Hitachi DH 24DV Manual

TECHNICAL DATA
AND
SERVICE MANUAL
CORDLESS ROTARY HAMMER
DH 24DV
SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT
LIST No. G811 Jun. 2004
D
MODEL
DH 24DV
Hitachi 
Power Tools

Symbols Utilized
Competitors
Company Name Model Name
DEWALT DW004K
P
BOSCH GBH24V
B
MAKITA BHR200
C
Panasonic EZ6813
Q
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:

Page
CONTENTS
1. PRODUCT NAME .............................................................................................................................. 1
2. MARKETING OBJECTIVE ................................................................................................................ 1
3. APPLICATIONS ................................................................................................................................. 1
4. SELLING POINTS ............................................................................................................................. 2
4-1. Selling Point Descriptions ...................................................................................................................3
5. SPECIFICATIONS ............................................................................................................................. 5
5-1. Specifications ......................................................................................................................................5
5-2. Optional Accessories ..........................................................................................................................7
6. COMPARISONS WITH SIMILAR PRODUCTS ............................................................................... 12
6-1. Specification Comparisons ...............................................................................................................12
6-2. Drilling Speed Comparisons .............................................................................................................13
6-3. Per Charge Working Capacity Comparisons ....................................................................................14
7. PRECAUTIONS IN SALES PROMOTION ...................................................................................... 15
7-1. Handling Instructions ........................................................................................................................ 15
7-2. Caution Plates ..................................................................................................................................17
7-3. Precautions Requiring Particular Attention During Sales Promotion ................................................ 18
8. REFERENCE MATERIAL ................................................................................................................ 19
8-1. Lubrication ........................................................................................................................................19
8-2. Tool Structure ....................................................................................................................................19
8-3. "Rotation Only" and "Rotation + Striking" Changeover Mechanism ................................................. 22
8-4. "Rotation Only" (No striking) ............................................................................................................. 22
8-5. Drill Bits .............................................................................................................................................22
8-6. Tool Retainer Section ........................................................................................................................ 23
8-7. Dust Collector (B) .............................................................................................................................24
9. PRECAUTIONS IN DISASSEMBLY AND REASSEMBLY ............................................................. 25
9-1. Disassembly ..................................................................................................................................... 25
9-2. Reassembly ......................................................................................................................................28
9-3. Precautions on Disassembly and Reassembly of the Charger .........................................................30
10. STANDARD REPAIR TIME (UNIT) SCHEDULES ........................................................................ 31
Assembly Diagram for DH 24DV

--- 1 ---
1. PRODUCT NAME
Hitachi Cordless Rotary Hammer, Model DH 24DV
2. MARKETING OBJECTIVE
The Model DH 24DV is an upgraded version of the current Model DH 20DV. It features the fastest drilling speed
in the 24-V class thanks to the higher power motor and the more efficient transmission of the hammering force.
In addition, the cylindrical gear cover contributes to the reliable resistance to grease leakage and the powerful
design. The Model DH 24DV is more convenient than the current model thanks to the switchable hammering
force mechanism. The applicable battery is the Type EB 2420 or EB 2430HA. Each battery can be mounted and
removed easily as they are slide-type batteries. The main components of the hammering mechanism and the tool
retainer are common with the Model DH 24PB2.
3. APPLICATIONS
(1) Rotation and striking function
Drilling anchor holes
Drilling holes in concrete, tile, brick and similar materials
(2) Rotation only function
Drilling holes in steel and wood (with chuck adapter)
Tightening and loosening machine screws and wood screws (with chuck adapter)
[Typical applications]
Air conditioning ................................... Installation of air conditioners, water coolers and heaters, and air ducts
Piping and plumbing ........................... Installation of gas, water, and sanitary facilities
Electrical work ..................................... Installation of light fixtures and various electric appliances
Interior decoration ............................... Installation of seating, display stands and partitions
Other civil engineering, construction and repair work

--- 2 ---
4. SELLING POINTS
Fastest drilling speed in the 24-V class
Equivalent to Q
1.4 times faster than B, P, C and the Model DH 20DV
Switchable hammering force mechanism
increases working efficiency
POWER mode: For drilling holes in 5 mm or more diameter
Powerful and quick drilling
SAVE mode: For drilling holes in 4.8 mm or less diameter
Prevents the bit from being bent
Cylindrical gear cover
Increased in sturdiness and reliability
Powerful and advanced design
(B and C: Constructed of two parts)
Replaceable carbon brushes
The carbon brushes can be replaced by loosening
the two screws and removing the grip cover.
(B, P and Q: Not replaceable.)
One-push tool retainer eliminates
the need for sliding the grip
at mounting the bit.
Sliding the grip is required at removal
of the bit.
Comfortably shaped handle
It is well-balanced and easy to push
straight in either upward or horizontal
direction.

