Hitachi WH 12DAF Manual

POWER TOOLS
TECHNICAL DATA
AND
SERVICE MANUAL
CORDLESS IMPACT DRIVER
WH 12DAF
SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT
LIST No. F880 Feb. 2003
W
MODEL
WH 12DAF

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
C MAKITA 6914D
P DeWALT DW977K

Page
CONTENTS
1. PRODUCT NAME............................................................................................................................. 1
2. MARKETING OBJECTIVE ............................................................................................................... 1
3. APPLICATIONS................................................................................................................................ 1
4. SELLING POINTS ............................................................................................................................ 2
4-1. Selling Point Descriptions ................................................................................................................. 2
5. SPECIFICATIONS ............................................................................................................................ 3
5-1. Specifications.....................................................................................................................................3
5-2. Optional Accessories .........................................................................................................................5
6. COMPARISONS WITH SIMILAR PRODUCTS ................................................................................ 6
6-1. Specification Comparisons ................................................................................................................6
6-2. Tightening Torque ..............................................................................................................................7
6-3. Number of Screws or Bolts Driven.....................................................................................................9
7. PRECAUTIONS IN SALES PROMOTION ..................................................................................... 10
7-1. Safety Instructions ...........................................................................................................................10
7-2. Tightening Torque Inspection Prior to Operation .............................................................................12
7-3. Tightening Torque Variation .............................................................................................................12
7-4. Suggestions and Precautions for the Efficient Use of the Charger and Storage Batteries..............14
8. OTHER PRECAUTIONS ................................................................................................................ 14
9. REPAIR GUIDE .............................................................................................................................. 15
9-1. Precautions in Disassembly and Reassembly.................................................................................15
9-2. Precautions in Disassembly and Reassembly of Battery Charger ..................................................21
10. STANDARD REPAIR TIME (UNIT) SCHEDULES ....................................................................... 22
Assembly Diagram for WH 12DAF

--- 1 ---
1. PRODUCT NAME
Hitachi Cordless Impact Driver, Model WH 12DAF
2. MARKETING OBJECTIVE
The current high-grade Model WH 12DM is obtaining high evaluation in the cordless impact driver market that is
expanding especially in Europe. The new Model WH 12DAF is a popular version that provides an excellent cost/
performance ratio, inheriting the well-reputed features of the Model WH 12DM such as soft grip and belt hook.
Vigorous sales promotion is anticipated with the introduction of the new Model WH 12DAF ahead of the
competitors.
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
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 aids, automobile repair, assembly of garages
and carports storage sheds, etc.
Various other assembly, construction or repair facilities

--- 2 ---
4. SELLING POINTS
Soft-grip handle
Convenient belt hook
Variable speed reversible
switch with electric brake
Max. torque 88 N•m
(780 in-lbs.)
4-1. Selling Point Descriptions
(1) Max. torque 88 N•m (780 in-lbs)
The maximum torque of the Model WH 12DAF is 88 N•m (780 in-lbs.) thanks to the optimum striking design
while maintaining high mechanical strength with the durable die-casting aluminum hammer case, etc.
(2) Soft-grip handle
The grip of the Model WH 12DAF is soft, slip-resistant and comfortable thanks to the soft resin (elastomer)
covered on the handle.
(3) Convenient belt hook
A hook is very convenient if there is no place to put the impact driver temporarily. Although various kinds of
hooks are on the market, there is a user demand for a standard accessory hook. To cope with this demand,
the Model WH 12DAF is equipped with the hook having the following features as a standard accessory.
The hook can be quickly slide out and can be slide in when not needed.
The hook is mountable on either side to cope with the use by either right-handed persons and left-handed
persons. The mounting position can be changed by using a flat-blade screwdriver or a coin.
The angle of the hook is adjustable in five steps (0, 20, 40, 60 and 80˚). The hook can be adjusted to the
optimum position according to the weight of the bit in use.
Durable die-casting aluminum hammer case

