Hitachi NV 90HMC Manual

The new Model NV 90HMC is a high-pressure type [3-1/2" (90 mm)] of coil nailer. High-pressure nailer series
products have already been introduced to the Japanese market and become popular nationwide. This new
product offers higher punching force about three times greater than that of conventional nailers, in order to
reduce its size and weight. The new Model NV 90HMC also features strong punching force, a nose switch
mechanism, blow nozzle, dual action trigger, and a tool-less adjuster. Please expand sales of the new Model
NV 90HMC Nailer.
PRODUCT NAME
Hitachi 3-1/2” High Pressure Coil Nailer
Model NV 90HMC
• Floor and wall framing
• Truss and window built-up
• Subflooring and roof decking
• Crate and pallet construction
MARKETING OBJECTIVE
APPLICATIONS
SELLING POINTS
SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT.
LIST No.
NV 90HMC: E061
Dec. 2009
International Sales Division
N
[NEW FEATURES]
Lightweight and Compact
Powerful
Nose switch mechanism
Blow nozzle
Dual action trigger
Tool-less adjuster
Easy nail loading
Lock mechanism of trigger

REMARK:
• For more information about HANDLING INSTRUCTIONS, visit our website at:
http://www.hitachi-koki.com/manual_view_export/
• 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:
Competitors
Symbols Utilized
Company Name Model Name
PMAXHN90

CONTENTS
Page
SELLING POINTS -------------------------------------------------------------------------------------------------------------- 1
SPECIFICATIONS -------------------------------------------------------------------------------------------------------------- 3
1. Specifications------------------------------------------------------------------------------------------------------ 3
2. Nail Selection------------------------------------------------------------------------------------------------------ 4
3. Nail Punching Force --------------------------------------------------------------------------------------------- 4
4. Adjusting the Nailing Depth ------------------------------------------------------------------------------------ 6
5. Dual Action Trigger----------------------------------------------------------------------------------------------- 6
COMPARISON WITH SIMILAR PRODUCTS---------------------------------------------------------------------------- 7
1. Comparison of Specifications --------------------------------------------------------------------------------- 7
PRECAUTIONS ON SALES PROMOTION ------------------------------------------------------------------------------ 8
1. Safety Instructions ----------------------------------------------------------------------------------------------- 8
TROUBLESHOOTING GUIDE -------------------------------------------------------------------------------------------- 10
1. Troubleshooting and Repair -------------------------------------------------------------------------------- 10
2. Possible Causes and Corrections of Air Leakage------------------------------------------------------ 15
REPAIR GUIDE---------------------------------------------------------------------------------------------------------------- 18
1. Precautions on Disassembly and Reassembly --------------------------------------------------------- 18
Assembly Diagram for NV 90HMC

-1-
Lightweight and Compact
Thanks to higher punching pressure about three times greater than that of conventional nailers, both nailer
size and weight are reduced.
Powerful
Powerful punching force about 1.3 times greater than that of our conventional NV 90AH Nailer.
High pressure nailer Conventional nailer High pressure nailer
Model NV 90HMC NV 90AB P
Weight 2.5 kg (5.5 lbs.) 3.0 kg (6.6 lbs.) 2.5 kg (5.5 lbs.)
Height 322 mm (12-11/16”) 389 mm (15-5/16”) 327 mm (12-7/8”)
Punching force ratio 1.3 11.1
Nose switch mechanism
Capable of changing outlet sizes (“Small” and “Large”) according to nail head sizes for using various kinds
of nails. (Select a nose according to the head size of nails you use.)
Outlet size ”Small” Outlet size ”Large”
Nail head
diameter
ø 6.0 to ø 7.5 mm
(0.236” to 0.295”)
ø 7.5 to ø 8.6 mm
(0.295” to 0.339”)
Nose
switch
Blow nozzle
Equipped with a blow nozzle, which is very convenient in keeping the work area clean.
SELLING POINTS
Turn down the
switch lever. Turn up the
switch lever.
7.0 mm
(
0.276”
)
9.0 mm
(
0.354”
)

-2-
Dual action trigger
This function automatically switches between "Single sequential actuation mode" and "Contact actuation
mode" according to the operation sequence. This function can prevent unwanted double firing in "Single
sequential actuation mode."
Tool-less adjuster
Rotating this adjuster adjusts the nailing depth (sink quantity of the nail head).
Easy nail loading
When you open the nail magazine cover, the nail holder automatically tilts toward you so that you can easily
change nail rolls.
Lock mechanism of trigger
This lock mechanism locks the trigger so that it cannot be pulled.
Shallow
Deep
A
djuste
r

