Hitachi NR 90AD (S) Manual

TECHNICAL DATA
AND
SERVICE MANUAL
STRIP NAILER
NR 90AD
SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT
LIST No. E016 Jun. 2004
N
MODEL
NR 90AD
Hitachi 
Power Tools

REMARK:
Throughout this TECHNICAL DATA AND SERVICE MANUAL, a symbol(s)
is(are) used in the place of company name(s) and model name(s) of our
competitor(s). The symbol(s) utilized here is(are) as follows:
Symbols Utilized Competitors
Company Name Model Name
PPaslode F-350S
QSENCO FramePro 701XP

CONTENTS
Page
1. PRODUCT NAME............................................................................................................................. 1
2. MARKETING OBJECTIVE ............................................................................................................... 1
3. APPLICATIONS................................................................................................................................ 1
4. SELLING POINTS ............................................................................................................................ 1
5. SPECIFICATIONS ............................................................................................................................ 2
5-1. Specifications.....................................................................................................................................2
5-2. Explanation of the Nailing Action .......................................................................................................3
5-3. Nail Selection.....................................................................................................................................4
5-4. Nail Driving Force ..............................................................................................................................5
6. COMPARISONS WITH SIMILAR PRODUCTS ................................................................................ 6
7. PRECAUTIONS IN SALES PROMOTION ....................................................................................... 7
7-1. Handling Instructions .........................................................................................................................7
7-2. Warning Label....................................................................................................................................7
7-3. Related Laws and Regulations ..........................................................................................................8
8. MECHANISM AND OPERATION PRINCIPLE ................................................................................. 9
8-1. Mechanism ........................................................................................................................................9
8-2. Operation Principle ..........................................................................................................................11
9. TROUBLESHOOTING GUIDE ....................................................................................................... 14
9-1. Troubleshooting and Correction.......................................................................................................14
9-2. Regrinding the Driver Blade.............................................................................................................17
9-3. Possible Causes and Correction of Air Leakage .............................................................................18
10. DISASSEMBLY AND REASSEMBLY .......................................................................................... 20
10-1. General Precautions in Disassembly and Reassembly .................................................................20
10-2. Disassembly and Reassembly of the Output Section....................................................................21
10-3. Disassembly and Reassembly of the Control Valve Section .........................................................24
10-4. Disassembly and Reassembly of the Driving Section ...................................................................27
10-5. Disassembly and Reassembly of the Cap and the Magazine Section ..........................................30
11. INSPECTION AND CONFIRMATION AFTER REASSEMBLY .................................................... 33
12. STANDARD REPAIR TIME (UNIT) SCHEDULES ....................................................................... 34
Assembly Diagram for NR 90AD

--- 1 ---
1. PRODUCT NAME
Hitachi 90 mm (3-1/2") Strip Nailer, Model NR 90AD
2. MARKETING OBJECTIVE
The Model NR 90AD is a framing nailer for clipped head (D-head) nails. This is developed as a next-generation
nailer with an all-new design in order to expand our market share. The main features of the Model NR 90AD are
as follows:
(1) Lightweight (3.2 kg) and good balance
(2) Low height
(3) Rapid driving and quick response mechanism
(4) New aggressive appearance
(5) Selective actuation (single actuation/contact actuation)
(6) Tool-less depth adjustment
(7) Comfortable grip
3. APPLICATIONS
Floor and framing
Truss build-up, window build-up
Subflooring and roof decking
Wall sheathing
Mobile home and modular housing construction
4. SELLING POINTS
With "single actuation/
contact actuation" selector
New aggressive appearance
Low height
Rapid driving and
quick response
Tool-less depth
adjustment
Comfortable grip
Lightweight, only 3.2 kg (7.0 lbs.) and good balance

