Hitachi WH 9DM2 Manual

TECHNICAL DATA
AND
SERVICE MANUAL
CORDLESS IMPACT DRIVER
WH 9DM2
CORDLESS IMPACT WRENCH
WR 9DM2
SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT
LIST Nos. WH 9DM2: G801
WR 9DM2: G802
Mar. 2004
G
MODELS
WH 9DM2
WH 9DM2 WR 9DM2
WR 9DM2
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:
Symbol Utilized
Competitor
Company Name Model Name
CMAKITA BTD061
WH 9DM2
Symbol Utilized
Competitor
Company Name Model Name
CMAKITA 6991D
WR 9DM2

Page
CONTENTS
1. PRODUCT NAME ...........................................................................................................................1
2. MARKETING OBJECTIVE .............................................................................................................1
3. APPLICATIONS ..............................................................................................................................1
4. SELLING POINTS ..........................................................................................................................2
4-1. Selling Point Descriptions .............................................................................................................. 4
5. SPECIFICATIONS ..........................................................................................................................7
5-1. Specifications ................................................................................................................................. 7
5-2. Optional Accessories ..................................................................................................................... 9
6. COMPARISONS WITH SIMILAR PRODUCTS ............................................................................12
6-1. Specification Comparisons (Cordless Impact Driver) .................................................................. 12
6-2. Specification Comparisons (Cordless Impact Wrench) ............................................................... 13
6-3. Tightening Torque ........................................................................................................................ 14
6-4. Tightening Speed ......................................................................................................................... 17
6-5. Number of Screws or Bolts Driven ............................................................................................... 18
7. PRECAUTIONS IN SALES PROMOTION ...................................................................................19
7-1. Safety Instructions ....................................................................................................................... 19
7-2. Tightening Torque Inspection Prior to Operation ......................................................................... 21
7-3. Tightening Torque Variation ......................................................................................................... 21
7-4. Suggestions and Precautions for the Efficient Use of the Charger .............................................. 22
8. OTHER PRECAUTIONS ..............................................................................................................23
9. REPAIR GUIDE ............................................................................................................................24
9-1. Precautions in Disassembly and Reassembly ............................................................................. 24
9-2. Precautions in Disassembly and Reassembly of Battery Charger .............................................. 33
10. STANDARD REPAIR TIME (UNIT) SCHEDULES .....................................................................34
Assembly Diagram for WH 9DM2
Assembly Diagram for WR 9DM2

--- 1 ---
1. PRODUCT NAME
Hitachi Cordless Impact Driver, Model WH 9DM2
Hitachi Cordless Impact Wrench, Model WR 9DM2
2. MARKETING OBJECTIVE
The new cordless impact driver Model WH 9DM2 ("Super Impact 9") and the new cordless impact wrench Model
WR 9DM2 ("Super Wrench 9") are brought out as DC 9.6 V products of the Super Impact series. They are
upgraded versions of the current Models WH 9DM and WR 9DM, developed to expand the market share and the
sales.
The new Model WH 9DM2 provides the lower maximum tightening torque 80 N•m than that of the current Model
WH 9DM (95 N•m). This is to realize a lightweight and compact driver (overall length 20 mm, product weight
200 g). The Model WH 9DM2 is very convenient for tightening small screws such as sash screws requiring less
tightening torque.
The new Model WR 9DM2 provides the class-top tightening torque 120 N•m that is 40% higher than the current
Model WR 9DM.
3. APPLICATIONS
•Tightening/loosening of small screws, tapping screws, wood screws, bolts, nuts, etc.
•Drilling into wood and various other materials (with use of optional accessory drill chuck adapter).
[Applicable Markets]
•Wood-product assembly: Tightening/loosening of wood screws, lag bolts, etc.
•Construction industry: Assembly of scaffolding, roofing, aluminum sashes, fencing, etc.; removal of plastic cones
from concrete forms, mounting/removal of form ties; drilling into the wood frames of concrete forms, etc.
•Manufacturing industry: Assembly work for automobiles, rolling stock, shipbuilding, agricultural machinery and
tools, industrial machines, steel furniture, etc.
•Utility industry: Assembly and installation of electric equipment, plumbing facilities, air conditioning (duct
assembly, etc.), sanitary fixtures and various other facilities.
•Service industry: General repair work; installation of advertising signs, automobile repair, assembly of garages
and carports storage sheds, etc.
•Various other assembly, construction or repair facilities.