-3-
1. Specifications
Model
Item NV 90HMC
Punching system Reciprocating piston type
Operating pressure 12 to 23 kgf/cm2(170 to 320 psi, 12 to 23 bar) (Gauge pressure)
Punching speed Min. 3 pcs./sec.
Weight 2.5 kg (5.5 lbs.)
Dimensions
(Length x Height x Width)
281 mm x 322 mm x 132 mm
(11-1/16" x 12-11/16" x 5-3/16")
Nail feed system Reciprocating piston type
Nail capacity 150 to 300 (1 roll)
Air consumption 2.3 ltr/cycle at 20 kgf/cm2
(.081 ft3/cycle at 280 psi) (2.3 ltr/cycle at 20 bar)
Air inlet Air plug for high pressure nailer
Air hose Air hose for high pressure nailer
(Inner diam.: 5 to 6 mm (13/64” to 15/64”))
Packaging Corrugated cardboard box (sleeve type)
Packaging dimensions
(Length x Height x Width)
355 mm x 410 mm x 170 mm
(14" x 16" x 6-11/16")
Standard accessories
• Case (Code No. 886432)
• Eye protector (Code No. 875769)
• Oiler (30 cc) (Code No. 883136)
• Nose cap (A)(Code No. 886889)
Optional accessories
• Pneumatic tool lubricant (1 oz oil feeder) (Code No. 877153)
• Pneumatic tool lubricant (4 oz oil feeder) (Code No. 874042)
• Pneumatic tool lubricant (1) (Code No. 876212)
NOTE: The Model NV 90HMC applies higher punching force than that of conventional nailers. The
customer must therefore procure an air compressor and an air hose designed for high-
pressure nailers.
The air plug of the Model NV 90HMC is exclusively designed for high pressure and cannot be
connected to any air hoses and compressors that are generally used at much lower air
pressures. Never modify the air plug for lower pressure.
SPECIFICATIONS

-4-
2. Nail Selection
The Model NV 90HMC utilizes common wire-collated and sheet-collated nail coils of 150 to 300 round-head
nails. Applicable nail dimensions are shown below. However, genuine HITACHI nail coils should be used to
assure satisfactory nailing quality.
CAUTION: Ensure that nails are as specified in Fig. 1. Using other nails will cause nail jams and
consequent nailer damage.
Fig. 1 • Dimensions of nails
Wire-collated coil nails Sheet-collated coil nails
Min. Max. Min. Max.
3. Nail Punching Force
Fig. 2 shows by type of wood and nail the nailer output energy provided by the supply pressure, and the
nailing energy required for punching nails flush. Air pressure exceeding the intersecting point between
nailer output energy and the required nailing energy for punching nails ensures fully punched nails.
For example, when punching a nail measuring 3.8 mm in dia. x 90 mm in length (0.148" x 3-1/2") into a
workpiece of hemlock with the Model NV 90HMC, pressure of about 19.6 bar (20 kgf/cm2, 280 psi) enables
the nailer to punch the nail flush with the wood surface. Any higher pressure causes the nail head to sink
below the wood surface.
Fig. 2 should be used only as a reference because the values indicated vary depending on the type of
wood, moisture content, and grain of wood.
6 mm
(0.236”)
2.5 mm
(0.099”)
45 mm (1-3/4”)
8.6 mm
(0.339”)
3.8 mm
(0.148”)
90 mm (3-1/2”)
6mm
(0.236”)
2.5 mm
(0.099”)
45 mm (1-3/4”)
6.5 mm
(0.256”)
3 mm
(0.118”)
50 mm (2”)

-5-
Required nailing energy Nailer output energy
Fig. 2 • Required nailing energy and nailer output energy
-5-

