Hitachi NR 90AC3 Manual

TECHNICAL DATA
AND
SERVICE MANUAL
STRIP NAILER
NR 90AC3
SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT
LIST No. E013 Sep. 2003
N
MODEL
NR 90AC3
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
P SENCO SN65C
Q Paslode F-350SRH

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 ...............................................................................................................................4
5-5. Optional Accessories ..........................................................................................................................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. Interchangeability..............................................................................................................................10
8-3. Operation Principle ...........................................................................................................................12
9. TROUBLESHOOTING GUIDE ........................................................................................................15
9-1. Troubleshooting and Correction........................................................................................................15
9-2. 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 ..........................................................23
10-4. Disassembly and Reassembly of the Driving Section ....................................................................26
10-5. Disassembly and Reassembly of the Cap and the Magazine Section ...........................................27
11. INSPECTION AND CONFIRMATION AFTER REASSEMBLY ..................................................... 30
12. STANDARD REPAIR TIME (UNIT) SCHEDULES ........................................................................ 31
Assembly Diagram for NR 90AC3

--- 1 ---
1. PRODUCT NAME
Hitachi 90 mm (3-1/2") Strip Nailer, Model NR 90AC3
2. MARKETING OBJECTIVE
The new Model NR 90AC3 strip nailer is a minor-changed version of the current Model NR 90AC2. Owing to the
modification of the ANSI standard, the current Model NR 90AC2 has gone out of production since the 1st of May
2003. To correspond to this, the switching device (change knob) was added to select the nailer operation
between "single actuation (single sequential actuation)" and "contact actuation" (the current Model NR 90AC2 is
provided with the contact actuation mechanism only).
Except the above, the construction is common to the current Model NR 90AC2 as well as the features such as
driving response and balance.
3. APPLICATIONS
Floor and wall 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

--- 2 ---
Optional accessories
Nail capacity
4.0 kg (8.9 lbs.)
2.7 ltr/cycle at 7 kgf/cm2(0.095 ft3/cycle at 100 psi) (2.7 ltr/cycle at 6.9 bar)
Corrugated cardboard box
3 pcs./sec.
Driving speed
503 mm x 353 mm x 121 mm
(19-13/16" x 13-7/8" x 4-3/4")
50 to 60 nails (2 strips)
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")
Nose cap (Code No. 881968)................................................................... 1
Hex. bar wrench for M5 screw (Code No. 944458) .................................... 1
Hex. bar wrench for M6 screw (Code No. 944459) .................................... 1
Hex. bar wrench for M8 screw (Code No. 872422) .................................... 1
Safety glasses (Code No. 875769)............................................................ 1
Full sequential actuation mechanism kit (Code No. 884142)
(Sequential trip mechanism kit)
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)
Case (Code No. 878898)
5. SPECIFICATIONS
5-1. Specifications
Reciprocating piston type
Model
Driving system
NR 90AC3
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 90AC3 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. A FULL SEQUENTIALACTUATION MECHANISM KIT (SEQUENTIAL TRIP
MECHANISM KIT) is also available as an option. 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.
FULL SEQUENTIALACTUATION MECHANISM:
First, press the pushing lever against the wood; next, pull the trigger to drive the nail. Follow the same
sequence to continue driving nails.

--- 4 ---
7 mm
(0.286")
60 mm (2-3/8")
Minimum
Plastic-collated strip nails full-head nails
Maximum
8.3 mm
(0.327")
90 mm (3-1/2")
4.1 mm
(0.162")
20 deg. Min. 13 mm
(0.5") Max. 41 mm
(1.6")
5-3. Nail Selection
The Model NR 90AC3 utilizes round-head nails collated with plastic resin into bands of 25 to 30 pieces.
Applicable nail dimensions are shown below.
CAUTION: Ensure that nails are as specified in Fig. 1. Other nails will cause clogging of nails and
subsequent damage to the nailer.
Fig. 1 Dimensions of nails
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 required nailing energy for driving the nail allows the nail to be fully driven.
For example, when driving a nail of 4.1 mm dia. by 90 mm length (0.162" x 3-1/2") into a workpiece of hemlock
spruce with the Model NR 90AC3, a pressure of about 6.4 bar (6.5 kgf/cm2, 92 psi) allows the nailer to drive the
nail flush to the wood surface. A pressure beyond this value causes the nail head to be driven below the wood
surface. Figure 2 should be used as reference data because those values vary depending on the type, moisture
content, and grain of wood.
2.9 mm
(0.113")