--- 2 ---
Selling points common to the Model
WH 12DM2
New design
Elastomer is new titanium silver color.
Protector is standard.
Convenient light equipped hook
High durability, dust resistance and
long service life
Advanced case (excellent
accommodation)
4. SELLING POINTS
(1) Cordless impact driver Model WH 9DM2
The shortest overall length in the class
147 mm
Convenient for work in narrow places
Lightweight 1.2 kg
Easy to operate for a long time
Easily portable
30% lower striking start torque
Optimum for light-duty works such as
tightening sash screws, plastic screws
and Teks screws

--- 3 ---
(2) Cordless impact wrench Model WR 9DM2
9.5 mm (3/8")
(Reference) WR 12DM2: 12.7 mm (1/2")
Selling points common to the Model
WR 12DM2
New design
Elastomer is new titanium silver color.
Protector is standard.
Convenient light equipped hook
High durability, dust resistance and
long service life
Advanced case (excellent
accommodation)
Class-top tightening torque
120 N•m {1220 kgf•cm}
C: 100 N•m
Compact
Overall length 160 mm
C: 168 mm

--- 4 ---
4-1. Selling Point Descriptions
Refer to pages 4 through 10 of Technical Data Service Manual for the Models WH 12DM2/WR 12DM2 for
common selling points.
Model WH 9DM2
(1) The shortest overall length in the class 147 mm / light weight 1.2 kg
To realize a lightweight and compact driver, the Model WH 9DM2 provides the lower maximum tightening
torque 80 N•m than that of the current Model WH 9DM (95 N•m).
Comparison of the armature
Comparison of the decelerating unit
WH 9DM2 WH 9DM C
Product Unit
Overall length mm
Weight g
Hitachi
WH 9DM2
22.6 (57/64")
30 (0.066 lbs.)
Hitachi
WH 9DM
25.2 (63/64")
53 (0.117 lbs.)
C
25.5 (1")
44 (0.097 lbs.)
1
2
Equipped with a new rare-earth magnet motor having 1.2 times greater magnetic force (Same as the Model
WH 12DM2)
The Model WH 9DM2 is equipped with a new rare-earth magnet motor that is smaller than the Model WH 9DM
by 30% while providing higher power.
Equipped with a reinforced plastic gear for the decelerating unit
The gear is made of heat-resistant nylon resin reinforced with fiberglass.
It is lightweight and strong. In addition, the gear is uniquely shaped so
that the gear itself has the cushioning function. The Model WH 9DM2 is
lightweight thanks to deletion of the damper (a cushioning part) that is
used in the Model WH 12DM2. Cushioning
function
Product Unit
mm
Overall length mm
Weight g
Thickness
Hitachi
WH 9DM2
12 (15/32")
79 (7/64")
92 (0.2 lbs.)
Hitachi
WH 9DM
17 (43/64")
86 (25/64")
111 (0.25 lbs.)
C
12.5 (1/2")
74 (29/32")
75 (0.17 lbs.)

--- 5 ---
Product Unit
Overall length mm
Weight g
Hitachi
WH 9DM2
48.6 (1-29/32")
160 (0.35 lbs.)
Hitachi
WH 9DM
57.6 (2-17/64")
214 (0.47 lbs.)
C
57.0 (2-15/64")
175 (0.39 lbs.)
WH 9DM2 WH 9DM C
Product Unit
mm
Center height mm
Height mm
Overall length
Measured value kg
kgCatalog value
Weight
Hitachi
WH 9DM2
147 (5-25/32")
26.5 (1-3/64")
223 (8-25/32")
1.2 (2.6 lbs)
1.29 (2.8 lbs)
Hitachi
WH 9DM
167 (6-37/64")
26 (1-1/64")
221 (8-45/64")
1.4 (3 lbs)
1.46 (3.2 lbs)
164 (6-29/64")
25 (1-63/64")
236 (9-5/16")
1.1 (2.4 lbs)
1.13 (2.5 lbs)
C
Model
WH 9DM
C
Number of trigger switch depressing
0.68 N•m {6.9 kgf•cm, 6.0 in-lbs.}
2.0 times
(Reference) WH 12DM2
WH 9DM2 8.6 times
5.0 times
7.4 times
0.95 N•m {9.7 kgf•cm, 8.4 in-lbs.}
0.71 N•m {7.2 kgf•cm, 6.2 in-lbs.}
1.26 N•m {12.8 kgf•cm, 11.1 in-lbs.}
Table 1
3
(2) 30% lower striking start torque
The Model WH 9DM2 has lower striking start torque 0.68 Nm {6.9 kgf•cm, 6.0 in-lbs} than the current Model
WH 9DM (0.95 Nm {9.7 kgf•cm, 8.4 in-lbs}) to minimize damage to the screws. Thanks to the lower striking
start torque, the Model WH 9DM2 is optimum for light-duty works such as tightening sash screws, plastic
screws and Teks screws because it gives less damage to the small screws and the workpieces.
Table 1 shows a comparison of number of trigger switch operations when tightening a tapping screw D4 x 25
in a workpiece of nylon resin (prepared hole diameter 3.5 mm) until each driver idles. The Model WH 9DM2
has the highest resistance to idling because the number of adjustments is most frequent. (The switch is
turned off immediately after striking is started. The higher the striking start torque, the longer tightening time is
required and the driver is apt to idle.)
Compact and lightweight hammer assembly
The hammer assembly is newly designed according to the maximum tightening torque 80 N•m.
Comparison of the hammer assembly
4
Appearance and dimensions
Cordless impact driver: Model WH 9DM2
Striking start torque
* The data above are intended for reference purpose only because actual number of trigger
switch depressing may vary depending on tightening conditions.