-6-
Fig. 3 Fig. 4
4. Adjusting the Nailing Depth
The nailing depth can be adjusted by simply turning the adjuster.
* Adjusting the adjuster (Fig. 3)
• Conduct test punching. If the nail sinks too deep, turn the adjuster knob toward the Shallow position
( mark). If the nail sinks too shallow, turn the adjuster knob toward the Deep position ( mark)
(see Figs. 3 and 4). The nail sink quantity is changed 1 mm per rotation of the adjuster knob.
• Do not push up the pushing lever when turning the adjuster.
• Set the lock lever to the "FREE" position when punching nails.
5. Dual Action Trigger
The Model NV 90HMC is equipped with an automatic mode switching mechanism that automatically
switches between "single sequential actuation mode" and "contact action mode".
(1) Punching operations (automatic switching between single sequential actuation mode and contact action mode)
(1) (2) Nail
driven (3) Nail driven
Single
sequential
actuation
mode
Depress the pushing
lever.
Pull the trigger.
Driven
Depress the pushing
lever.
Not driven
Contact
action
mode
Pull the trigger. Depress the pushing
lever.
Driven
Depress the pushing
lever.
Driven
(2) Precautions on using the dual action trigger
• Nails are not punched even with the pushing lever again pressed against the workpiece and the trigger
pulled in single sequential actuation mode. To punch nails continuously, remove your finger from the
trigger and operate according to the contact action procedure.
• Note that when you raise the Model NV 90HMC from the floor (after pressing the pushing lever against
the floor) with the trigger pulled, single sequential actuation mode is automatically selected. Therefore,
nails are not punched even when you press the pushing lever against the workpiece. Release the
trigger and operate according to the procedure of the desired mode.
Shallow
Deep
A
djuste
r
Lock
Lock leve
r
Free
Flush
Too deep
(Turn the knob
toward shallow
side.)
Too shallo
w
(Turn the
knob toward
deep side.)

-7-
1. Comparison of Specifications (Superior specifications: )
HITACHI
Maker
Model
Item NV 90HMC
(High pressure nailer)
NV 90AB
(Conventional nailer)
P
(High pressure nailer)
Operating pressure
12 to 23 bar
(12 to 23 kgf/cm2)
(170 to 320 psi)
4.9 to 8.3 bar
(5 to 8.5 kgf/cm2)
(70 to 120 psi)
12 to 23 bar
(12 to 23 kgf/cm2)
(170 to 320 psi)
Weight 2.5 kg (5.5 lbs.) 3.0 kg (6.6 lbs.) 2.5 kg (5.5 lbs.)
Dimensions (L x H x W)
281 mm x 322 mm x 132 mm
(11-1/16” x 12-11/16” x 5-3/16”)
292 mm x 389 mm x 132 mm
(11-1/2” x 15-5/16” x 5-3/16”)
294 mm x 327 mm x 129 mm
(11-1/2” x 12-7/8” x 5”)
Punching force ratio 1.3 11.1
Nail capacity 300 nails 300 nails 300 nails
Magazine type Top loading
(Easy nail loading) Top loading Top loading
Blow nozzle Provided None None
Driving depth
adjustment mechanism Tool-less Tool-less Tool-less
Single actuation/contact
actuation selector Automatic Manual Automatic
Nose cap Provided Provided Provided
Free angle plug None None Provided
Outlet (size) Switching type
(ø 7 mm, ø 9 mm)
Fixed type
(ø 8 mm)
Fixed type
(ø 8 mm)
Exhaust direction Forward 360°changeable Side
Handle grip Rubber Rubber Rubber
Trigger lock Provided None Provided
Collation Wire and Sheet Wire Wire and Sheet
Head dia. 8.6 mm (0.339") 7.9 mm (0.311") 7.7 mm (0.303")
Shank dia. 3.8 mm (0.148") 3.8 mm (0.148") 3.8 mm (0.148")
Applicable
nails
Length 45 mm to 90 mm
(1-3/4" to 3-1/2")
45 mm to 90 mm
(1-3/4" to 3-1/2")
45 mm to 90 mm
(1-3/4" to 3-1/2")
COMPARISON WITH SIMILAR PRODUCTS

-8-
1. Safety Instructions
In the interest of promoting the safest and most efficient use of the Model NV 90HMC Nailer by all of our
customers, it is very important when concluding a sale that the salesperson carefully ensure that the buyer
seriously recognizes the importance of the Instruction Manual, and fully understands the precautions listed
on the Warning Label attached to each tool.
A. Instruction manual
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, the Instruction Manual lists general precautions and suggestions on the use of pneumatic tools,
and specific precautions and suggestions on use of the pneumatic nailer, in order to enhance the safe,
efficient use of the tool by the customer.
Salespersons must be thoroughly familiar with the contents of the Instruction Manual to be able to offer
appropriate guidance to customers during sales promotion activities.
B. Warning Label
Each Model NV 90HMC unit is provided with a Warning Label (illustrated below) that lists basic safety
precautions on tool use. Carefully ensure that customers fully understand and follow these precautions
before using the tool.
PRECAUTIONS ON SALES PROMOTION

