Sharpening The Cutter Blades; Maintenance And Inspection - Hitachi P 20SB Handling Instructions Manual

○ Disassembling the back metal from the cutter blade is to
be made only at grinding the cutter blade.
2. Cutter blade assembly
CAUTION
○ Prior to assembly, thoroughly wipe off all swarf
accumulated on the cutter blade.
(1) Turn the fl at surface of the cutter block sideways,
and assemble the adjusted cutter blade as shown in
Fig. 7. Ensuring that the leaf spring on the cutter block
is correctly fi tted to the hole on the rear plate, push the
back of the cutter blade with a fi ngertip in the direction
indicated by the arrow, until the edge of the back metal
is properly fi tted to the cutter block surface. Correct
installation is illustrated in Fig. 8.
(2) Place the blade holder on the completed assembly,
as shown in Fig. 10, and fasten it with the three bolts.
Ensure that the bolts are securely tightened.
(3) Turn the cutter block over, and set the other side in the
same manner.
3. Adjustment of cutter blade height
CAUTION
○ As the set gauge has been accurately factory adjusted,
never attempt to loosen it.
(1) After attaching the back metal to the cutter blade,
temporarily fasten them together with machine screws,
as shown in Fig. 11.
(2) Insert the set gauge plate spring into the hole on the back
metal and heavily push the plate spring in the direction
indicated by the arrow in Fig. 12 until it snaps into the
correct position.
(3) Holding the set gauge with the blade edge facing
downward as shown in Fig. 13, loosen the temporarily
fastened machine screws and lightly push the cutter
blade with a thumb until the cutter blade gently touches
the plate.
CAUTION
○ Do not push the blade with excessive pressure.
Excessive pressure could cause maladjustment of the
blade height.
(4) Finally, retighten the machine screw to securely fasten
the cutter blade and the back metal, thereby completing
the blade height adjustment procedure.
(5) Holding the set gauge as shown in Fig. 14, push upward
on the back metal and remove it from the set gauge.
(6) The cutter blade is now ready to be mounted on the planer
as described in the section on cutter blade assembly.

SHARPENING THE CUTTER BLADES

Use of the optional accessory Blade Sharpening Ass'y is
recommended for convenience.
(1) Use of Blade Sharpening Ass'y
As shown in Fig. 15, two blades can be mounted on
the blade sharpening ass'y to ensure that the blade
tips are ground at equal angles. During grinding, adjust
the position of the cutter blades so that their edges
simultaneously contact the grinding stone as shown in
Fig. 16.
(2) Cutter blade sharpening intervals
Cutter blade sharpening intervals depend on the type of
wood being machined and the cutting depth. However,
sharpening should generally be eff ected after each 500
meters of cutting operation.
(3) Grinding allowance of the cutter blades
As illustrated in Fig. 17, a grinding allowance of 3.5 mm
is provided for on the cutter blade. That is, the cutter
blade can be repeatedly sharpened until its total height
is reduced to 24.5 mm.
(4) Grinding Stone
When a water grinding stone is available, use it after
dipping it suffi ciently in water since such a grinding stone
may be worn during grinding procedure, fl atten the upper
surface of the grinding stone as frequently as possible.

MAINTENANCE AND INSPECTION

1. Inspecting the cutter blades
Continued use of dull or damaged cutter blades will result
in reduced cutting effi ciency and may cause overloading
of the motor. Sharpen or replace the cutter blades as
often as necessary.
2. Handling
CAUTION
○ The front base, rear base, and cutting depth control
knob are precisely machined to obtain specifi cally high
precision. If these parts are roughly handled or subjected
to heavy mechanical impact, it may cause deteriorated
precision and reduced cutting performance. These parts
must be handled with particular care.
3. 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.
4. Inspecting the carbon brushes (Fig. 18)
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 fi gure 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.
5. Replacing carbon brushes
Disassemble the brush caps with a slotted-head
screwdriver. The carbon brushes can then be easily
removed.
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
A: Item No.
B: Code No.
C: No. Used
D: Remarks
CAUTION
Repair, modifi cation 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.
MODIFICATION
Hitachi Power Tools are constantly being improved
and modifi ed to incorporate the latest technological
advancements.
Accordingly, some parts (i.e. code numbers and/or
design) may be changed without prior notice.
NOTE
Due to HITACHI's continuing program of research and
development, the specifi cations herein are subject to change
without prior notice.
English
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