--- 6 ---
Model WR 9DM2
(1) Class-top tightening torque 120 N•m (1220 kgf•cm, 1060 in-lbs.)
The right graph shows a comparison of tightening torque when
tightening an M12 high-strength bolt with a hexagonal socket
(overall length 33 mm) for 3 seconds. The Model WR 9DM2
provides the class-top tightening torque that is 40% higher than
the current Model WR 9DM and 30% higher than C.
Product Unit
mm
Center height mm
Height mm
Overall length
Measured value kg
kgCatalog value
Weight
Hitachi
WR 9DM2
160 (6-19/64")
26.5 (1-3/64")
223 (8-25/32")
1.4 (3 lbs.)
1.43 (3.1 lbs.)
Hitachi
WR 9DM
167 (6-37/64")
26 (1-1/64")
221 (8-45/64")
1.4 (3 lbs.)
1.46 (3.2 lbs.)
168 (6-39/64")
26 (1-1/64")
231 (9-3/32")
1.4 (3 lbs.)
1.49 (3.3 lbs.)
C
122
88 93
160
140
120
100
80
60
40
20
0
WR 9DM2 WR 9DM C
Tightening torque
(N.m)
(2) Compact
The overall length of the Model WR 9DM2 is 7 mm shorter than the current Model WR 9DM and 8 mm shorter
than C. It is convenient for work in narrow places.
Cordless impact wrench: Model WR 9DM2

--- 7 ---
5. SPECIFICATIONS
5-1. Specifications
Model Cordless impact driver
WH 9DM2
Capacity
Item
Cordless impact wrench
WR 9DM2
Small screw M4 --- M8 (5/32" --- 5/16")*1
Ordinary bolt M5 --- M12 (3/16" --- 15/32")
Ordinary bolt M6 --- M14 (1/4" --- 9/16")
High-strength bolt M6 --- M10 (1/4" --- 3/8")
Tightening torque 80 N•m (820 kgf •cm, 710 in-lbs.)*2120 N•m (1220 kgf •cm, 1060 in-lbs.)*3
Tip condition 6.35 mm (1/4") Bit holder 9.5 mm (3/8") Square drive
Type of motor Fan cooled DC magnet motor
Enclosure Main body: Polyamide resin •••••• Housing
Aluminum alloy die casting •••••• Hammer case
Storage battery: ABS resin (black)
Charger: ABS resin (black)
Type of switch
Trigger switch with forward/reverse changeover pushing button (with brake and variable)
Handle configuration T-type
No-load rotational speed 0 --- 2,800 /min
Impact rate 0 --- 3,200 /min
Main body 1.2 kg (2.6 lbs.)
Battery 0.55 kg (1.2 lbs.)
Overall length x height 147 mm (5-25/32") x 223 mm (8-25/32")
Center height 26.5 mm (1-3/64")
Battery (Type EB 9B) Sealed cylindrical nickel-cadmium batteries
Nominal voltage: DC 9.6V
Nominal life: Charging/discharging approximately 1,000 cycles (in the case of Model
UC 14YF2, UC 14YFA)
Nominal capacity: 2.0 Ah
160 mm (6-37/64") x 223 mm (8-25/32")
Battery (Type EB 930H) Sealed cylindrical nickel-metal hydride batteries
Nominal voltage: DC 9.6V
Nominal life: Charging/discharging approximately 500 cycles (in the case of Model
UC 14YF2, UC 14YFA)
Nominal capacity: 3.0 Ah
Charger (UC 14YF2) Charger power source: single-phase AC, 50/60 Hz
Voltage: Depending on the order specification
Power input: 44 W
Charging system: Constant current charge with full wave phase control
Overcharge protection system: (1) Battery voltage detection ( 2V system)
(2) Battery surface temperature detection
(thermostat or thermistor)
(3) 120-minute timer
Output voltage: 7.2 V --- 14.4 V
Output current: 1.9 A
Charging time: Approx. 60 minutes (for B-type storage battery at 20 ˚C)
Approx. 90 minutes (for H-type storage battery at 20 ˚C)
Product weight: 1.3 kg
Operable ambient temperature range: 0 ˚C --- 40 ˚C
The maximum allowable temperature of the EB 9B type battery is 60 ˚C and the
EB 930H type battery is 45 ˚C.
Weight
0 --- 2,600 /min
1.4 kg (3.0 lbs.)