--- 3 ---
4-1. Selling Point Descriptions
4-1-1. Fastest drilling speed in the 24-V class
The drilling speed of the Model DH 24DV is equivalent to Q and 1.4 times higher than the Model DH 20DV, B, P
and C thanks to the efficient transmission of the hammering energy. For detail, refer to "6-2. Drilling Speed
Comparisons" on page 13.
4-1-2. Cylindrical gear cover
To avoid grease leakage, the Model DH 24DV is equipped with the cylindrical gear cover that is used for electric
rotary hammer drills instead of the current Model DH 20DV's two-part housing. In addition, the Model DH 24DV is
equipped with a sealed type bearing at the tip of the bearing unit in the gear cover to increase the resistance to
grease leakage.
4-1-3. Switchable hammering force mechanism increases working efficiency
The Model DH 24DV is equipped with the switchable hammering force mechanism to prevent small-diameter bits
(4.8 mm or less) from being bent. The hammering force can be adjusted by switching between "POWER" mode
and "SAVE" mode.
POWER (= Powerful mode) For drilling holes in 5 mm or more diameter speedily
SAVE (= Suppressing mode) For drilling holes in 4.8 mm or less diameter preventing the bit from being bent
The Model DH 24DV can also be used for drilling holes into soft workpieces by decreasing the hammering force.
Following figures show a comparison of the brick breakage when drilling holes into bricks as a guide of the
hammering force.
Drilling holes in 10 mm diameter
Drilling holes in 4.8 mm diameter
4-1-4. One-push tool retainer
The tool retainer of the current Model DH 20DV needs sliding the grip to mount the bit. The one-push tool
retainer of the Model DH 24DV eliminates the need for sliding the grip to mount the bit (sliding the grip is required
at removal of the bit).
4-1-5. Replaceable carbon brushes
The Model DH 24DV has the grip cover secured with two screws to the housing. By removing the grip cover, the
carbon brushes are exposed and they can be replaced with new ones. For detail, refer to "(7) Replacement of
the carbon brushes" on page 27. These carbon brushes are auto-stop type. When they become worn, the Model
DH 24DV automatically interrupts the current and stops. Instruct the customers to replace the carbon brushes
with new ones in this case.

--- 4 ---
4-1-6. Comfortably shaped handle
The handle is shaped so that it is easy to push the main body straight in either upward or horizontal direction.
The double-layer molded grip cover consists of a resin base covered with a soft resin to ensure a soft-touch and
non-slip grip of the handle.
Drilling
in horizontal direction
Drilling
in upward direction
It is easy to hold because this portion
reduces the massive feeling.
It is well balanced by holding
the rear of the motor.
B

