Hitachi WH 9DMR Manual

TECHNICAL DATA
AND
SERVICE MANUAL
CORDLESS IMPACT DRIVER
WH 9DMR
CORDLESS IMPACT WRENCH
WR 9DMR
SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT
LIST Nos. WH 9DMR: G819
WR 9DMR: G820
Mar. 2005
W
MODELS
WH 9DMR
WR 9DMR
Hitachi 
Power Tools
WH 9DMR WR 9DMR

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
PDEWALT DW050
WH 9DMR

Page
CONTENTS
1. PRODUCT NAME .............................................................................................................................. 1
2. MARKETING OBJECTIVE ................................................................................................................ 1
3. APPLICATIONS ................................................................................................................................. 1
4. STANDARD EQUIPMENT ................................................................................................................. 1
5. SELLING POINTS ............................................................................................................................. 2
5-1. Selling Point Descriptions ...................................................................................................................4
6. SPECIFICATIONS ............................................................................................................................. 6
6-1. Specifications ......................................................................................................................................6
6-2. Optional Accessories ..........................................................................................................................8
7. COMPARISONS WITH SIMILAR PRODUCTS ................................................................................11
7-1. Specification Comparisons (Cordless Impact Driver) ....................................................................... 11
7-2. Specification Comparisons (Cordless Impact Wrench) .................................................................... 12
7-3. Tightening Torque .............................................................................................................................13
7-4. Tightening Speed .............................................................................................................................. 16
7-5. Number of Screws or Bolts Driven ....................................................................................................17
8. PRECAUTIONS IN SALES PROMOTION ...................................................................................... 18
8-1. Safety Instructions ............................................................................................................................18
8-2. Tightening Torque Inspection Prior to Operation .............................................................................. 20
8-3. Tightening Torque Variation ..............................................................................................................21
8-4. Suggestions and Precautions for the Efficient Use of the Charger ...................................................22
9. OTHER PRECAUTIONS ................................................................................................................. 23
10. REPAIR GUIDE ............................................................................................................................. 24
10-1. Precautions in Disassembly and Reassembly ................................................................................24
10-2. Precautions in Disassembly and Reassembly of Battery Charger ................................................. 33
11. STANDARD REPAIR TIME (UNIT) SCHEDULES......................................................................... 34
Model WH 9DMR .....................................................................................................................................34
Model WR 9DMR .....................................................................................................................................35
Assembly Diagram for WH 9DMR
Assembly Diagram for WR 9DMR

--- 1 ---
1. PRODUCT NAME
Hitachi Cordless Impact Driver, Model WH 9DMR
Hitachi Cordless Impact Wrench, Model WR 9DMR
2. MARKETING OBJECTIVE
The current Model WH 12DM2, developed under the concept for a "more compact, powerful and convenient
model", has been highly evaluated. However, the market is becoming fiercely competitive due to a price war of
the 9.6-V, 12-V, 14.4-V and 18-V impact driver/wrench series. To address the severe situation, we have
developed the new high-performance impact driver/wrench series Models WH 9DMR and WR 9DMR under the
same concept as the current impact driver/wrench series. The new Models WH 9DMR and WR 9DMR can take
on the low-price competitors.
The performance level is superior to the current Model WH 9DM2 and the competitors.
The cost is reduced by adoption of the new magnet and the like.
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.
4. STANDARD EQUIPMENT
(1) 2BGK specification: Two EB 9B batteries (NiCad, capacity 2.0 Ah), UC 18YG charger and case
(2) 2HFK specification: Two EB 926H or EB 930H batteries (NiMH, capacity 2.6 Ah or 3.0 Ah), UC 14YFA charger
and case

--- 2 ---
5. SELLING POINTS
(1) Cordless impact driver Model WH 9DMR
Class-top tightening speed and
tightening torque 105 N.m
P: 102 N.m
High durability, dust resistance
and long service life
Common to the Model WH 12DM2
Advanced case
Replaceable carbon brushes
Common to the Model WH 12DM2
Convenient light equipped hook
Common to the Model WH 12DM2
Protector is standard.
Common to the Model WH 12DM2
Common to the Model WH 12DM2

--- 3 ---
(2) Cordless impact wrench Model WR 9DMR
Class-top tightening torque 115 N•m
Class-top short body 160 mm and lightweight 1.4 kg
High durability, dust resistance
and long service life
Common to the Model WH 12DM2
Replaceable carbon brushes
Common to the Model WH 12DM2
Convenient light equipped hook
Common to the Model WH 12DM2
Protector is standard.
Common to the Model WH 12DM2
Advanced case
Common to the Model WH 12DM2