--- 8 ---
Charger power source: Single-phase AC, 50/60 Hz
Voltage: Depending on the order specification
Power input: 56 W
Charging system: Constant current charge with feedback control
Overcharge protection system: (1) Battery voltage detection ( 2V system)
Battery temperature detection (dT/dt system)
for Ni-MH battery
(2) Battery surface temperature detection
(thermistor)
(3) 120-minute timer
Output voltage: 7.2 V --- 14.4 V
Output current: 2.6 A
Charging time: Approx. 50 minutes (for B-type storage battery at 20 ˚C)
Approx. 70 minutes (for H-type storage battery at 20 ˚C)
Product weight: 0.6 kg
Operable ambient temperature range: 0 ˚C --- 40 ˚C
The maximum allowable temperature of the EB 9B type battery is 55˚C and the
EB 930H type battery is 45 ˚C.
*1: In the case of tapping screws and wood screws, a minimum of M3 (1/8") is possible.
*2: This torque is based on tightening an M12 (15/32") bolt (strength grade: 12.9) for 3 seconds with a hexagonal socket.
*3: This torque is based on tightening an M12 (15/32") bolt (strength grade: 12.9) for 3 seconds with a hexagonal socket.
*4: Main body does not include accessory tools and hook (hexagonal bit etc.).
Charger (For UC 14YFA)
Prior to charging
During charging
Charging completed
Charging not
possible
High battery
temperature
Blinks
Lit
Blinks
Flickers
Lit
0.5 sec ON, 0.5 sec OFF
Stays ON constantly
0.5 sec ON, 0.5 sec OFF
0.1 sec ON, 0.1 sec OFF
Stays ON constantly
Pilot lamp indications (Models UC 14YF2 and UC 14YFA)
Red pilot lamp
remains lit or flashes.
Green pilot lamp is lit.
Storage battery or charger
is faulty.
Charging not possible
because storage battery
temperature is too high.

--- 9 ---
5-2. Optional Accessories
(1) Optional accessories for the Model WH 9DM2
•Plus driver bit
50 mm (2")
Bit No.
No. 2
No. 3
Code No.
992671
992672
•Hexagon socket
L
B
Stamped figures
9961778 (5/16")65 (2-9/16")8
Stamped figures
5 mm Hexagon socket
Part name L
(mm)
B
(mm) Code No.
98532910 (3/8")65 (2-9/16")106 mm Hexagon socket
99617812 (15/32")65 (2-9/16")125/16" Hexagon socket
99617913 (1/2")65 (2-9/16")138 mm Hexagon socket
99618014 (9/16")65 (2-9/16")1410 mm Hexagon socket (small type)
99618116 (5/8")65 (2-9/16")1610 mm Hexagon socket
99618217 (21/32")65 (2-9/16")1710 mm Hexagon socket
99619721 (53/64")166 (6-17/32")211/2" Hexagon long socket
•Woodworking drill bit (Code No. 959183)
14 mm dia.
(35/64")
83 mm (3-17/64")
•Drill chuck adaptor set (Code No. 996195)
The drill chuck adaptor set permits mounting of various types of locally-available drill bits for a variety of drilling
operations.