--- 2 ---
Optional accessories
Nail capacity
3.2 kg (7.0 lbs.)
2.5 ltr/cycle at 7 kgf/cm2(0.088 ft3/cycle at 100 psi) (2.5 ltr/cycle at 6.9 bar)
Corrugated cardboard box
3 pcs./sec.
Driving speed
462 mm x 322 mm x 125 mm
(18-3/16" x 12-11/16" x 4-15/16")
86 nails
Dimensions
(Length x Height x Width)
Nail feed system
3/8 NPT thread
Standard accessories
Weight
Spiral spring
Air consumption
Air inlet
Package dimensions
(Length x Height x Width)
Packaging
587 mm x 398 mm x 136 mm
(23-1/8" x 15-21/32" x 5-11/32")
Safety glasses (Code No. 875769)............................................................ 1
Pneumatic tool lubricant (1 oz oil feeder) (Code No. 877153)
Pneumatic tool lubricant (4 oz oil feeder) (Code No. 874042)
Pneumatic tool lubricant (1 quart can) (Code No. 876212)
Grease (ATTOLUB No. 2) (500 g (1.1 lbs.)) (Code No. 317918)
5. SPECIFICATIONS
5-1. Specifications
Reciprocating piston type
Model
Driving system
NR 90AD
Operating pressure 5 --- 8.5 kgf/cm2 (70 --- 120 psi, 4.9 --- 8.3 bar) (Gauge pressure)

--- 3 ---
5-2. Explanation of the Nailing Action
To meet the requirements of "ANSI SNT-101-2002", the Model NR 90AD is equipped with a nailing operation
switching device at the valve portion as shown in the figures below. Use SINGLE ACTUATION MECHANISM
(SINGLE SEQUENTIALACTUATION MECHANISM) or CONTACT ACTUATION MECHANISM in accordance with
the work to be performed. Each nailing operation is as follows.
SINGLE ACTUATION MECHANISM (SINGLE SEQUENTIALACTUATION MECHANISM):
First, press the pushing lever against the wood; next, pull the trigger to drive the nail. First, pull the trigger;
next, press the pushing lever against the wood to drive the nail. After nailing once, nailing will not be possible
again until the trigger is released and pressed again.
CONTACT ACTUATION MECHANISM:
First, press the pushing lever against the wood; next, pull the trigger to drive the nail. First, pull the trigger;
next, press the pushing lever against the wood to drive the nail. If the trigger is held back, a nail will be driven
each time the pushing lever is pressed against the wood.
Nailing operation switching device
Switching device
(Change knob) Switching device
(Change knob)
SINGLE ACTUATION
MECHANISM
(Switching device:
upward position)
CONTACT ACTUATION
MECHANISM
(Switching device:
downward position)

--- 4 ---
5-3. Nail Selection
The Model NR 90AD utilizes D-head (clipped head) nails collated with paper tape.
Applicable nail dimensions are shown below. Please note that screw-type nails cannot be used with the Model
NR 90AD.
CAUTION: Ensure that nails are as specified in Fig. 1. The Model NR 90AD utilizes D-head (clipped
head) nails collated at an angle of 35 degrees which are the same as the nails utilized by P.
However, some D-head nails made by other makers are collated at a different angle of 26
degrees. Use of such nails will cause clogging of nails and subsequent damage to the
nailer. Also avoid use of misaligned nails or nails collated with a weak paper tape. Do not
use P's 2" Roundrive nail (eccentric full round head nail) with the Model NR 90AD because it
may cause bending of nails. It is recommended to use genuine HITACHI nails to ensure
satisfactory driving quality.
6.8 mm
(0.266")
2.9 mm
(0.113")
50 mm (2")
Minimum
Paper tape collated strip nails D-head (clipped head) nails
Fig. 1 Dimensions of nail
Maximum
7.7 mm
(0.303")
90 mm (3-1/2")
3.8 mm
(0.148")
35˚
Paper tape
3.8 mm x 90 mm nails
(0.148" x 3-1/2")
Max.
4.6 mm
(0.181")
Max.
31.7 mm
(1.248")