--- 4 ---
HITACHI WH 9DMR
HITACHI WH 9DM2
3.3 sec.
Model (sec.)
4.6 sec.
3.3 sec.
612
814
4
210
Fast Slow
P
16
* Tightening time may vary depending on hardness of the workpiece, ambient temperature, characteristics
of the battery, etc.
Selling points of the Model WH 9DMR
Top class tightening speed and tightening torque 105 N.m (1070 kgf.cm, 930 in-lbs.)
Although the Model WH 9DMR is equipped with an anisotropic bonded magnet that is cheaper than that of the
Model WH 9DM2, the performance is superior to the Model WH 9DM2 thanks to the large hammer and the
optimized impact timing. Comparison of measured data with the Model WH 9DM2 and competitors is shown
below.
Tightening time comparison
Figure 1 shows the time required for tightening a wood screw (4.5 mm dia. x 90 mm length) into a lauan
workpiece. (40% shorter than the Model WH 9DM2 and equivalent to P).
109
40
80
160
0
WH 9DMR WH 9DM2
400 (347 in-lbs.)
800 (694 in-lbs.)
1200 (1042 in-lbs.)
N
.
m
120
1600 (1389 in-lbs.)
82
105
140
100
60
200 (174 in-lbs.)
1000 (868 in-lbs.)
600 (521 in-lbs.)
1400 (1215 in-lbs.)
kgf
.
cm
20
P
Tightening torque
1
Fig. 1 Tightening time comparison
Tightening torque comparison
Figure 2 shows the torque required for
tightening an M12 high-strength tension
bolt in 3 seconds with a hexagon socket
(40 mm long) (33% higher than
WH 9DM2 and 4% higher than P).
2
Fig. 2 Tightening torque comparison
5-1. Selling Point Descriptions
Refer to pages 4 though 10 of Technical Data Service Manual for the Models WH 9DMR/WR 9DMR for common
selling points.
Model WR 9DMR
(1) Class-top tightening torque 115 N•m (1170 kgf•cm, 1020 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 tightening torque of
the Model WR 9DMR is equivalent to the current Model
WR 9DM2. (3 % lower than the Model WR 9DM2.)
122 118
160
140
120
100
80
60
40
20
0
WR 9DM2 WR 9DMR
Tightening torque
(N.m)

--- 5 ---
Product Unit
mm
Center height mm
Height mm
Overall length
Measured value kg
kgCatalog value
Weight
Hitachi
WR 9DMR
160 (6-19/64")
26.5 (1-3/64")
223 (8-25/32")
1.4 (3 lbs.)
1.43 (3.1 lbs.)
(2) Compact
The overall length of the Model WR 9DMR is equivalent to the current Model WR 9DM2.
Cordless impact wrench: Model WR 9DMR
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.)

--- 6 ---
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 type EB 9B battery at 20 ûC)
Approx. 60 minutes (for type EB 926H battery at 20 ûC)
Approx. 70 minutes (for type EB 930H battery at 20 ûC)
Product weight: 0.6 kg
Operable ambient temperature range: 0 ûC --- 40 ûC
The maximum allowable temperature of the EB 9B type battery is 55ûC and the
EB 926HL or EB 930H type battery is 45 ûC.
Charger (For UC 14YFA)
Sealed cylindrical nickel-cadmium batteries
Nominal voltage: DC 9.6 V
Nominal life: Charging/discharging approximately 300 cycles (in the case of Model
UC 18YG)
Nominal capacity: 2.0 Ah
6. SPECIFICATIONS
6-1. Specifications
Model Cordless impact driver
WH 9DMR
Capacity
Item
Cordless impact wrench
WR 9DMR
Small screw M4 --- M8 (5/32" --- 5/16")*1
Ordinary bolt M5 --- M12 (3/16" --- 15/32")
High-strength bolt M5 --- M10 (3/16" --- 25/64")
Ordinary bolt M6 --- M14 (1/4" --- 9/16")
High-strength bolt M6 --- M10 (1/4" --- 3/8")
Tightening torque 105 N•m (1070 kgf •cm, 930 in-lbs.)*2115 N•m (1170 kgf •cm, 1020 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 --- 2,600 /min
Impact rate 0 --- 3,200 /min
Main body 1.4 kg (3.0 lbs.)
Battery 0.55 kg (1.2 lbs.)
Overall length x height 155 mm (6-7/64") x 223 mm (8-25/32")
Center height 26.5 mm (1-3/64")
Battery (Type EB 9B)
160 mm (6-19/64") x 223 mm (8-25/32")
Battery (Type EB 926H/
EB 930H)
Sealed cylindrical nickel-metal hydride batteries
Nominal voltage: DC 9.6 V
Nominal life: Charging/discharging approximately 500 cycles (in the case of Model
UC 14YFA)
Nominal capacity: 2.6 Ah/3.0 Ah
Weight

--- 7 ---
Overcharge prevention circuit:
A thermostat monitors the surface temperature of the battery and, on detecting the
temperature rise which occurs on completion of charging, automatically turns off the
unit to prevent the battery from overcharge.
Input capacity: 70 W
Indication method: Pilot lamp indicator of battery charging
Function: On ••••••••••••••••••••••••••••••••••• During charging
Off ••••••••••••••••••••••••••••••••••• Charging completed
*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 (Model UC 18YG)
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 (Model 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.
NOTE: The Model UC 18YG
charger is exclusive to
NiCad batteries.