--- 10 ---
(2) Optional accessories for the Model WR 9DM2
•Primary dimensions and applicable bolts for accessory hexagon sockets:
8 mm
10 mm
12 mm
13 mm
14 mm
16 mm
17 mm
18 mm
19 mm
13 (1/2")
16 (5/8")
19 (3/4")
20 (25/32")
21 (13/16")
24 (15/16")
25 (1")
26 (1-1/32")
27.5 (1-1/16")
33 (1.5/16")
33 (1.5/16")
33 (1.5/16")
33 (1.5/16")
33 (1.5/16")
33 (1.5/16")
33 (1.5/16")
33 (1.5/16")
33 (1.5/16")
B
B
C
B
B
D
D
D
D
8 (5/16")
10 (3/8")
12 (15/32")
13 (1/2")
14 (9/16")
16 (5/8")
17 (21/32")
18 (23/32")
19 (3/4")
W 5/16"
W 3/8"
W 7/16"
M 5 (3/16")
M 6 (1/4")
M 8 (5/16")
M 10 (3/8")
(M 10) ( 3/8" )
M 12 (15/32")
(M 12) (15/32")
996125
996126
996127
996128
996129
996130
996131
996132
996133
Hexagon socket
9.5 (3/8")
Square
drive
dimension
Sq (mm)
Part
name
Code
No.
Nominal diameter of applicable bolts
Dihedral
width
H (mm)
Shape
Socket primary dimensions (mm)
ISO
(Ordinary)
ISO
(Small) Inch LL1φD1
M 8 (5/16")
M 10 (3/8")
M 12 (15/32")
M 14 (9/16")
5 (3/16")
6 (1/4")
7 (9/32")
8 (5/16")
8 (5/16")
9 (11/32")
10 (3/8")
10 (3/8")
12 (15/32")
19 (3/4")
19 (3/4")
19 (3/4")
22 (7/8")
22 (7/8")
22 (7/8")
22 (7/8")
22 (7/8")
22 (7/8")
φD2
a
a
a
b
b
b
b
b
b
Socket pin
Shape B Shape C Shape D Sq
φ
φ
φ
φ
a
a
a
b
b
b
b
b
b
•Primary dimensions and applicable bolts for accessory long sockets:
Shape B Shape D
8 mm
10 mm
12 mm
13 mm
14 mm
16 mm
17 mm
18 mm
19 mm
48 (1-7/8")
48 (1-7/8")
48 (1-7/8")
48 (1-7/8")
48 (1-7/8")
48 (1-7/8")
48 (1-7/8")
48 (1-7/8")
48 (1-7/8")
60 (2-3/8")
60 (2-3/8")
60 (2-3/8")
60 (2-3/8")
60 (2-3/8")
60 (2-3/8")
60 (2-3/8")
60 (2-3/8")
60 (2-3/8")
B
B
B
B
B
D
D
D
D
8 (5/16")
10 (3/8")
12 (15/32")
13 (1/2")
14 (9/16")
16 (5/8")
17 (21/32")
18 (23/32")
19 (3/4")
W 5/16"
W 3/8"
W 7/16"
M 5 (3/16")
M 6 (1/4")
M 8 (5/16")
M 10 (3/8")
(M 10) (3/8")
M 12 (15/32")
(M 12) (15/32")
996134
996135
996136
996137
996138
996139
996140
996141
996142
Long socket
9.5 (3/8")
Square
drive
dimension
Sq (mm)
Part
name
Code
No.
Nominal diameter of applicable bolts
Dihedral
width
H (mm)
Shape
Socket primary dimensions (mm)
ISO
(Ordinary)
ISO
(Small) Inch LL1
M 8 (5/16")
M 10 (3/8")
M 12 (15/32")
M 14 (9/16")
12 (15/32")
12 (15/32")
14 (9/16")
14 (9/16")
15 (19/32")
15 (19/32")
15 (19/32")
16 (5/8")
17 (21/32")
φD1
Socket pin
19 (3/4")
19 (3/4")
19 (3/4")
22 (7/8")
22 (7/8")
22 (7/8")
22 (7/8")
22 (7/8")
22 (7/8")
13 (1/2")
16 (5/8")
18.4 (22/32")
18.9 (3/4")
19.5 (49/64")
24 (15/16")
25 (1")
26 (1-1/32")
27.5 (1-1/16")
φD2
Sq
[NOTE] Although the ISO (Ordinary) M10 (3/8") and M12 (15/32") bolts listed in hexagon sockets and long sockets
are from the old standards of the International Standard Organization, they are still commonly available
in international markets.
L2
φ
φ
φ

--- 11 ---
•Bit adaptor (Code No. 996144):
6.35 (1/4") 40 (1-9/16")
13.5 mm dia.(17/32")
9.5 (3/8")
• Extension bar [Overall length 100 mm (3-15/16") ] ............................................................ Code No. 996143
• Universal joint .................................................................................................................... Code No. 996147
• 12.7 mm (1/2") square adapter ass'y [Overall length 36 mm (1-13/32")] ........................... Code No. 996145
Square drive dimensions: Anvil side 9.5 mm (3/8")
Socket side 12.7 mm (1/2")
Part name Overall length Code No.
Cross-recessed (Phillips) hd. driver bit No.2 45 955229
70 955654
45 955230
70 955655
Cross-recessed (Phillips) hd. driver bit No.3