--- 5 ---
5-4. Nail Driving Force
Figure 2 shows by type of wood and nail, the nailer output energy provided by the supply pressure and the nailing
energy required for driving the nail flush. Air pressure which exceeds the intersecting point between the nailer
output energy and the nailing energy required for driving the nail allows the nail to be fully driven.
For example, when driving a nail of 3.3 mm dia. by 90 mm length (0.131" x 3-1/2") into nine sheets of 12 mm
plywood (108 mm thick ) with the Model NR 90AD, a pressure of about 6.8 bar (6.9 kgf/cm2, 99 psi) allows the
nailer to drive the nail flush with the wood surface. Apressure beyond this value causes the nail head to be driven
below the wood surface. Fig. 2 should be used as reference data because those values vary depending on the
type, moisture content, and grain of wood.
Fig. 2 Required nailing energy and nailer output energy
NR 90AD
NR 83AA3, P, Q
12 mm (0.47")
plywood x 9
Required nailing energy Nailer output energy

--- 6 ---
6. COMPARISONS WITH SIMILAR PRODUCTS
2.9 mm --- 3.3 mm
(0.113" --- 0.131")
Maker HITACHI
Air consumption at
7 kgf/cm2(100 psi)
Operating pressure
Magazine type
Weight
Dimensions
(L x H x W)
Model
Nail capacity
(3-1/4" x 0.131)
5 --- 8.5 kgf/cm2
(70 --- 120 psi)
462 mm x 322 mm x 125 mm
(18-3/16" x 12-11/16" x 4-15/16")
NR 90AD
2.5 ltr/cycle
(0.08 ft3/cycle)
86
Rear loading (Aluminum)
3.2 kg (7.0 lbs.)
5 --- 8.5 kgf/cm2
(70 --- 120 psi)
460 mm x 360 mm x 108 mm
(18-1/8" x 14-3/16" x 4-1/4")
NR 83AA3
2.1 ltr/cycle
(0.073 ft3/cycle)
86
Rear loading (Aluminum)
3.9 kg (8.7 lbs.)
5.6 --- 8.5 kgf/cm2
(80 --- 120 psi)
488 mm x 333 mm x 130 mm
(19-7/32" x 13-1/8" x 5-1/8")
2.0 ltr/cycle
(0.07 ft3/cycle)
89
Top loading (Aluminum)
3.7 kg (8.2 lbs.)
With wrench
P
Driving depth
adjustment mechanism Tool not required Not provided With wrench
Protection of free-fire Not provided Not provided Provided Direction change of
exhaust air
Handing grip
Applicable
nails
(Clip head) Length
Dia.
Not provided
Rubber
50 mm --- 90 mm
(2" --- 3-1/2")
2.9 mm --- 3.8 mm
(0.113" --- 0.148")
Not provided
Rubber
50 mm --- 83 mm
(2" --- 3-1/4")
Rubber
50 mm --- 90 mm
(2" --- 3-1/2")
2.9 mm --- 3.8 mm
(0.113" --- 0.148")
Tool not required
5 --- 7 kgf/cm2
(70 --- 100 psi)
380 mm x 333 mm x 107 mm
(14-31/32" x 13-1/8" x 4-1/4")
2.6 ltr/cycle
(0.091 ft3/cycle)
64
Rear loading (Aluminum)
3.8 kg (8.4 lbs.)
Tool not required
Q
Provided
Rubber
50 mm --- 90 mm
(2" --- 3-1/2")
2.9 mm --- 3.8 mm
(0.113" --- 0.148")
Not provided
Single actuation/
contact actuation
selector
Provided Not provided Not provided

