Hitachi G 12SE2 Manual

TECHNICAL DATA
AND
SERVICE MANUAL
DISC GRINDER
G 12SE2
G 13SE2
SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT
LIST Nos. G 12SE2: E258
G 13SE2: E259 Revised Jul. 2003
G
MODELS G 12SE2
G 13SE2
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:
Symbols Utilized Competitors
Company Name Model Name
ATRAS COPCO AG13-125X
B BOSCH GWS9-125
Q

Page
CONTENTS
1. PRODUCT NAME...........................................................................................................................1
2. MARKETING OBJECTIVE .............................................................................................................1
3. APPLICATIONS..............................................................................................................................1
4. SELLING POINTS ..........................................................................................................................1
5. SPECIFICATIONS ..........................................................................................................................3
6. COMPARISONS WITH SIMILAR PRODUCTS ..............................................................................4
6-1. Specification Comparisons ............................................................................................................ 4
6-2. Comparisons in Torque vs. Rotation Speed and Stator Coil Temperature Rise ............................ 5
7. PRECAUTIONS IN SALES PROMOTION .....................................................................................6
7-1. Handling Instructions ..................................................................................................................... 6
7-2. Caution on Name Plate.................................................................................................................. 6
7-3. Precautions on Usage ................................................................................................................... 6
8. PRECAUTIONS IN DISASSEMBLY AND REASSEMBLY ............................................................7
8-1. Disassembly .................................................................................................................................. 7
8-2.Reassembly .................................................................................................................................... 9
8-3. Lubrication Points and Types of Lubricant................................................................................... 10
8-4. Tightening Torque ........................................................................................................................ 10
8-5. Wiring Diagrams ...........................................................................................................................11
8-6. Insulation Tests ............................................................................................................................ 12
8-7. No-load Current Value ................................................................................................................. 12
9. STANDARD REPAIR TIME (UNIT) SCHEDULES .......................................................................13
Assembly Diagram for G 12SE2
Assembly Diagram for G 13SE2

--- 1 ---
1. PRODUCT NAME
Hitachi Electric Disc Grinder, Model G 12SE2 [115 mm (4-1/2")]
Model G 13SE2 [125 mm (5")]
2. MARKETING OBJECTIVE
The current disc grinders Models G 12SE and G 13SE have obtained high evaluation in power, durability and
operability with the paddle switch. However, seven years passed since their development and now the
competitors are introducing high-power products to correspond to the market demand for compact and powerful
products. The new Models G 12SE2 and G 13SE2 are the upgraded versions of the current Models G 12SE and
G 13SE, featuring high power input (1200 W) to compete with the competitors.
Vigorous sales promotion and market share increases are anticipated with the introduction of the new Models
G 12SE2 and G 13SE2.
The key features of the Models G 12SE2 and G 13SE2 in comparison with the previous models are as follows:
1) Increased power input and maximum output
2) Increased overload durability
3) Increased wear resistance of the armature coil
3. APPLICATIONS
Deburring diecast products and finishing iron, bronze, aluminum and diecast products
Finishing welds and torch-cut surfaces
Cutting soft steel materials
Grooving and cutting concrete and other stone materials
4. SELLING POINTS
Wear resistance of armature coil:
2 times higher compared to the
current models
Easy-to-use large paddle switch
Class-top overload durability
1.1 times higher compared to Q
1.2 times higher compared to B
High power input : 1,200 W
G 12SE/G 13SE : 1,020 W
Q : 1,250 W
B : 900 W
Class-top
maximum output : 1,900 W
G 12SE/G 13SE : 1,550 W
Q : 1,540 W
B : 1,190 W

--- 2 ---
Class-top overload durability
The Models G 12SE2 and G 13SE2 provide class-top overload durability thanks to an improved cooling
mechanism and a high-power motor.
Practical test data: Comparison of torque when the stator coil temperature rise is 200˚ K
Fig. 2
Protect tape winding
Fig. 1
Wear resistance of armature coil
Fan side of the armature coil is sealed with protect tape and wedges at commutator side of the armature coil
are extended by 4 to 5.5 mm to minimize wear of the armature coil caused by dust.
The service life of the armature coil is 2 times longer than the conventional models as a result of the gravel
suction test (gravel is forcely sucked in through the vents of the tail cover).
100 50 0
Q
B
G 12SE2
G 13SE2
G 12SE
G 13SE
103
100
84
93
Fig. 3
4 mm to 5.5 mm
Wedge
Fig. 3
Paddle lever
Easy-to-use large paddle switch
Low-effort switch operation ensured by the use of a large paddle lever.
Gripping any part of the tail cover enables user to touch the switch.
(1) The switch, locked in position, can be turned off without changing the hand position.
(2) The grinder can be operated by gripping different parts of the tail cover, even without using the On-Lock
mechanism.
(Note: There is no On-Lock mechanism provided on models for some markets.)
Tail cover