--- 5 ---
Fig. 2 Required nailing energy and nailer output energy
5-5. Optional Accessories
Full sequential actuation mechanism kit (Sequential trip mechanism kit) (Code No. 884142)
Full sequential actuation mechanism kit (Sequential trip mechanism kit) is provided as an optional accessory for
the Model NR 90AC3. By using this optional accessory, a nail is driven by pressing the pushing lever first against
a workpiece and then pulling the trigger, and no nail is driven when pulling the trigger first and then pressing the
pushing lever against a workpiece (single actuation). Please recommend the sequential fire parts set to the
customers who want to use it. Salespersons must instruct the customers to read the Handling Instructions
attached to the sequential fire parts set and also the Handling Instructions of the Model NR 90AC3 thoroughly for
correct use.
Hemlock spruce
NR 90AC2
NR 90AC3
P
Q
Air pressure setting to drive nail flush
with NR 90AC3

--- 6 ---
2.9 --4.1 mm
(0.113" --0.162")
6. COMPARISONS WITH SIMILAR PRODUCTS
Maker HITACHI
Air consumption at
7 kgf/cm2(100 psi)
Operating pressure
Magazine type
Weight
Dimensions
(L x H x W)
Model
Nail capacity
(3-1/2 x .162")
5 -- 8.5 kgf/cm2
(70 --120 psi)
503 x 353 x 121 mm
(19-13/16 x 13-7/8 x 4-3/4")
NR 90AC3
2.7 ltr/cycle
(.095 ft3/cycle)
50
Rear loading
(Aluminum)
4.0 kg (8.9 lbs.)
5 -- 8.5 kgf/cm2
(70 --120 psi)
548 x 353 x 121 mm
(21-9/16 x 13-7/8 x 4-3/4")
NR 90AC2
2.7 ltr/cycle
(.095 ft3/cycle)
50
Rear loading
(Aluminum)
4.3 kg (9.5 lbs.)
5 -- 8.5 kgf/cm2
(70 --120 psi)
501 x 343 x 111 mm
(19-3/4 x 13-5/8 x 4-3/8")
2.3 ltr/cycle
(.081 ft3/cycle)
50
Rear loading
(Aluminum)
3.7 kg (8.2 lbs.)
With wrench
P
Driving depth
adjustment mechanism
Tool not required Tool not required With wrench
Idling protector Provided Provided Provided
Direction change
of exhaust air
Handle grip
Applicable
nails Length
Dia.
Tool not required
Rubber
60 -- 90 mm
(2-3/8" -- 3-1/2")
2.9 -- 4.1 mm
(0.113" -- 0.162")
Tool not required
Rubber
60 -- 90 mm
(2-3/8" -- 3-1/2")
Leather
60 -- 90 mm
(2-3/8" -- 3-1/2")
2.9 -- 4.1 mm
(0.113" -- 0.162")
With wrench
5.6 -- 8.5 kgf/cm2
(80 ---120 psi)
569 x 332 x 130 mm
(22-13/32 x 13-1/16 x 5-1/ 8")
2.4 ltr/cycle
(.085 ft3/cycle)
50
Top loading
(Aluminum)
3.9 kg (8.6 lbs.)
With wrench
Q
Not provided
Rubber
50 -- 90 mm
(2" -- 3-1/2")
2.9 -- 4.1 mm
(0.113" -- 0.162")
Note:
The Model NR 90AC3 is equipped with a pushing lever stopper as an idling protector. The Pushing Lever Stopper
[74] is placed over Pushing Lever (B) [33] to prevent Pushing Lever (B) [33] from being pushed up when no nail
is loaded in the magazine or the number of nails remained in the magazine is five or less (depending on the types
of nails). (See Fig. 3.)
Fig. 3
5
Pushing lever (B) [33]
Pushing Lever Stopper [74]
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 90AC3 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.
The Model NR 90AC3 Nailer is designed for continuous nail driving (however, some of the Model NR 90AC3 are
designed for single-shot operation only for some destinations). At time of sale, the salesperson must inform the
customer that the sequential trip mechanism kit which can change the Model NR 90AC3 to a single-shot nailer is
optionally available, and recommend it to the customers who want to use it. Refer to the leaflet attached together
with the Instruction Manual for details.
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 90AC3 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 90AC3 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 90AC3 is the same as that of the Model NR 90AC2 and
interchangeable components are used as much as possible, the Model NR 90AC3 is provided with the single
actuation (single sequential actuation)/contact actuation mechanisms in order to correspond to the modification of
the ANSI standard. The driving section and the magazine section are common to those of the Model NR 90AC2.
Primary differences from the Model NR 90AC2 are described below.
Output section .............. Body: Newly designed.
Control valve section .... Following parts were changed or added owing to the change of the construction
(selectable either the single actuation mechanism or the contact actuation mechanism).
Plunger (A): Newly designed (common to the Model NT 65MA2).
Valve piston (B): Newly designed (common to the Model NT 65MA2).
Trigger (A): Newly designed (common to the Model NT 65MA2).
Change knob (switching device): Added new parts.
Fig. 4 Construction
Exhaust vent
Adjuster (A) [34]
Cylinder [17]
Piston [19]
Piston Bumper (A)
[24]
Trigger (A)
[47]
Dust Filter [42]
Exhaust
Cover [5]
Body [22]
Cap [43]
Nail feeder ass'y
Magazine section
Driving section Output section
Top Cover [3]
Exhaust Valve
Rubber [7]
Head Valve [10]
Accumulator
Piston Bumper (B)
[25]
Nose [30]
Pushing Lever (B)
[33]
Pushing Lever (A)
[37]
Control valve section
Plunger Spring [60]
Plunger (A) [61]
Valve Piston (B) [57]
Valve Bushing
(B) [54]
Valve Bushing
(A) [63]
Control valve section
Switching device
(Change Knob [50])