--- 7 ---
7. PRECAUTIONS IN SALES PROMOTION
In the interest of promoting the safest and most efficient use of the Model NR 90AD Nailer by all of our customers,
it is very important that at the time of sale the salesperson carefully ensures that the buyer seriously recognizes
the importance of the contents of the Handling Instructions, and fully understands the meaning of the precautions
listed on the Warning Label attached to each tool.
7-1. Handling Instructions
Although every effort is made in each step of design, manufacture, and inspection to provide protection against
safety hazards, the dangers inherent in the use of any pneumatic tool cannot be completely eliminated.
Accordingly, general precautions and suggestions for use of pneumatic tools, and specific precautions and
suggestions for the use of the pneumatic nailer are listed in the Handling Instructions to enhance the safe, efficient
use of the tool by the customer.
Salespersons must be thoroughly familiar with the contents of the Handling Instructions to be able to offer
appropriate guidance to the customers during sales promotion.
7-2. Warning Label
Each Model NR 90AD unit is provided with a Warning Label (illustrated below) which lists basic safety precautions
in its use. Carefully ensure that customers fully understand and follow these precautions before using the tool.

--- 8 ---
7-3. Related Laws and Regulations
As nailers and staplers are designed to instantaneously drive nails and staples, there is an ever-present danger of
misfiring and subsequent possible serious injury. Accordingly, close attention in handling is absolutely necessary
at all times. Carefully ensure that the customer is fully aware of the precautions listed in the Handling Instructions
provided with each unit.
While there are no specific safety regulations, there are related items in various general safety regulations with
which the salespersons should be familiar in order to properly advise the customer. Please check your national
and/or local regulations for applicable items. Some applicable items are outlined below.
The U.S.A:
OSHA 1926.102 Eye and face protection
1926.302 Power-operated hand tools
ANSI SNT-101-2002 Portable, Compressed-Air-Actuated,
Fastener Driving Tools-Safety Requirements for

--- 9 ---
8. MECHANISM AND OPERATION PRINCIPLE
8-1. Mechanism
As illustrated in Fig. 3, the Model NR 90AD can be generally divided into four sections:
Output section, control valve section, driving section and magazine section.
Although the basic construction of the Model NR 90AD is the same as that of the Model NR 90AC3, most of the
parts of the above sections have been newly designed for maximum performance in a strip nailer. Features of the
main parts are described below.
Output section .............. Most of the parts have been newly designed.
(1) The body and exhaust cover are made of aluminum to achieve simplification and
light weight.
(2) The head guard made of stainless steel is mounted to the head.
Control valve section .... Most of the parts have been newly designed.
(1) All the parts except the plunger are made of resin to achieve the light weight.
(2) The entire control valve section is made into a unit type for easy assembly.
(3) The single actuation (single sequential actuation)/contact actuation mechanisms are
the same as that of the Model NR 90AC3.
Driving section .............. Most of the parts have been newly designed.
(1) The basic structure of the depth adjustment mechanism is the same as that of the
Model NV 75AG.
Magazine section ......... Most of the parts have been newly designed.
(1) The magazine is the same rear loading type as the Model NR 83AA3. It is uniquely
shaped and made of aluminum to achieve the light weight.
(2) The magazine cover is integral with the anti-backing ratchet to achieve the light
weight.

--- 10 ---
Fig. 3 Construction
Cylinder [15]
Piston [13]
(Driver blade)
Body Ass'y [24]
Exhaust Cover [5]
Cap [41]
Driving section Output section
Head Valve [9]
Exhaust Valve
Rubber [11]
Accumulator
Piston Bumper [31]
Nose [29]
Pushing Lever (A) [35]
Control valve section
Plunger Spring [68]
Plunger [70]
Valve Piston [66]
Valve Bushing (B) [63]
Valve Bushing (A) [71]
Control valve section
Switching device
(Change Knob (C) [46])
Trigger (C) [50]
Head Guard [2]
Magazine section