--- 3 ---
5. SPECIFICATIONS
5-1. Specifications
Capacity Small screw M4 --- M8 (5/32" --- 5/16")*1
Ordinary bolt M4 --- M12 (5/32" --- 15/32")
High-strength bolt M4 --- M10 (5/32" --- 3/8")
Tightening torque 88 N•m (900 kgf•cm, 780 in-lbs.)*2
Tip condition 6.35 mm (1/4") bit holder
Type of motor Fan cooled DC magnet motor
Enclosure Body ••••••••••••Glassfiber reinforced polyamide resin (green)
and themoplastic elastomer (charcoal gray)
Aluminum alloy die casting •••••••••••••••••••••••••••••••••••• Hammer case
Battery •••••••• ABS resin (black)
Charger •••••• ABS resin (black)
Type of switch
Trigger switch with push button for forward and reverse rotation changeover (with brake)
Handle configuration T-type
No-load rotation speed 0 --- 2,200/min
Impact rate 0 --- 2,900/min
Main body 1.6 kg (3.5 lbs.) (with battery EB 1214L/EB 1220BL/EB 1222HL)
1.5 kg (3.3 lbs.) (with battery EB 1212S)
Battery 0.6 kg (1.3 lbs.) (with battery EB 1214L/EB 1220BL/EB 1222HL)
0.5 kg (1.1 lbs.) (with battery EB 1212S)
Overall length x height 176 mm (6-15/16") x 226 mm (8-7/8") (with battery EB 1214L/EB 1220BL/EB 1222HL)
176 mm (6-15/16") x 217 mm (8-1/2") (with battery EB 1212S)
Center height 26 mm (1-1/64")
Battery
(Type EB 1212S/
EB 1214L)
Sealed cylindrical nickel-cadmium battery
Nominal voltage •••••••• DC 12V
Nominal life •••••••••••••• Charging/discharging: approximately 300/500 times
(in case of Model UC 12SD or UC 24YFA)
Nominal capacity ••••••• 1.2 Ah/1.4 Ah
Weight
•••••• Housing
Battery
(Type EB 1220BL) Sealed cylindrical nickel-cadmium battery
Nominal voltage •••••••• DC 12V
Nominal life •••••••••••••• Charging/discharging: approximately 1,000 times
(in case of Model UC 24YFA)
Nominal capacity ••••••• 2.0 Ah
Battery
(Type EB 1222HL) Sealed cylindrical nickel-metal hydride battery
Nominal voltage •••••••• DC 12V
Nominal life •••••••••••••• Charging/discharging: approximately 500 times
(in case of Model UC 24YFA)
Nominal capacity ••••••• 2.2 Ah

--- 4 ---
*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 sec. with a hexagon socket.
Overcharge prevention circuit:
A thermostat monitors the surface temperature of the battery and on detecting the
temperature rise which occur on completion of charging, automatically turns off the
unit to prevent the battery from overcharge.
Input capacity: 51 W
Indication method: Pilot lamp indicator of battery charging
Function: On •••••••••••••••••• During charging
Off •••••••••••••••••• Charging completed
Charger
(Model UC 12SD)
Overcharge protection system: (1) Battery voltage detection ( 2V system)
(2) Battery surface temperature detection
(thermostat or thermistor)
(3) 120-minute timer
Input capacity: 90 W
Charging time:
Approx. 40 minutes [for type EB 1212S/EB 1214L battery at 20˚C (68˚F)]
Approx. 50 minutes [for type EB 1220BL battery at 20˚C (68˚F)]
Approx. 55 minutes [for type EB 1222HL battery at 20˚C (68˚F)]
Operable ambient temperature range: 0˚C --- 40˚C (32˚F --- 104˚F)
The maximum allowable temperature of the type EB 1212S, EB 1214L and EB 1220BL
battery is 60˚C (140˚F) and the type EB 1222HL battery is 45˚C (113˚F).
Charger
(Model UC 24YFA)
Weight Net Main body (with battery EB 1214L/EB 1220BL/EB 1222HL) ••••••••••••• 1.6 kg (3.5 lbs.)
(with battery EB 1212S) ••••••••••••••••••••••••••••••••••••••••••••••••• 1.5 kg (3.3 lbs.)
Charger unit (UC 12SD) (including cord) ••••••••••••••••••••••••••••••••••••••••• 1.4 kg (3.1 lbs.)
Charger unit (UC 24YFA) (including cord) ••••••••••••••••••••••••••••••••••••••• 0.6 kg (1.3 lbs.)
Gross WH 12DAF (SSK) (with extra battery) •••••••••••••••••••••••••••••••••••••••••••• 5.1 kg (11.3 lbs.)
WH 12DAF (SSK) •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 4.6 kg (10.2 lbs.)
WH 12DAF (SLSK) (with extra battery) •••••••••••••••••••••••••••••••••••••••••• 5.3 kg (11.7 lbs.)
WH 12DAF (SLSK) •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 4.7 kg (10.4 lbs.)
WH 12DAF (BLFK) (with extra battery) •••••••••••••••••••••••••••••••••••••••••• 4.5 kg ( 9.9 lbs.)
WH 12DAF (HLFK) •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 3.9 kg ( 8.6 lbs.)
Standard accessories
SSK (with extra battery)
SSK
SLSK (with extra battery)
SLSK
BLFK (with extra battery)
HLFK
Charger
UC 12SD x 1
UC 12SD x 1
UC 12SD x 1
UC 12SD x 1
UC 24YFA x 1
UC 24YFA x 1
Battery
EB 1212S x 2
EB 1212S x 1
EB 1214L x 2
EB 1214L x 1
EB 1220BL x 2
EB 1222HL x 1
Case
x 1
x 1
x 1
x 1
x 1
x 1

--- 5 ---
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 24YFA)
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.
5-2. Optional Accessories
(1) Optional accessories
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")
9926897 (1/4")65 (2-9/16")74 mm Hexagon socket
Drill chuck adaptor set (Code No. 321823)
The drill chuck adaptor set permits mounting of various types
of locally-available drill bits for a variety of drilling operations.