-9-
C. Related laws and regulations
As nailers and staplers are designed to instantaneously punch nails and staples, there is an ever-present
danger of misfiring and subsequent possible serious injury. Accordingly, close attention to handling is
absolutely necessary at all times. Carefully ensure that the customer is fully aware of the precautions listed
in the Instruction Manual 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.
Europe:
EN 792-13:2000 Hand-held-non-electric power tools-Safety requirements-Part
13: Fastener punching tools
The USA:
OSHA 1926.102 Eye and face protection
1926.302 Power-operated hand tools
ANSI SNT-101-2002 Portable, Compressed-Air-Actuated,
Fastener Punching Tools-Safety Requirements for
D. Precautions on operation
(1) Pay special attention to the pressure, capacity and piping of the air compressor, in order to regulate air
pressure supplied to the Model NV 90HMC within the range from 12 kgf/cm2(170 psi, 12 bar) to 23
kgf/cm2(320 psi, 23 bar). Otherwise the performance, service life and safety of the Model NV 90HMC
may be adversely affected. Be sure to install a regulator when using a high-pressure air compressor
with pressure set to 23 kgf/cm2(320 psi, 23 bar) or more. In this case, adjust the air pressure to 23
kgf/cm2(320 psi, 23 bar) or less.
(2) If the dust in compressed air accumulates on the sliding portion, the Model NV 90HMC will not operate
properly. Lubrication effectively removes dust and also prolongs the service life of the Model NV 90HMC
in terms of maintaining good performance. Therefore, the Model NV 90HMC should be lubricated daily.
Supply five to ten drops of lubricant into the air plug on the Model NV 90HMC.
When not using the tool for an extended period, be sure to supply lubricant and perform idle punching
two or three items to lubricate inside, and then apply a thin coating of lubricant to the steel parts to avoid
rusting.
• The table below shows the applicable lubricant. Please recommend the use of Hitachi nailer/tacker oil
to all customers.
Type of oil Brand or product name
Hitachi pneumatic tool lubricant
Shell sliding oil, Tonna S32
(Old Tonna T32);
Code No. 877153 (1 oz. oil feeder)
Code No. 874042 (4 oz. oil feeder)
Code No. 876212 (1 L (1 quart) can))
(3) Be sure to fully drain the compressor’s tank to prevent deteriorated performance or malfunction of the
Model NV 90HMC due to rusting.
(4) Instruct the customers (especially heavy users) to properly conduct inspection and maintenance.

-10-
1. Troubleshooting and Repair
Problem Possible cause
( *: Most-common cause) Inspection method Corrective action
<Nails>
• Magazine is not loaded
with specified genuine
nails.
• Magazine is loaded with
abnormal nails (e.g., bent
nails, too large or too
small nail heads,
abnormal collation).
• Nails or link pieces are
jammed.
• Link pieces are deformed
or broken.
• Check that the magazine
is correctly loaded with
specified nails.
• Use specified nails.
• Remove abnormal nails
and load the nailer with
proper nails.
<Punching section: Nose,
feeder, feed piston, etc.>
• Sliding resistance of the
feed piston is too high.
• Remove the feed piston
and check the feed piston
sliding surface of the
nose.
• Apply grease to the sliding
surface.
• Polish the scratched
portion with sandpaper.
Replace the parts.
• Nail guide face of the nose
is abnormal (deformed,
burrs or damaged).
• Feed spring or feeder
spring is abnormal
(damaged or fatigued).
• Feeder is abnormal
(damaged or worn).
• Check that the punching
section is not abnormal
(burrs, deformed,
damaged or worn).
• Deburr the nail guide face.
• Correct the deformed part.
• Replace abnormal parts.
• Nails are not correctly
loaded in the groove of the
nose.
• Check that nails are
correctly loaded in the
groove of the nose.
• Load nails in the correct
position in the nose.
• Dust adheres to the feeder
sliding portion of the nose,
or lubrication is needed.
• Remove dust and then
lubricate the sliding
surface.
• Air pressure is too low. • Adjust the air pressure to
12 to 23 bar (12 to 23
kgf/cm2, 170 to 320 psi).
1)
Nails cannot
be punched.
*• Air passage is clogged
with broken pieces of
piston bumper, etc.
*• Feed piston chamber
contains foreign matter
such as broken pieces of
piston bumper, etc.
• Open the nail guide and
perform idle punching to
check the feeder's
operation.
• Remove foreign matter.
Replace the piston
bumper with new one.
• Body ---Remove foreign
matter in the return
air chamber.
• Nose ---Remove foreign
matter in the air
passage and feed
piston chamber.
TROUBLESHOOTING GUIDE