--- 8 ---
6-2. Optional Accessories
(1) Optional accessories for the Model WH 9DMR
•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.

--- 9 ---
(2) Optional accessories for the Model WR 9DMR
•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
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 LL
1
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
φ
φ
φ
φ
Shape B Shape D
Shape C Sq

--- 10 ---
•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

--- 11 ---
7. COMPARISONS WITH SIMILAR PRODUCTS
7-1. Specification Comparisons (Cordless Impact Driver)
HITACHI
WH 9DMR
Maker
Model
Item
Catalog specifications
Capacity
M 4 --- M 8
(5/32" --- 5/16")
Small screw
M 5 --- M 12
(3/16" --- 15/32")
Ordinary bolt
80
(820 kgf•cm, 710 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
109
(1110 kgf•cm, 965 in-lbs.)
Max. tightening torque N•m
Measured figures
0 --- 2,550
No-load rotation speed /min
0 --- 3,100
Impact rate /min
155 x 223
(6-7/64" 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, EB 926H or EB 930H
Battery
V
A
Type
EB 9B: 2.0
EB 926H: 2.6
EB 930H: 3.0
Nominal capacity Ah
9.6
Nominal voltage V
Ambient temperature
ûC
UC 14YFA or UC 18YG
Model
UC 14YFA: 56
UC 18YG: 70
Power input capacity
VA
UC 14YFA: 7.2 --- 14.4
UC 18YG: 7.2 --- 18
Recharging voltage
V
Plastic tool case
Charger (UC 14YFA
or UC 18YG)
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 and hook (hexagon bit etc.).
*2
*3
*2
*2
WH 9DM2
M 4 --- M 8
(5/32" --- 5/16")
M 5 --- M 12
(3/16" --- 15/32")
105
(1070 kgf•cm, 930 in-lbs.)
0 --- 2,800
0 --- 3,200
1.2 (2.6 lbs.)
82
(835 kgf•cm, 725 in-lbs.)
0 --- 2,570
0 --- 3,190
147 x 223
(5-25/32" x 8-25/32")
26.5 (1-3/64")
1.29 (2.8 lbs.)
70
Trigger switch with
forward/reverse
changeover pushing
button with brake and
variable
DC magnet
9.6
21
EB 9B or EB 930H
EB 9B: 2.0
EB 930H: 3.0
9.6
0 --- 40
UC 14YF2 or UC 14YFA
44 or 56
7.2 --- 14.4
Plastic tool case
Charger (UC 14YF2
or UC 14YFA)
Driver chuck
Tool tip mounting system Driver chuck
0 --- 2,400
0 --- 3,000
1.59 (3.5 lbs.)
105
(1070 kgf•cm, 930 in-lbs.)
0 --- 2,450
29 (1-9/64")
1.57 (3.5 lbs.)
70
Trigger switch with
forward/reverse
changeover pushing
button with brake and
variable
DC magnet
9.6
28
DW 9061
9.6
---
DW 9107
---
7.2 --- 14.4
Driver chuck
P
101.7
(1035 kgf•cm, 900 in-lbs.)
165 x 233
(6-1/2" x 9-11/64")
1.7
Plastic tool case
Charger
M 5 --- M 10
(3/16" --- 3/8")
High-strength bolt M 5 --- M 10
(3/16" --- 3/8")
0 --- 40
*1*1
0 --- 2,810