--- 6 ---
EB 1220BL
•••••• Approx. -/50 min.
6. COMPARISONS WITH SIMILAR PRODUCTS
6-1. Specification Comparisons
M4 --- M8 (5/32" --- 5/16")
HITACHI
WH 12DAF
Maker
Model
Item
Capacity Small screw
M4 --- M12 (5/32" --- 15/32") Ordinary bolt
M4 --- M10 (5/32" --- 3/8")High-strength bolt
88
(780 in-lbs., 900 kgf•cm)
Max. tightening torque N•m
0 --- 2,200
No-load rotation speed /min
0 --- 2,900
Impact rate /min
Main body weight kg
Overall length mm 176 (6-15/16")
Center height mm
Equipped
Driver chuckTool tip mounting system
Switch
DC magnet
Type of motor
12
Voltage
1.2/1.4/2.0/2.2
12
Battery
V
Type EB 1212S/EB1214L/
EB 1220BL/EB 1222HL
Nominal capacity Ah
UC 12SD/UC 24YFA
Nominal voltage V
EB 1212S, EB 1214L
•••••• Approx. 60/40min.
Model
min. 12/7.2 --- 24
Recharging voltage V
Plastic case
Charger
(UC 12SD/UC 24YFA)
Standard accessories
Charger
*2
*3
*4
Overall height mm
26 (1-1/64")
1.6 (3.5 lbs.)
: With EB 1214L/
EB 1220BL/
EB 1222HL
1.5 (3.3 lbs.)
: With EB 1212S
226 (8-7/8")
: With EB 1214L/
EB 1220BL/
EB 1222HL
217 (8-1/2")
: With EB 1212S
Variable speed
Electric brake Equipped
Charging time
EB 1222HL
•••••• Approx. -/55 min.
*1
*1: In the case of tapping screws and wood screws, a minimum of M3 is possible.
*2: Max. tightening torque is based on tightening an M12 (15/32") bolt (strength grade: 12.9) for 3 sec. with a hexagon socket.
*3: Main body weight does not include accessory tools (hexagon bit, etc.).
*4: This types of battery could not charge by Model UC 12SD.
M4 --- M8 (5/32" --- 5/16")
M5 --- M12 (3/16" --- 15/32")
M5 --- M10 (3/16" --- 3/8")
100(885 in-lbs.,
1020 kgf•cm)
0 --- 2,300
0 --- 3,000
167 (6-37/64")
Equipped
Driver chuck
DC magnet
12
2.0/3.0
12
EB 1220BL/EB 1230HL
UC 14YF2
EB 1220BL
••••••• Approx. 60 min.
7.2 --- 14.4
Plastic case
Charger (UC 14YF2)
26 (1-1/64")
1.6 (3.5 lbs.)
226 (8-7/8")
Equipped
EB 1230HLL
••••••• Approx. 90 min.
*1
WH 12DM
M4 --- M8 (5/32" --- 5/16")
M5 --- M12 (3/16" --- 15/32")
M5 --- M10 (3/16" --- 3/8")
98 (870 in-lbs.,
1,000 kgf•cm)
0 --- 2,200
0 --- 3,000
176 (6-15/16")
Equipped
Driver chuck
DC magnet
12
2.0
12
1222
DC 1411
60 min.
7.2 --- 14.4
Plastic case
Charger
26 (1-1/64")
1.7 (3.8 lbs.)
232 (9-1/8")
Equipped
96 (850 in-lbs.,
978 kgf•cm)
0 --- 2,000
0 --- 2,600
220 (8-21/32")
Equipped
Driver chuck
DC magnet
12
1.7
12
DW9071
DW9107
60 min.
7.2 --- 14.4
Plastic case
Charger
42 (1-21/32")
2.1 (4.6 lbs.)
241 (9-1/2")
Equipped
CP
*4

--- 7 ---
6-2. Tightening Torque
6-2-1. 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. 1 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)
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)
K: Torque coefficient (0.17)
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. 1
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
05
(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