--- 5 ---
Sealed power source: Single-phase AC, 50/60 Hz
Voltage: Depending on the order specification
Power input: 90 W
Charging system: Constant current charge with full wave phase control
Overcharge protection system: (1) Battery voltage detection ( 2V system)
for EB 2420 battery
Ni-MH battery temperature detection
(dT/dt system) for EB 2430HA battery
(2) Battery surface temperature detection
(thermistor)
(3) 120 minutes timer
Output voltage: DC 24V
Output current: 2.5 A
Charging time: Approx. 50 minutes (for EB 2420 at 20ûC (68ûF))
Approx. 70 minutes (for EB 2430HA at 20ûC (68ûF))
Operable ambient temperature range: 0ûC --- 40ûC (32ûF --- 104ûF)
The maximum allowable temperature of the Model 2420 battery is 60ûC
(140ûF) and the Model EB 2430HA battery is 45ûC (113ûF).
Weight
"POWER" mode: 4,500/min., "SAVE" mode: 2,200/min.
Main body 4.0 kg (8.8 lbs.) (with battery)
Battery EB 2420 1.3 kg (2.87 lbs.)
EB 2430HA 1.4 kg (3.09 lbs.)
Charger UC 24YFB 0.6 kg (1.3 lbs.)
Type of motor DC magnet motor
No-load rotation speed "POWER" mode: 1,000/min., "SAVE" mode: 500/min.
Type of switch Trigger switch with forward/reverse rotation selector (with brake)
D-type handle with side handle
Handle shape
5. SPECIFICATIONS
5-1. Specifications
Capacity
Usable drill bits
24 mm (15/16")
SDS-plus type only
13 mm (1/2")
30 mm (1-3/16")
Concrete
Steel
Wood
Full-load blow
Enclosure
Body Glassfiber reinforced polyamide resin ••••Housing, gear cover
Glassfiber reinforced polycarbonate resin and thermoplastic
elastomer •••••••••••••••••••••••••••••••••••••••••••• Grip cover
Aluminum alloy die casting ••••••••••••••••••• Inner cover
Battery Glassfiber reinforced polyamide resin
Charger ABS resin
Battery
(Type EB 2420)
Sealed cylindrical nickel cadmium storage battery
Nominal voltage: DC 24V
Nominal life: Charging/discharging approximately 1,000 cycles
(in the case of Model UC 24YFB)
Nominal capacity: 2.0 Ah
Battery
(Type EB 2430HA)
Sealed cylindrical nickel-metal hydride storage battery
Nominal voltage: DC 24V
Nominal life: Charging/discharging approximately 500 cycles
(in the case of Model UC 24YFB)
Nominal capacity: 3.0 Ah
Charger
(Model UC 24YFB)

--- 6 ---
Charger (depending on order specifications) ••••••••••••••••••••••••••••••••••••••••••••••••• 1 unit
Side handle •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 1 pc.
Plastic case •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 1 pc.
Depth gauge ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 1 pc.
Red pilot lamp
remains lit or flashes.
Green pilot lamp is lit.
Storage battery or
charger is faulty.
During charging
Prior to charging
Charging completed
High battery
temperature
Standard
accessories
Charging not
possible
Charging not possible
because storage battery
temperature is too high.
Blinks
Blinks
Lit
Lit
Flickers
0.5 sec. ON, 0.5 sec. OFF
0.5 sec. ON, 0.5 sec. OFF
Stays ON constantly
0.1 sec. ON, 0.1 sec. OFF
Stays ON constantly
Pilot lamp indications (UC 24YFB)

--- 7 ---
5-2. Optional Accessories
A. Drilling anchor holes (rotation + striking)
(1) Drill bit (slender shaft)
(1) Drill bit (taper shank)
Outer dia. (mm)
11 (7/16")
12.3 (31/64")
12.7 (1/2")
14.3 (9/16")
14.5 (73/128")
17.5 (11/16")
Code No.
944460
944461
993038
944462
944500
944463
(2) Taper shank adapter
Type Code No.
Morse taper
No. 1 303617
(3) Cotter
Code No.
944477
3.4 (1/8")
3.5 (9/64")
Outer dia. (mm) Effective length (mm)
45 (1-25/32")
45 (1-25/32")
(2) Adapter for slender shaft
(SDS-plus shank)
Drill bit (slender shaft)
90 (3-17/32")
90 (3-17/32")
Overall length (mm) Code No.
306369
306368
306370
Code No.
Adapter for slender shaft
Drill bit (slender shaft)
(1) Drill bit (taper shank) (2) Taper shank adapter
(SDS-plus shank)
Drill bit (taper shank)
21.5 (27/32") 944464 Morse taper No. 2 303618
(3) Cotter
Straight-shank bit for
impact drills
13 mm (1/2") hammer drill
chuck (SDS-plus shank)
13 mm hammer drill chuck
For drilling operations when using a straight shank bit for impact drilling with a hammer drill
Chuck wrench
303619
303620
Taper-shank adapter (A-taper or B-taper) is provided as an
optional accessory, but drill bit is not provided.
A-taper
B-taper
Code No.Part name
Chuck wrench
Rubber cap
Part name
303332
303334
303335
13 mm (1/2") hammer drill chuck
(including chuck wrench)
Code No.
Rubber cap