the brush holder.
(3) Use the auxiliary hexagonal wrench or small
screwdriver to return the edge of the spring to the
head of the carbon brush.
(4) Mount the tail cover and tighten the D4 tapping
screw.
5. Maintenance of the motor
The motor unit winding is the very "heart" of the
power tool. Exercise due care to ensure the winding
does not become damaged and/or wet with oil or
water.
6. Service parts list
A: Item No.
B: Code No.
C: No. Used
D: Remarks