--- 11 ---
8-2. Operation Principle
(1) Before nailing (See Fig. 4 and Fig. 5.)
1) When compressed air is fed to the main body, it
fills the accumulator ( portion).
2) At the same time, the compressed air flows into
the valve piston lower chamber of the control valve
section and forces the Valve Piston [66] upward.
Compressed air is then fed through the air supply
vent and air passage to the head valve chamber.
As a result, the Head Valve Spring [7] is pushed
down to seal the Head Valve [9] and Cylinder [15].
(2) When nailing (See Fig. 4 and Fig. 5.)
1) When Pushing Lever (A) [35] and Trigger (C) [50]
are operated together and the Plunger [70] is
pushed upward, the compressed air in the valve
piston lower chamber is discharged from the
bottom of the Plunger [70]. As a result, the
compressed air in the accumulator ( portion)
pushes down Valve Piston [66], blocking the air
supply vent and opening the exhaust valve.
2) When the exhaust valve opens, the compressed
air in the head valve chamber is discharged into
the atmosphere through the air passage.
3) When the air pressure on the bottom surface of the
Head Valve [9] overcomes the strength of the
Head Valve Spring [7], the Head Valve [9] is
pushed upward. At this time, the Head Valve [9]
seals with the Exhaust Valve Rubber [11], blocking
the passage to the exhaust vent.
4) When the Head Valve [9] goes up, the
compressed air in the accumulator flows rapidly
into the Cylinder [15], forcing the Piston [13]
downward to strike the nail. When the Piston [13]
passes the cylinder hole, the compressed air flows
into the return air chamber and is accumulated
there.
Fig. 5 Control valve section
Fig. 4
Head valve chamber
Nail
Air passage
Control
valve
section
Cylinder hole
Head Valve
Spring [7]
Exhaust Valve Rubber [11]
Head Valve [9]
Cylinder [15]
Return air chamber
Pushing Lever (A) [35]
Piston [13]
Accumulator
Trigger (C) [50]
To the head valve chamber
Plunger [70]
Valve Piston [66]
Valve piston lower chamber
Exhaust
valve
Air passage
Accumulator
Air supply vent

--- 12 ---
(3) During return (See Fig. 6 and Fig. 7.)
1) When either Pushing Lever (A) [35] or Trigger (C)
[50] is released, the Plunger [70] goes down and
the compressed air in the accumulator flows into
the valve piston lower chamber.
2) As the air pressure in the valve piston lower
chamber increases to overcome the air pressure
applied on the upper portion of the Valve Piston
[66], the Valve Piston [66] is forced upward. When
this occurs, the exhaust valve is closed and the air
supply vent is opened.
3) When the air supply vent opens, the compressed
air in the accumulator ( portion) passes
through the air passage and flows into the head
valve chamber to push down the Head Valve [9].
As a result, the Head Valve [9] and the Cylinder
[15] are sealed and, at the same time, the Head
Valve [9] and the Exhaust Valve Rubber [11]
separate to open the exhaust vent.
4) The compressed air above the Piston [13] is
discharged into the atmosphere through the
exhaust vent. In this way, the air pressure above
the Piston [13] is reduced, and the greater
pressure of the air accumulated in the return air
chamber pushes the Piston [13] upward.
5) If the air pressure below the Piston [13] is higher
than that of the atmosphere after the Piston [13]
has fully returned, the excess air pressure is
discharged into the atmosphere through the
clearance between Piston Bumper [31] and the
driver blade. Fig. 7 Control valve section
Fig. 6
Head valve chamber
Air passage
Control
valve
section
Piston Bumper [31]
Head Valve [9]
Exhaust vent Exhaust Valve Rubber [11]
Return air
chamber
Driver blade
Pushing Lever (A) [35]
Piston [13]
Accumulator
Trigger (C) [50]
To the head valve chamber
Plunger [70]
Valve Piston [66]
Valve piston lower chamber
Exhaust
valve
Air passage
AccumulatorAir supply vent
Cylinder [15]
Head Valve
Spring [7]

