Practical Grinder Application; Maintenance And Inspection - Hitachi G 10SD2 Handling Instructions Manual

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4. Fitting and adjusting the wheel guard
The wheel guard is a protective device to prevent
injury should the depressed center wheel shatter
during operation. Ensure that the guard is properly
fitted and fastened before commencing grinding
operation. By slightly loosening the setting screw,
the wheel guard can be turned and set at any
desired angle for maximum operational effective-
ness. Ensure that the setting screw is thoroughly
tightened after adjusting the wheel guard.
5. Ensure that the depressed center wheel to be utilized
is the correct type and free of cracks or surface
defects. Also ensure that the depressed center wheel
is properly mounted and the wheel nut is securely
tightened, Refer to the section on "Depressed Center
Wheel Assembly"
6. Conducting a trial run
Before commencing grinding operation, the machine
should be given a trial run in a safe area to ensure
that it is properly assembled and that the depressed
center wheel is free from obvious defects.
Recommended trial runs'duration are as follows:
After replacing depressed center wheel
........................................... 3 minutes or more
Prior to starting routine work
............................................ 1 minute or more
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. 2).
3. Fixing the side handle.
Screw the side handle into the gear cover.

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 con-
ducted in either direction.
4. Precautions immediately after finishing operation
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 acci-
dents, this precaution will reduce the amount of
dust and swarf sucked into the machine.
CAUTION
When the machine is not in use, the power source
should be disconnected.
27
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.
(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. Fail-
ure to do so could result in serious hazard.
3. Inspecting the carbon brushes (Fig. 3)
The motor employs carbon brushes which are
consumable parts. Since an excessively worn car-
bon 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. 4):
<Disassembly>
(1) Loosen the D4 tapping screw retaining the tail cover
and remove the tail cover.
(2) Use the auxiliary hexagonal wrench or small screw-
driver 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 from 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 screw-
driver 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.