--- 12 ---
6. COMPARISONS WITH SIMILAR PRODUCTS
6-1. Specification Comparisons (Cordless Impact Driver)
M 4 --- M 8
(5/32" --- 5/16")
HITACHI
WH 9DM2 WH 9DM
C
Maker
Model
Item
M 4 --- M 8
(5/32" --- 5/16")*1
M 4 --- M 8
(5/32" --- 5/16")
Catalog specifications
Capacity
Small screw
M 5 --- M 12
(3/16" --- 15/32")
M 5 --- M 12
(3/16" --- 15/32")
M 5 --- M 12
(3/16" --- 15/32")
Ordinary bolt
M 5 --- M 10
(3/16" --- 3/8")
M 5 --- M 10
(3/16" --- 3/8")
M 5 --- M 10
(3/16" --- 3/8")
High-strength bolt
80
(820 kgf•cm, 710 in-lbs.)
95
(970 kgf•cm, 840 in-lbs.)
65
(663 kgf•cm, 575 in-lbs.)
Max. tightening torque*2N•m
0 --- 2,800 0 --- 2,300 0 --- 2,500No-load rotation speed /min
0 --- 3,200 0 --- 3,000 0 --- 3,000Impact rate /min
1.2 (2.6 lbs) 1.4 (3.0 lbs) 1.1 (2.4 lbs)
Main body weight kg
82
(835 kgf•cm, 725 in-lbs.)
99
(1010 kgf•cm, 877 in-lbs.)
65
(663 kgf•cm, 575 in-lbs.)
Max. tightening torque N•m
Measured figures
0 --- 2,570 0 --- 2,360 0 --- 2,640No-load rotation speed /min
0 --- 3,190 0 --- 2,870 0 --- 2,850Impact rate /min
147 x 223
(5-25/32" x 8-25/32")
167 x 221
(6-37/64" x 8-45/64")
Overall length x height mm 164 x 236
(6-29/64" x 9-5/16")
26.5 (1-3/64") 26 (1-1/64") 25 (1-63/64")Center height mm
1.29 (2.8 lbs) 1.46 (3.2 lbs) 1.13 (2.5 lbs)Main body weight kg
70 69 70
No-load sound pressure level
dB(A)
Driver chuck Driver chuck Driver chuck
Tool tip mounting system
Trigger switch with
forward/reverse
changeover pushing
button with brake and
variable
Type of switch
Trigger switch with
forward/reverse
changeover pushing
button with brake and
variable
Trigger switch with
forward/reverse
changeover pushing
button with brake and
variable
DC magnet DC magnet DC magnet
Type of motor
9.6 9.6 9.6
Voltage
21 24 15
Current
EB 9B or EB 930H EB 9B or EB 930H BH9020
Battery
V
A
Type
EB 9B: 2.0
EB 930H: 3.0
EB 9B: 2.0
EB 930H: 3.0 BH9020: 2.0
Nominal capacity Ah
9.6 9.6 9.6
Nominal voltage V
0 --- 40 0 --- 40 ------
Ambient temperature
˚C
UC 14YF2 or UC 14YFA UC 14YF2 DC 14RA
Model
44 or 56 44 ------
Power input capacity
VA
7.2 --- 14.4 7.2 --- 14.4 7.2 --- 14.4
Recharging voltage
V
•Plastic tool case
•Charger (UC 14YF2 or
UC 14YFA)
•Plastic tool case
•Charger (UC 14YF2)
•Plastic tool case
•Charger (DC14RA)
Standard accessories
Charger
*1: In the case of tapping screws and wood screws, a minimum of M3 (1/8") is possible.
*2: Max. tightening torque is based on tightening an M12 (5/32") bolt (strength grade: 12.9) for 3 seconds with a hexagon
socket.
*3: Main body weight does not include accessory tools (hexagon bit etc.).
*1
*3
*2
*3

--- 13 ---
6-2. Specification Comparisons (Cordless Impact Wrench)
HITACHI
WR 9DM2
Maker
Model
Item
Catalog specifications
Capacity
M 6 --- M 14
(1/4" --- 9/16")
Ordinary bolt
M 6 --- M 10
(1/4" --- 3/8")
High-strength bolt
88.2
(900 kgf•cm, 780 in-lbs.)
Max. tightening torque N•m
0 --- 2,600
No-load rotation speed /min
0 --- 3,200
Impact rate /min
1.4 (3.0 lbs.)
Main body weight kg
122
(1240 kgf•cm, 1076 in-lbs.)
Max. tightening torque N•m
Measured figures
0 --- 2,460
No-load rotation speed /min
0 --- 3,230
Impact rate /min
160 x 223
(6-19/64" x 8-25/32")
Overall length x height mm
26.5 (1-3/64")
Center height mm
1.43 (3.1 lbs.)
Main body weight kg
70
No-load sound pressure level
dB(A)
Trigger switch with
forward/reverse
changeover pushing
button with brake and
variable
Type of switch
DC magnet
Type of motor
9.6
Voltage
27
Current
EB 9B or EB 930H
Battery
V
A
Type
EB 9B: 2.0
EB 930H: 3.0
Nominal capacity Ah
9.6
Nominal voltage V
0 --- 40
Ambient temperature
˚C
UC 14YF2 or UC 14YFA
Model
44 or 56
Power input capacity
VA
7.2 --- 14.4
Recharging voltage
V
Plastic tool case
Charger (UC 14YF2
or UC 14YFA)
Standard accessories
Charger
*1: Max. tightening torque is based on tightening an M12 (5/32") bolt (strength grade: 12.9) for 3 seconds with a hexagon
socket.
*2: Main body weight does not include accessory tools (hexagon bit etc.).
*1
*2
*1
*2
WR 9DM
M 6 --- M 14
(1/4" --- 9/16")
M 6 --- M 10
(1/4" --- 3/8")
120
(1220 kgf•cm, 1060 in-lbs.)
0 --- 2,300
0 --- 3,000
1.4 (3.0 lbs.)
88.2
(900 kgf•cm, 780 in-lbs.)
0 --- 2,360
0 --- 3,185
167 x 221
(6-37/64" x 8-45/64")
26 (1-1/64")
1.46 (3.2 lbs.)
69
Trigger switch with
forward/reverse
changeover pushing
button with brake and
variable
DC magnet
9.6
24
EB 9B or EB 930H
EB 9B: 2.0
EB 930H: 3.0
9.6
0 --- 40
UC 14YF2
44
7.2 --- 14.4
Plastic tool case
Charger (UC 14YF2)
Retaining ring
Tool tip mounting system Plunger
9.5 mm (3/8") square drive
Tip condition 9.5 mm (3/8") square drive
M 8 --- M 14
(5/16" --- 9/16")
M 6 --- M 10
(1/4" --- 3/8")
0 --- 2,300
0 --- 3,000
1.4 (3.0 lbs.)
93
(950 kgf•cm, 825 in-lbs.)
0 --- 2,300
0 --- 2,885
26 (1-1/64")
1.49 (3.3 lbs.)
69
Trigger switch with
forward/reverse
changeover pushing
button with brake and
variable
DC magnet
9.6
22
9122
9.6
---
DC1411
---
7.2 --- 14.4
Retaining ring
9.5 mm (3/8") square drive
C
100
(1020 kgf•cm, 885 in-lbs.)
168 x 231
(6-39/64" x 9-3/32")
2.0
Plastic tool case
Charger (DC1411)