--- 13 ---
(4) Single actuation mechanism/contact actuation mechanism: (Fig. 8 and Fig. 9)
Single/contact actuation mechanism changeover is accomplished by turning the switching device
(Change Knob (C) [46]).
Single actuation mechanism (Switching device:
upward position):
1) Immediately after driving the first nail, the
control valve should be as shown in Fig. 7.
2) When only Pushing Lever (C) [53] is released
and Trigger (C) [50] is held as shown in Fig. 8,
the plate of Trigger (C) [50] contacts Change
Knob (C) [46] and the Plunger [70] returns
(lowers) only halfway.
Because of this, compressed air does not flow
into the valve piston lower chamber, and Valve
Piston [66] remains in the lowered position.
Accordingly, the Piston [13] remains in the
lowered position as shown in Fig. 6.
3) When Trigger (C) [50] is released, the Plunger
[70] returns (lowers) completely as shown in
Fig. 5. Compressed air then flows into the valve
piston lower chamber, and the Valve Piston [66]
is forced upward. The Piston [13] then returns
fully upward. Therefore, unless Trigger (C) [50]
is released after each nailing operation, the
structural mechanism prevents the next nailing
operation.
Contact actuation mechanism (Switching device:
downward position):
1) Immediately after the first nail is driven, the
control valve should be as shown in Fig. 7.
2) Even when only Pushing Lever (C) [53] is
released and Trigger (C) [50] is held, the
Plunger [70] returns (lowers) completely as
shown in Fig. 9. Thus the Piston [13] returns
(raises) fully. Accordingly, continuous nailing
can be accomplished by pushing only Pushing
Lever (C) [53] up and down while holding
Trigger (C) [50] depressed.
Plunger [70]
Pushing Lever (C) [53]
Valve piston
lower chamber
Trigger (C) [50]
Valve Piston [66]
Accumulator
Switching device (Change Knob (C) [46])
(Upward position)
Fig. 8 Single actuation mechanism
Plunger [70]
Pushing Lever (C) [53]
Valve piston
lower chamber
Trigger (C) [50]
Valve Piston [66]
Accumulator
Switching device (Change Knob (C) [46])
(Downward position)
Fig. 9 Contact actuation mechanism

--- 14 ---
<Magazine>
Magazine is abnormal
(deformed or damaged).
Nail feeder is abnormal
(deformed or damaged).
Ribbon spring is abnormal
(deformed or damaged).
Nail rail is abnormal
(deformed, burrs, damaged
or fatigued).
Adhesive fragments are on
the nail rail or they need oil.
Foreign matter is found on
the guide face of the nail
feeder.
<Nails>
Magazine is not loaded with
specified genuine nails.
Problem Possible cause Inspection method Remedy
9. TROUBLESHOOTING GUIDE
9-1. Troubleshooting and Correction
1) Nails cannot
be driven. Check if the magazine is
normally loaded with
specified nails.
Check if nails (one strip) are
fed smoothly into the nail
injection port of the nose.
Use specified nails.
Magazine is loaded with
abnormal nails (bent nails,
large or small round-head
nails, abnormal collation,
etc.).
Nail or collating band clogs.
Collating band is deformed
or torn.
Remove the abnormal nails
and load the magazine with
normal nails.
<Nose>
Nail inlet groove of the nose
is abnormal (deformed,
burrs or damaged).
Adhesive fragments are in
the nail inlet groove.
Repair or replace the
defective part.
Remove the adhesive
fragments and apply oil to
the nail feeder, ribbon spring
and the nail rail.
Repair or replace the
defective part.
Remove the adhesive
fragments.
Check if the nail feeder
operates smoothly in the
magazine.
Check if nails (one strip)
move smoothly in the
magazine.

