Operation; Maintenance - Makita GA5020 Instruction Manual

box. Then rotate the wheel guard around to the position
shown in the figure. Tighten the lever to fasten the wheel
guard. If the lever is too tight or too loose to fasten the
wheel guard, loosen or tighten the screw to adjust the
tightening of the wheel guard band.
To remove wheel guard, follow the installation procedure
in reverse.
Installing or removing depressed center
grinding wheel/Multi-disc (accessory)
WARNING:
• Always use supplied guard when depressed center
grinding wheel/Multi-disc is on tool. Wheel can shatter
during use and guard helps to reduce chances of
personal injury. (Fig. 12)
Mount the inner flange onto the spindle. Fit the wheel/disc
on the inner flange and screw the lock nut onto the
spindle.
To tighten the lock nut, press the shaft lock firmly so that
the spindle cannot revolve, then use the lock nut wrench
and securely tighten clockwise. (Fig. 13)
To remove the wheel, follow the installation procedure in
reverse.

OPERATION

WARNING:
• It should never be necessary to force the tool. The
weight of the tool applies adequate pressure. Forcing
and excessive pressure could cause dangerous wheel
breakage.
• ALWAYS replace wheel if tool is dropped while
grinding.
• NEVER bang or hit grinding disc or wheel onto work.
• Avoid bouncing and snagging the wheel, especially
when working corners, sharp edges etc. This can
cause loss of control and kickback.
• NEVER use tool with wood cutting blades and other
sawblades. Such blades when used on a grinder
frequently kick and cause loss of control leading to
personal injury.
CAUTION:
• After operation, always switch off the tool and wait until
the wheel has come to a complete stop before putting
the tool down.
Grinding and sanding operation (Fig. 14)
ALWAYS hold the tool firmly with one hand on rear handle
and the other on the side handle. Turn the tool on and
then apply the wheel or disc to the workpiece.
In general, keep the edge of the wheel or disc at an angle
of about 15 degrees to the workpiece surface.
During the break-in period with a new wheel, do not work
the grinder in the B direction or it will cut into the
workpiece. Once the edge of the wheel has been rounded
off by use, the wheel may be worked in both A and B
direction.
Operation with abrasive cut-off/diamond
wheel (optional accessory) (Fig. 15)
The direction for mounting the lock nut and the inner
flange varies by wheel thickness.
Refer to the table below. (Fig. 16)
WARNING:
• When using an abrasive cut-off/diamond wheel, be
sure to use only the special wheel guard designed for
use with cut-off wheels.
• NEVER use cut-off wheel for side grinding.
• Do not "jam" the wheel or apply excessive pressure. Do
not attempt to make an excessive depth of cut.
Overstressing the wheel increases the loading and
susceptibility to twisting or binding of the wheel in the
cut and the possibility of kickback, wheel breakage and
overheating of the motor may occur.
• Do not start the cutting operation in the workpiece. Let
the wheel reach full speed and carefully enter into the
cut moving the tool forward over the workpiece surface.
The wheel may bind, walk up or kickback if the power
tool is started in the workpiece.
• During cutting operations, never change the angle of
the wheel. Placing side pressure on the cut-off wheel
(as in grinding) will cause the wheel to crack and break,
causing serious personal injury.
• A diamond wheel shall be operated perpendicular to
the material being cut.

MAINTENANCE

CAUTION:
• Always be sure that the tool is switched off and
unplugged before attempting to perform inspection or
maintenance.
• Never use gasoline, benzine, thinner, alcohol or the
like. Discoloration, deformation or cracks may result.
The tool and its air vents have to be kept clean.
Regularly clean the tool's air vents or whenever the vents
start to become obstructed. (Fig. 17)
Replacing carbon brushes (Fig. 18)
Remove and check the carbon brushes regularly.
Replace when they wear down to the limit mark. Keep the
carbon brushes clean and free to slip in the holders.
Both carbon brushes should be replaced at the same
time. Use only identical carbon brushes.
Use a screwdriver to remove the brush holder caps.
Take out the worn carbon brushes, insert the new ones
and secure the brush holder caps. (Fig. 19)
After replacing brushes, plug in the tool and break in
brushes by running tool with no load for about 10 minutes.
Then check the tool while running and electric brake
operation when releasing the switch trigger. If electric
brake is not working well, ask your local Makita service
center for repair. (For models GA5020/GA6020)
To maintain product SAFETY and RELIABILITY, repairs,
any other maintenance or adjustment should be
performed by Makita Authorized Service Centers, always
using Makita replacement parts.
ACCESSORIES
CAUTION:
• These accessories or attachments are recommended
for use with your Makita tool specified in this manual.
The use of any other accessories or attachments might
present a risk of injury to persons. Only use accessory
or attachment for its stated purpose.
• Your tool is supplied with a guard for use with a
depressed center grinding wheel, multi-disc and wire
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