Practical Grinder Application; Maintenance And Inspection - Hitachi G10SS Instructions Manual

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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 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 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.
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(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. 2.
2. Disassembling
Follow the above procedures in reverse.
CAUTIONS
Confirm 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. 3)
The motor employs carbon brushes which are
consumable parts. Since an excessively worn carbon
brush can result in motor trouble, replace the carbon
brushes with new ones 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 ensue that they
slide freely within the brush holders.
4. Replacing carbon brushes:
Disassemble the brush caps with a slotted-head
screwdriver. The carbon brushes can then be easily
removed.
5. Replacing supply cord
If the replacement of the supply cord is necessary,
it has to be done by Hitachi Authorized Service
Center to avoid a safety hazard.
6. 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.
7. Service parts list
CAUTION
Repair, modification and inspection of Hitachi Power
Tools must be carried out by a Hitachi Authorized
Service Center.
This Parts List will be helpful if presented with the
tool to the Hitachi Authorized Service Center when
requesting repair or other maintenance.
In the operation and maintenance of power tools,
the safety regulations and standards prescribed in
each country must be observed.
MODIFICATIONS
Hitachi Power Tools are constantly being improved
and modified to incorporate the latest technological
advancements.
Accordingly, some parts may be changed without
prior notice.