-11-
Problem Possible cause
( *: Most-common cause) Inspection method Corrective action
• Air leaks from the gap
between the body and the
nose.
• Tighten screws and check
the O-rings.
• O-rings are worn or
deformed.
• Replace the O-rings.
• O-rings need lubrication. • Apply grease or lubricant.
<Nail guide section>
• Nail guide face is
abnormal (deformed,
burrs or damaged).
• Check that the nail guide
is not abnormal (worn,
deformed or damaged).
• Correct or replace the
parts.
• Dust adheres inside the
nail guide groove, or
lubrication is needed.
• Remove dust and then
lubricate.
*• Spring is abnormal
(missing, damaged or
fatigued).
• The claw ridge section of
the nail stopper is
abnormal (damaged, worn
or burrs).
• Check the operation of nail
stopper (A) and nail
stopper (B).
• Replace abnormal parts.
<Magazine section>
<Pushing lever>
• Magazine • Check that a nail does not
catch on another nail in
the magazine.
• Check that a nail does not
catch on any part of the
magazine.
• Check the height of the
nail holder.
• Collate the nails correctly
and then reload the nailer.
• Remove burrs or
deformed parts. Replace
the parts.
• Adjust the height of the
nail holder correctly.
• Pushing lever • Check the operation of the
pushing lever.
• Correct or replace the
parts.
<Output section: piston,
driver blade, etc.>
• Air pressure is too low. • Adjust the air pressure to
12 to 23 bar (12 to 23
kgf/cm2, 170 to 320 psi).
*• Piston O-ring is abnormal
(worn or damaged).
• Replace the piston O-ring.
*• Piston bumper is
abnormal.
• Replace the piston
bumper.
• O-ring in the cylinder is
abnormal (removed,
deformed or damaged).
• Reassemble or replace
the parts.
1)
Nails cannot
be punched.
(continued)
• Driver blade is abnormal
(deformed, burrs or
damaged).
• Open the nail guide and
perform idle punching to
check that the driver blade
is returned.
• Correct or replace the part.

-12-
Problem Possible cause
( *: Most-common cause) Inspection method Corrective action
• Cylinder inner surface is
abnormal (packed with
dust or worn).
• Check that nails can be
punched at 4.9 bar (5
kgf/cm2, 70 psi).
• Remove dust and then
lubricate.
• Replace the part.
• Sleeve valve sliding
surface is abnormal
(seized or damaged, or
lubrication needed).
• Perform idle punching to
check punching operation.
• Replace the part.
• Apply grease.
• Sleeve valve rubber is
abnormal (removed or
damaged).
• Sleeve valve spring is
abnormal (fatigued or
damaged).
• Replace the part.
<Control valve section>
• Plunger, valve piston,
valve bushing (A) or valve
bushing (B) is abnormal
(seized or damaged).
• Perform idle punching to
check that the driver blade
is not held in the down
position.
• Replace abnormal parts.
1)
Nails cannot
be punched.
(continued)
• O-rings or sliding surfaces
are worn or need
lubrication.
• Disassemble the control
valve section and check
the O-rings.
• Replace abnormal parts.
• Apply grease.
*• Adjuster is raised too high
for short nails.
• Check that the adjuster is
not raised too high.
• Turn the adjuster lower
(lower the pressure).
• Nails are not completely
fed into the injection port.
*• Unspecified nails are
used.
• See item 1). • See item 1).
*• Driver blade is worn. • Check that the driver
blade tip is not abnormally
worn.
• Replace the part.
2)
Nails are
punched but
bent.
• Workpiece is too hard. • Check if a nail is bent even
when punched into soft
wood.
• Nailer cannot be used
because the material is
beyond its applicable
range.
• Adjuster is incorrectly set. • Set the adjuster to the
optimum position.
• Air pressure is too low.
• Turn the adjuster to the
lowest position and then
punch nails. • Adjust air pressure to
12 to 23 bar (12 to 23
kgf/cm2, 170 to 320 psi).
3)
Nails cannot
be
completely
punched
into the
workpiece:
the heads
cannot be
made flush.
• Workpiece is too hard. • Check if a nail is bent even
when punched into soft
wood.
• Nailer cannot be used
because the material is
beyond its applicable
range.