--- 10 ---
8.2 Interchangeability
Interchangeability of the parts between the Model NR 90AC3 and the Model NR 90AC2 is described below.
As described in 8-1, the driving section and the magazine section are identical with those of the Model NR
90AC2 and all the parts of the driving section and the magazine section are interchangeable with those of the
Model NR 90AC2. The parts that are newly designed, changed, or added for the Model NR 90AC3 and not
interchangeable with those of the Model NR 90AC2 are described in detail.
(1) Output section
Body [22]
Part NR 90AC3 NR 90AC2
7.6 mm (.299")
dia. hole
Common to the Model NT 65MA2.
7 mm (.276")
dia. hole
Trigger (A) [47]
Part NR 90AC3 NR 90AC2
7.6 mm (.299") dia. hole
Color: Aluminum (silver)
7 mm (.276") dia. hole
Valve Piston (B) [57]
Color: Black
24
C1
7.6 12.2
12.87
324
9.5 mm (.374") dia.
Common to the Model NT 65MA2.
Be careful not to make mistakes in
mounting valve piston (B) because it is
similar to that of the Model NR 65AK and
other models but not interchangeable.
The parts of the output section except the above are common to those of the Model NR 90AC2.
(2) Control valve section
0.4

--- 11 ---
Plunger (A) [61]
Steel Ball D3.97 [48]
Change Knob [50]
Part NR 90AC3 NR 90AC2
Newly designed
Common to the Model NT 65MA2.
Be careful not to make mistakes in
mounting plunger (A) because it is similar
to that of the Model NR 65AK and other
models but not interchangeable.
Groove
(2) Control valve section (continued)
No groove
Common to the Model NT 65MA2.
Spring (C) [49] Common to the Model NT 65MA2.
12.6 34.6 34
12
The parts of the control valve section except the above are common to those of the Model NR 90AC2.

--- 12 ---
8-3. Operation Principle
(1) Before nailing (See Fig. 5 and Fig. 6.)
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 Valve Piston (B) [57] 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 [8] is pushed
down to seal the Head Valve [10] and Cylinder
[17].
(2) When nailing (See Fig. 4 and Fig. 5.)
1) When Pushing Lever (A) [37] and Trigger (A) [47]
are operated together and Plunger (A) [61] is
pushed upward, the compressed air in the valve
piston lower chamber is discharged from the
bottom of Plunger (A) [61]. As a result, the
compressed air in the accumulator ( portion)
pushes down Valve Piston (B) [57], 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 [10] overcomes the strength of the
Head Valve Spring [8], the Head Valve [10] is
pushed upward. At this time, the Head Valve [10]
seals with the Exhaust Valve Rubber [7], blocking
the passage to the exhaust vent.
4) When the Head Valve [10] goes up, the
compressed air in the accumulator flows rapidly
into the Cylinder [17], forcing the Piston [19]
downward to strike the nail. When the Piston [19]
passes the cylinder hole, the compressed air flows
into the return air chamber and is accumulated
there.
Fig. 6 Control valve section
Fig. 5
Head valve chamber
Nail
Air passage
Control
valve
section
Cylinder hole
Head Valve
Spring [8]
Exhaust vent
Exhaust Valve Rubber [7]
Head Valve [10]
Cylinder [17]
Return air
chamber
Pushing Lever (A) [37]
Piston [19]
Accumulator
Trigger (A) [47]
To the head valve chamber
Plunger (A) [61]
Valve Piston (B)
[57]
Valve piston lower chamber
Exhaust
valve
Air passage
Accumulator
Air supply vent