--- 15 ---
Plunger, valve piston, valve
bushing (A) or valve bushing
(B) is abnormal (galled or
damaged).
O-ring is worn or oiling is
needed.
Air pressure is too low.
Piston O-ring is worn or
damaged.
Piston bumper is abnormal
(dislocated, deformed or
damaged).
O-ring of the cylinder is
abnormal (dislocated,
deformed or damaged).
Driver blade is abnormal
(deformed, burrs, damaged
or fatigued).
Cylinder's internal surface is
abnormal (deposits of dirt or
worn).
Head valve sliding surface is
abnormal (galled, damaged
or needs oil).
Head valve spring is
abnormal (fatigued or
damaged).
Problem Possible cause Inspection method Remedy
Pull the nail feeder
backward and perform idle
driving. Check if the driver
blade has returned.
Check if nails can be driven
at 5 kgf/cm2.
While operating the nailer
without nails, check if the
drivng operation is
performed.
After operating the nailer
without nails, check if the
driver blade is kept in the
down position.
After making idle driving,
check if the driver blade is
kept in the down position.
Disassemble the control
valve and check the O-ring.
Adjust for 5 to 8.5 kgf/cm2.
Replace the piston O-ring.
Replace the piston bumper.
Reassemble or replace.
Repair or replace.
Remove the dirt and apply
oil, or replace.
Replace the defective part.
Apply grease.
Replace the head valve
spring.
Replace the defective part.
Apply grease, or replace.
<Output section>
<Control valve section>
For short nails, the adjuster
is raised too high.
Nails are not fully fed into
the injection port.
Unspecified nails are used.
Driver blade is worn.
Workpiece is very hard.
Nail feeder (A) is abnormal
(worn or damaged).
2) Nails are bent
when being
driven.
Check if the adjuster is
raised too high.
See item 1).
Check if the driver blade tip
is abnormally worn.
Drive a nail into soft wood
workpiece and check if the
nail is bent.
Check nail feeder (A) for
abnormal condition.
Turn the adjuster to the
lower position to decrease
the pressure.
See item 1).
Replace the driver blade.
Do not use unspecified
workpieces.
Replace nail feeder (A).

--- 16 ---
Check if the driver blade tip
is worn.
Check nail feeder (A) for
abnormal condition.
Perform idle driving or
actually drive with nails, and
check if the driver blade has
returned completely.
O-ring in plunger is worn.
O-ring in valve piston is
worn.
Abnormal plunger sliding
surface of valve piston
(seized or deformed).
Abnormal plunger, trigger
arm (C), pushing lever (C)
and/or body (worn or
damaged).
The position of a switching
device is mistaken.
5) Single
actuation
mechanism is
not possible.
Disassemble the control
valve section, and check the
O-ring of the plunger and
the valve piston.
Check each part for
abnormalities (worn,
damaged, deformed, etc.).
The position of a switching
device is checked.
Replace the part.
Replace the part.
Replace the part.
Replace the abnormal part.
A switching device is set to
the correct position.
Problem Possible cause Inspection method Remedy
Adjust the adjuster to the
proper position.
Adjust for 5 to 8.5 kgf/cm2.
Do not use unspecified
workpieces.
Replace the driver blade.
Replace the defective part.
Adjuster is improperly
adjusted.
Air pressure is too low.
Workpiece is very hard.
Driver blade is worn.
Piston O-ring is abnormal
(worn or damaged).
Cylinder's internal surface is
abnormal (worn or rough).
3) Head of a nail
driven into a
workpiece
protrudes
from the wood
surface.
Turn the adjuster to the
lowest position and drive a
nail.
Drive a nail into soft wood
workpiece and check if the
head protrudes from the
wood surface.
Operate the nailer without
nails and check if the driver
blade is projected from the
nose tip.
Disassemble the output
section and check the
piston O-ring and the inner/
outer surfaces of the
cylinder for abnormal
condition.
See <Magazine> in item 1).
Driver blade worn.
Nail feeder (A) is abnormal
(worn or damaged).
Check if they move
smoothly after putting nails,
and check if the nail feeder
operates smoothly.
See <Magazine> in item 1).
Replace the part.
Replace nail feeder (A).
See <Output section> in
item 1).
<Improper nail feed>
Unspecified nails used. Check if the nails are
specified ones. Use specified nails.
4) Nails clog the
mechanism.
See <Output section> in
item 1).
<The driver blade has not
returned completely.>

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9-2. Regrinding the Driver Blade
The tip of the driver blade should be ground as shown in Fig. 10. To grind with a grinder, gradually grind the tip
while cooling the ground area with water to prevent it from being excessively heated. Excessive grinding will
rapidly reduce the service life of the driver blade. In such a case, replace the driver blade.
Fig. 10
Concave
Grinding surface
Driver blade
5˚