--- 14 ---
6-3. Tightening Torque
6-3-1. Tightening torque characteristic comparisons
(1) Impact driver
Thanks to the high-power rare-earth magnet motor and the computer analysis, the Model WH 9DM gives
optimum impact at tightening screws and the tightening torque is increased.
Fig. 1-1
Fig. 1-2
Test conditions
Bolt: M12 x 45 mm (15/32" x 1-3/4")
(strength grade: 12.9)
Steel plate: Mild steel
M12 (15/32") Thickness = 25 mm (1")
Accessory tool: Hexagon socket ass'y
(2) Impact wrench
Test conditions
Bolt: M12 x 45 mm (15/32" x 1-3/4")
(strength grade: 12.9)
Steel plate: Mild steel
M12 (15/32") Thickness = 25 mm (1")
Accessory tool: Hexagon socket ass'y
WH 9DM WH 9DM2
200
(174 in-lbs.)
0123
400
(347 in-lbs.)
600
(521 in-lbs.)
800
(694 in-lbs.)
1000
(868 in-lbs.)
kgf
.
cm
Tightening time
Tightening torque
C
1200
(1042 in-lbs.)
N
.
m
120
100
80
20
40
60
0
0
(sec.)
WR 9DM2
C
200
(174 in-lbs.)
0123
400
(347 in-lbs.)
600
(521 in-lbs.)
800
(694 in-lbs.)
1000
(868 in-lbs.)
kgf
.
cm
Tightening time
Tightening torque
WR 9DM
1200
(1042 in-lbs.)
N
.
m
120
100
80
20
40
60
0
0
(sec.)
140
0
1400
(1215 in-lbs.)

--- 15 ---
6-3-2. Screw diameter and appropriate tightening torque
Generally speaking, the appropriate tightening torque for a screw can be determined by the strength grade of the
screw and the material tightened. Tables 1 and 2, and Fig. 2 below list data relative to the strength grade of
various screws and the appropriate tightening torque. For further reference, appropriate tightening torque is
calculated with the following formula. Study and use this formula for accurate selection of tightening torque.
T=k•d•p
T: Appropriate tightening torque (kgf•cm)
k: Torque coefficient (0.17)
d: Nominal diameter for the screw (mm)
p: Recommended axial tightening force to be applied to the screw (kgf)
p=rated axial stress (kgf/cm2) x 0.8 x effective sectional area of the thread (mm2)
•Strength grade and rated axial stress of threads
Strength grade
Rated axial stress (kgf/mm2)
Material
Heat treatment
4.8 6.8 8.8 12.9
29.1 43.7 58.2 95
Mild steel Alloy steel including Ni, Mn, Cr, etc.
None Processed-hard material
•Diameter and effective sectional areas of threads
Kind of thread (x pitch)
Effective sectional area of
thread (mm2)
M5 x 0.8 mm
(3/16")
14.2
M6 x 1 mm
(1/4")
20.1
M8 x 1.25 mm
(5/16")
36.6
M10 x 1.5 mm
(3/18")
58.0
M12 x 1.75 mm
(15/32")
84.3
M14 x 2 mm
(9/16")
115
•Thread diameter and appropriate tightening torque
Fig. 2
Strength grade 12.9
(high-strength bolt)
Strength grade 8.8
(high-strength bolt)
Strength grade 6.8
(ordinary bolt)
Strength grade 4.8
(ordinary bolt)
0
0
5
(3/16")
6
(1/4")
8
(5/16")
10
(3/8")
12
(15/32")
14
(9/16")
mm
200
(19.6 N
•
m, 14 ft-lbs)
400
(39.2 N
•
m, 29 ft-lbs)
600
(58.8 N
•
m, 43 ft-lbs)
800
(78.4 N
•
m, 58 ft-lbs)
1000
(98 N
•
m, 72 ft-lbs)
1200
(117.6 N
•
m, 86 ft-lbs)
(kgf
•
cm)
Thread diameter
Appropriate tightening torque
Table 1
Table 2