-13-
Problem Possible cause
( *: Most-common cause) Inspection method Corrective action
*• Driver blade is worn. • Perform idle punching to
check whether the driver
blade protrudes from the
nose tip.
• Replace the part.
*• Piston O-ring is abnormal
(worn or damaged).
• Cylinder inside surface is
abnormal (worn or rough).
• Disassemble the output
section and check the
piston O-ring and inside
the cylinder for
abnormality.
• Replace abnormal parts.
3)
Nails cannot
be
completely
punched
into the
workpiece:
the heads
cannot be
made flush.
(continued) • Sleeve valve sliding
surface is abnormal
(seized or damaged, or
lubrication needed).
• Check the sliding surface
for abnormality and
lubrication.
• Replace abnormal parts.
• Apply grease.
• Check whether the
specified nails are used.
• Check the nails as follows:
• Use specified nails.
• Remove abnormal nails
and load the nailer with
proper nails.
4)
Nails jam.
<Nails>
*• Unspecified nails are
used.
*• Abnormal nails are
mixed.
*• Nail heads are too large
or too small.
[Wire-collated nails]
• Collating wires are
abnormal (broken, failed
welding, deformed or
failure at welding
position).
*• Collating wires are
deformed (deformed in
collation angle or
collation pitch).
[Sheet-collated nails]
*• Collating sheets are
abnormal (deformed or
broken).
• Nails are removed from
the sheets.
[Wire-collated nails]
[Sheet-collated nails]
[Wire-collated nails]
[Sheet-collated nails]
Unit: mm (inch)
Dd
L1L2
6 to 8.6
(0.236 to 0.339)
2.5 to 3.8
(0.099 to 0.148)
19
(0.748)
37.5
(1.476)
Unit: mm (inch)
Dd
6 to 6.5
(0.236 to 0.256)
2.5 to 3
(0.099 to 0.118)

-14-
Problem Possible cause
( *: Most-common cause) Inspection method Corrective action
<Body: Nail feeding is
incomplete.>
• Feeder is worn and the
sliding section abnormal.
• Nail guide face of the nose
or the sliding section of
the feeder is abnormal
(deformed, burrs or
damaged).
• Feed spring or feeder
spring is abnormal
(damaged, fatigued or
removed).
• Open the nail guide and
check the position of the
feeder claw.
• Replace abnormal parts.
<Body: Nail guide section>
• Nail guide section is
abnormal.
• See item "1) Nail guide
section."
• See item "1) Nail guide
section."
<Driver blade does not
return completely.>
• See item "1) Output
section: piston, driver
blade, etc."
• Perform idle or actual
punching to check
whether the driver blade
returns completely.
• See item "1) Output
section: piston, driver
blade, etc."
4)
Nails jam.
(continued)
• Air pressure is too high. • Nails may be jammed if
punched at high pressure
and high speed. Check
the pressure and
punching speed.
• Adjust air pressure within
the range of 12 to 23 bar
(12 to 23 kgf/cm2, 170 to
320 psi).

-15-
OFF ON
Magnified view of B
Control valve section
• Air leakage repair location
2. Possible Causes and Corrections of Air Leakage
1. Air leakage repair location
Section of A - A