--- 13 ---
(3) During return (See Fig. 7 and Fig. 8.)
1) When either Pushing Lever (A) [37] or Trigger (A)
[47] is released, Plunger (A) [61] 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 Valve Piston (B)
[57], Valve Piston (B) [57] 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 [10].
As a result, the Head Valve [10] and the Cylinder
[17] are sealed and, at the same time, the Head
Valve [10] and the Exhaust Valve Rubber [7]
separate to open the exhaust vent.
4) The compressed air above the Piston [19] is
discharged into the atmosphere through the
exhaust vent. In this way, the air pressure above
the Piston [19] is reduced, and the greater
pressure of the air accumulated in the return air
chamber pushes the Piston [19] upward.
5) If the air pressure below the Piston [19] is higher
than that of the atmosphere after the Piston [19]
has fully returned, the excess air pressure is
discharged into the atmosphere through the
clearance between Piston Bumper (B) [25] and
the driver blade. Fig. 8 Control valve section
Fig. 7
Head valve chamber
Air passage
Control
valve
section
Piston Bumper
(A) [24]
Head Valve [10]
Exhaust vent
Exhaust Valve Rubber [7]
Return air
chamber
Piston Bumper
(B) [25]
Driver blade
Pushing Lever (A)
[37]
Piston [19]
Accumulator
Trigger (A) [47]
To the head valve chamber
Plunger (A) [61]
Valve
Piston (B) [57]
Valve piston
lower chamber
Exhaust
valve
Air passage
Accumulator
Air supply vent
Cylinder [17]

--- 14 ---
(4) Single actuation mechanism/contact actuation mechanism: (Fig. 9 and Fig. 10)
Single/contact actuation mechanism changeover is accomplished by turning the switching device
(Change Knob [50]).
Single actuation mechanism (Switching device:
upward position):
1) Immediately after driving the first nail, the
control valve should be as shown in Fig. 8.
2) When only Pushing Lever (B) [33] is released
and Trigger (A) [47] is held as shown in Fig. 9,
the plate of Trigger (A) [47] contacts the
Change Knob [50] and Plunger (A) [61]
returns (lowers) only halfway.
Because of this, compressed air does not flow
into the valve piston lower chamber, and
Valve Piston (B) [57] remains in the lowered
position. Accordingly, the Piston [19] remains
in the lowered position as shown in Fig. 7.
3) When Trigger (A) [47] is released, Plunger (A)
[61] returns (lowers) completely as shown in
Fig. 6. Compressed air then flows into the
valve piston lower chamber, and Valve Piston
(B) [57] is forced upward. The Piston [19]
then returns fully upward. Therefore, unless
Trigger (A) [47] 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. 8.
2) Even when only Pushing Lever (B) [33] is
released and Trigger (A) [47] is held, Plunger
(A) [61] returns (lowers) completely as shown
in Fig. 10. Thus the Piston [19] returns
(raises) fully. Accordingly, continuous nailing
can be accomplished by pushing only Pushing
Lever (B) [33] up and down while holding
Trigger (A) [47] depressed.
Plate
Plunger (A) [61]
Pushing Lever (B) [33]
Valve piston
lower chamber
Trigger (A) [47]
Valve Piston (B) [57]
Accumulator
Switching device (Change Knob [50])
(Upward position)
Fig. 9 Single actuation mechanism
Plunger (A) [61]
Pushing Lever (B) [33]
Valve piston
lower chamber
Trigger (A) [47]
Valve Piston (B) [57]
Accumulator
Switching device (Change Knob [50])
(Downward position)
Fig. 10 Contact actuation mechanism

--- 15 ---
<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.

--- 16 ---
Plunger (A), valve piston (B),
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 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>

--- 17 ---
Problem Possible cause Inspection method Remedy
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.
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.
Turn the adjuster to the
lower position to decrease
the pressure.
See item 1).
Replace the driver blade.
Do not use unspecified
workpieces.
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 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 ring, O-ring and the
inner/outer surfaces of the
cylinder for abnormal
condition.
O-ring in plunger (A) is
worn.
O-ring in valve piston (B) is
worn.
Abnormal plunger (A) sliding
surface of valve piston (B).
(seized or deformed)
Abnormal plunger (A),
trigger arm (A), pushing
lever (B) and/or body (worn
or damaged).
The position of a switching
device is mistaken.
4) Single
actuation
mechanism is
not possible.
Disassemble the control
valve section, and check the
O-ring of plunger (A) and
valve piston (B).
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.