--- 16 ---
6-3-3. Bolt tightening torque characteristics
Figures 3-1 and 3-2 show relationships between time and tightening torque for individual bolt types and sizes.
While the data are useful for handy reference, actual tightening torque will vary depending on tightening
conditions and other variables. For details, please refer to Para. 7-3, "Tightening Torque Variation".
(Note)
•The term "tightening time" indicates the impact time after the lower surface of the bolt has come in contact with
the material into which it is being tightened.
•In the tightening conditions shown in Figs. 6-1 and 6-2, the screws are being tightened directly into a steel
plate; accordingly, the torque goes up very abruptly in comparison with ordinary bolt tightening conditions.
Fig. 3-2
Bolt
Nut
Steel plate
thickness: t
* The following bolts were utilized:
Ordinary bolt; strength grade 4.8
High-strength bolt; strengh grade
12.9
Strength grade is read as follows:
4.8
Yield point or durable force:
(45,500 psi)
Tensile strength of the bolt:
(56,900 psi)
0123
kgf .cm
(in-lbs.)
Tightening time: sec.
(Steel plate thickness: t=3/8"(10 mm))
5/16" x 1-3/6"
(M8 x 30)
Tightening torque
High-strength bolt
00
20
40
60
80
100
N.m
01 23
kgf .cm
(in-lbs.) 3/8" x 1-3/16"
(M10 x 30)
Tightening torque
High-strength bolt
00
20
40
60
80
100
N.m
Ordinary bolt
0123
15/32" x 1-3/4"
(M12 x 45)
High-strength bolt
Ordinary bolt
kgf .cm
(in-lbs.)
Tightening torque
00
20
40
60
80
100
N.m
1200
(1042)
120
200
(174)
400
(347)
600
(521)
800
(694)
1000
(868)
Tightening time: sec.
(Steel plate thickness: t=3/8"(10 mm))
Tightening time: sec.
(Steel plate thickness: t=1"(25 mm))
200
(174)
400
(347)
600
(521)
800
(694)
1000
(868)
200
(174)
400
(347)
600
(521)
800
(694)
1000
(868)
•Model WH 9DM2
•Model WR 9DM2
Fig. 3-1
0123
kgf
.
cm
(in-lbs.)
5/16" x 1-3/6"
(M8 x 30)
Tightening torque
High-strength bolt
00
20
40
60
80
100
N
.
m
0123
kgf
.
cm
(in-lbs.) 3/8" x 1-3/6"
(M10 x 30)
Tightening torque
High-strength bolt
00
20
40
60
80
100
N
.
m
Ordinary bolt
0123
15/32" x 1-3/4"
(M12 x 45)
High-strength bolt
Ordinary bolt
kgf
.
cm
(in-lbs.)
Tightening torque
00
20
40
60
80
100
N
.
m
1200
(1042)
120
Tightening time: sec.
(Steel plate thickness:
t=3/8"(10 mm))
Tightening time: sec.
(Steel plate thickness:
t=1"(25 mm))
1400 140
200
(174)
400
(347)
600
(521)
800
(694)
1000
(868)
200
(174)
400
(347)
600
(521)
800
(694)
1000
(868)
200
(174)
400
(347)
600
(521)
800
(694)
1000
(868)
Tightening time: sec.
(Steel plate thickness: t=3/8"(10 mm))

--- 17 ---
6-4. Tightening Speed
Tightening speed comparison is shown below. The data below are intended for general reference only because
actual tightening speed may vary depending on ambient temperature, characteristics of battery, etc.
3 Wood screw 4.5 mm dia., 90 mm length, lauan
4 Wood screw 5.3 mm dia., 120 mm length, lauan
2 Wood screw 4.2 mm dia., 75 mm length, lauan
1 Wood screw 4.0 mm dia., 50 mm length, lauan
HITACHI WH 9DM2
HITACHI WH 9DM
C
1.5 sec.
Model sec.
1.3 sec.
2.0 sec.
12345
Fast Slow
2.7 sec.
Model sec.
2.3 sec.
3.5 sec.
12345
Fast Slow
4.6 sec.
Model sec.
4.0 sec.
6.3 sec.
Fast Slow
10.0 sec.
Model
9.2 sec.
15.0 sec.
12345678910
sec.
Fast Slow
246810 12 14 16 18 20
HITACHI WH 9DM2
HITACHI WH 9DM
C
HITACHI WH 9DM2
HITACHI WH 9DM
C
HITACHI WH 9DM2
HITACHI WH 9DM
C