-16-
2. Repair procedure
(1) Check the following parts marked with an asterisk " * " for trouble.
(2) Then check the seal parts (with the mark) for excessive wear, flaws and breaks.
(3) Next, check the other possible parts.
[Bold] numbers in the description below correspond to item numbers in the Parts List and exploded
assembly diagram for the Model NV 90HMC.
Possible causes
Air leak point Control valve OFF Control valve ON
Exhaust port Defects on Sleeve Valve Rubber [18] (worn,
cut or flaws), or defects on seal surface of
Upper Cover [5] (damage, deformation or
flaws of part).
Defects on O-Ring (I.D 48.5) [12], O-Ring
[16], O-Ring [20], and O-Ring [21] (worn,
cut or flaws)
Defects on seal surfaces of Exhaust Cover
[15], Sleeve Valve [19] and Cylinder [36]
(damage, deformation or flaws on (
parts)
* Defects on seal surface of Sleeve Valve
[19] (damage, deformation or flaws on the
parts)
Defects on Exhaust Rubber [22] (worn,
deformation or cut)
Defects on O-Ring (I.D 48.5) [12] (worn,
cut or flaws)
Exhaust Cover Loose Nylock Bolt M5 x 65 [4]
Damage on Gasket (C) [17] and Packing
(B) [8]
Defects on seal surfaces of Body Ass'y
[42], Exhaust Cover [15], Plate [9] and
Upper Cover [5] (damage, deformation or
flaws)
Nose1 Loose Nylock High Tension Bolt M7 x 25
[56]
Defects on O-Ring (1AP-3) [106] (worn,
cut or flaws)
Defects on O-Ring (S-34) [46] of Body
Ass'y [42] (cut or flaws) and defects on its
seal part (damage, deformation or flaws on
part)
Nose 2 Defects on O-Ring (S-36) [37] of Cylinder
Plate [38] (worn, cut or flaws)
Defects on O-Ring (S-32) [25] of Cylinder
[36] (worn, cut or flaws)
Defects on seal surfaces of Body Ass'y
[42] and Cylinder Plate [38] (damage,
deformation or flaws of ( parts)
Defects on Piston Bumper [45]
(deformation or crack damage of
parts)
Defects on Piston (H) [11] and Nose [47]
(deformation, dust, or seal surface
defects)
Feed Piston Defects on Feed Piston O-Ring (I.D. 14)
[108] (worn, cut or flaws) or defects on
sliding surface of Nose [47] (worn,
deformation or flaws)
Defects on O-ring (P-9) [107] of Nose [47]
(worn, cut or flaws) or defect on sliding
surface of Feed Piston [109] (worn,
deformation or flaws)
A
B
C
D
E

-17-
Possible causes
Air leak point Control valve OFF Control valve ON
Control valve
exhaust port
Defect on O-Ring (P7-U) [89] of Valve
Piston [91] (worn, cut or flaws)
Defect on O-Ring (I.D 1.8) [94] of Plunger
[95] (worn, cut or flaws)
Defect on O-Ring (S-14) [86] of Valve
Bushing (B) [88] (worn, cut or flaws)
* Defect on inner surface of Body Ass’y [42]
valve chamber ( part)
Defect on O-Ring (1AP-11) [92] and O-
Ring (P9-U) [90] of Valve Piston [91]
(worn, cut or flaws)
Defect on O-Ring (S-16) [87] of Valve
Bushing (B) [88] (cut or flaws)
Defect on O-Ring (1AP-5) [96] of Valve
Bushing (A) [98] (worn, cut or flaws)
* Defect on Valve Plate [24] seal surface
(breaks, deformation, flaws on part)
* Defect on the inner surface of Body Ass’y
[42] valve chamber ( part)
Control valve Defect on O-Ring (S-16) [87] and O-Ring
(S-6) [97] of Valve Bushing (A) [98] (worn,
cut or flaws)
Defect on sliding surface of Plunger [95]
O-Ring (S-6) [97] (deformation or flaws on
part)
Defect on O-Ring (S-16) [87] and O-Ring
(S-6) [97] of Valve Bushing (A) [98] (worn,
cut or flaws)
Defect on sliding surface of Plunger [95]
O-Ring (S-6) [97] (deformation or flaws on
part)
Valve Bushing
(air duster valve
section )
Break of Valve Packing [26]
Defect on O-Ring (1AP-3) [30] (worn, cut or
flaws) or defect on Valve Bushing [33] seal
surface (flaws or breaks on part)
Loose Valve Bushing [33] screw (left-
handed thread)
Cap (Defects on O-Ring (I.D 37.2) [61] (worn,
cut or flaws))
Loose Cap (Gold) [62] screw (left-handed
thread)
Defects on seal surface of Body Ass'y [42]
and Cap (Gold) [62] (damage, deformation
or flaws on part)
F
G
H
I