--- 12 ---
7-2. Specification Comparisons (Cordless Impact Wrench)
HITACHI
WR 9DMR
Maker
Model
Item
Catalog specifications
Capacity
M 6 --- M 14
(1/4" --- 9/16")
Ordinary bolt
120
(1220 kgf•cm, 1060 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
118
(1200 kgf•cm, 1045 in-lbs.)
Max. tightening torque N•m
Measured figures
0 --- 2,550
No-load rotation speed /min
0 --- 3,440
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
29
Current
EB 9B, EB 926H or EB 930H
Battery
V
A
Type
EB 9B: 2.0
EB 926H: 2.6
EB 930H: 3.0
Nominal capacity Ah
9.6
Nominal voltage V
Ambient temperature
ûC
UC 14YFA or UC 18YG
Model
UC 14YFA: 56
UC 18YG: 70
Power input capacity
VA
UC 14YFA: 7.2 --- 14.4
UC 18YG: 7.2 --- 18
Recharging voltage
V
Plastic tool case
Charger (UC 14YFA
or UC 18YG)
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 and hook (hexagon bit etc.).
*1
*2
*1
*2
WR 9DM2
M 6 --- M 14
(1/4 --- 9/16")
115
(1170 kgf•cm, 1020 in-lbs.)
0 --- 2,600
0 --- 3,200
1.4 (3.0 lbs.)
122
(1240 kgf•cm, 1076 in-lbs.)
0 --- 2,460
0 --- 3,230
160 x 223
(6-19/64" x 8-25/32")
26.5 (1-3/64")
1.43 (3.1 lbs.)
70
Trigger switch with
forward/reverse
changeover pushing
button with brake and
variable
DC magnet
9.6
27
EB 9B or EB 930H
EB 9B: 2.0
EB 930H: 3.0
9.6
0 --- 40
UC 14YF2 or UC 14YFA
44 or 56
7.2 --- 14.4
Plastic tool case
Charger (UC 14YF2
or UC 14YFA)
Retaining ringTool tip mounting system Retaining ring
M 6 --- M 10
(1/4" --- 3/8")
High-strength bolt M 6 --- M 10
(1/4" --- 3/8")
0 --- 40
9.5 mm (3/8") square drive
Tip condition
9.5 mm (3/8") square drive

--- 13 ---
PWH 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
1200
(1042 in-lbs.)
N.m
120
100
80
20
40
60
0
0
(sec.)
WH 9DMR
7-3. Tightening Torque
7-3-1. Tightening torque characteristic comparisons
(1) Impact driver
Fig. 3-1
Fig. 3-2
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
WR 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
WR 9DMR
1200
(1042 in-lbs.)
N
.
m
120
100
80
20
40
60
0
0
(sec.)
140
0
1400
(1215 in-lbs.)

--- 14 ---
7-3-2. 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. 4 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. 4
Table 1
Table 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

--- 15 ---
7-3-3. Bolt tightening torque characteristics
Figures 5-1 and 5-2 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. 5-1 and 5-2, 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. 5-2
Bolt
Nut
Steel plate
thickness: t
* The following bolts were utilized:
Ordinary bolt; strength grade 4.8
High-strength bolt; strength 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)
•Model WH 9DMR
•Model WR 9DMR
Fig. 5-1
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)
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
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))
Ordinary bolt

--- 16 ---
HITACHI WH 9DMR
HITACHI WH 9DM2
P
1.2 sec.
Model sec.
1.5 sec.
1.2 sec.
12345
Fast Slow
Model sec.
2.7 sec.
2.1 sec.
123
2.1 sec.
45
Fast Slow
3.3 sec.
Model sec.
4.6 sec.
3.3 sec.
Fast Slow
123456789
10
HITACHI WH 9DMR
HITACHI WH 9DM2
P
HITACHI WH 9DMR
HITACHI WH 9DM2
P
7-4. 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
2 Wood screw 4.2 mm dia., 75 mm length, lauan
1 Wood screw 4.0 mm dia., 50 mm length, lauan

--- 17 ---
7-5. Number of Screws or Bolts Driven
Comparison data on the number of screws which can be tightened per battery charge are shown in the table
below. Please note that the data below are intended for general reference only as the number of screws which
can be tightened per charge may vary depending on tightening conditions, screw sizes, ambient temperature,
characteristics of battery, etc.
(1) Screws (Cordless impact driver: Model WH 9DMR)
Battery
Tightening condition
Model P
DW 9061
(Battery capacity: 1.7 Ah)
Wood screw
4.0 mm dia. and 50 mm length
Workpiece: Cedar, no prepared hole
260
690Machine screw M8 x 16L
(2) Ordinary bolts (Cordless impact wrench: Model WR 9DMR)
Comparison data on the number of bolts which can be tightened per battery charge are shown in the table
below. Please note that the data below are intended for general reference only as the number of bolts which
can be tightened per charge may vary depending on tightening conditions, bolt sizes, ambient temperature,
characteristics of battery, etc.
Battery
Tightening condition
Model
Coach bolt 9 x 90
Prepared hole
6.5 mm dia. and
90 mm depth
Number of bolts
Time (sec.)
HITACHI
WH 9DMR
EB 9B
(Battery capacity: 2.0 Ah)
260
690
HITACHI
WH 9DM2
EB 9B
(Battery capacity: 2.0 Ah)
233
753
HITACHI
WR 9DMR
EB 9B
(Battery capacity: 2.0 Ah)
27
15.4
HITACHI
WR 9DM2
EB 9B
(Battery capacity: 2.0 Ah)
29
13.4