--- 3 ---
Depressed-
center
wheels
5. SPECIFICATIONS
4,800 m/min (15,756 ft/min)
A, 36, Q, B
U.S.A., Canada: 5/8-11 UNC Other countries: M14 x 2
Dimensions
Model
Item
O.D. 115 mm (4-1/2")
x Thickness 6 mm (1/4")
x I.D. 22.2 mm (7/8")
O.D. 125 mm (5")
x Thickness 6 mm (1/4")
x I.D. 22.2 mm (7/8")
Max. practical
peripheral speed
Type
G 12SE2 G 13SE2
AC single phase 50 or 60 Hz
Power source
Paddle switch
1.9 kg (4.2 lbs.)
3.2 kg (7.1 lbs.) 3.3 kg (7.2 lbs.)
Corrugated cardboard box
No-load speed
Type of motor
Enclosure
Type of switch
Weight Net: *(main body)
Gross:
Type of packing
Standard accessories Depressed-center wheel
115 mm (4-1/2") ......................1
Side handle .............................1
Wrench....................................1
Voltage and power input
110, 120 V: 10,000/min 230, 240 V: 11,000/min
AC single phase commutator motor
Housing (Green)
Tail cover (Black)
Gear cover, packing gland ................ Aluminum alloy diecasting
........................Polyamide resin with glassfiber
Depressed-center wheel
125 mm (5") ............................1
Side handle .............................1
Wrench....................................1
○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○○
Voltage (V) Current (A) Power input (W)
110
230
120
1,050
1,200
1,080
10.0
5.5
9.5
* Net weight excludes cord, side handle, depressed-center wheel, wheel nut, wheel washer and wheel guard.
Spindle thread
Optional accessories Super washer (Code No. 310338)
240 1,200
5.3

--- 4 ---
125
(5")
900
570
1,130
11,000
87
150
1.8 (4.0 lbs.)
1.8 (4.0 lbs.)
298 (11-23/32")
70 (2-3/4")
HITACHI
G 12SE2
G 13SE2
115/125
(4-1/2"/5")
1,200
770
1,900
11,000
84
100
1.9 (4.2 lbs.)
2.1 (4.5 lbs.)
321 (12-5/8")
70 (2-3/4")
Maker
Model name
Capacity:
Depressed-center wheel dia. (mm)
Power input *1 (W)
Power output *1 (W)
Max. power output *1 (W)
No-load speed *1 (/min)
No-load sound pressure level (dB)
Service life of carbon brushes *2 (hr)
Weight *3 (kg)
(Actual weight) (kg)
Dimensions L (mm)
H (mm)
6. COMPARISONS WITH SIMILAR PRODUCTS
6-1. Specification Comparisons
G 12SE
G 13SE
115/125
(4-1/2"/5")
1,020
680
1,550
10,000
84
100
1.9 (4.2 lbs.)
2.1 (4.5 lbs.)
321 (12-5/8")
70 (2-3/4")
125
(5")
1,250
800
1,540
11,000
87
140
2.1 (4.5 lbs.)
2.1 (4.5 lbs.)
386 (15-13/64")
70 (2-3/4")
*1 Depends on market
*2 Service life of carbon brushes in the
continuous rated load test
*3 Weight without cord, side handle, depressed-
center wheel, wheel nut, wheel washer and
wheel guard
QB
L
H

--- 5 ---
6-2. Comparisons in Torque vs. Rotation Speed and Stator Coil Temperature Rise
Figure 4 shows comparisons of the rotation speed and the stator coil temperature rise between a competitive
model with respect to torque. Torque represents the magnitude of load, i.e., the amount of pressing force, cutting
depth and forward force in actual cutting jobs. This shows that a powerful motor is less likely to burn out because
it has both a minimum drop of rotation speed even at a greater torque and a lower stator coil temperature rise at
the same torque.
Fig. 4 Comparisons in torque vs. rotation speed and stator coil temperature rise
Load
Rotation speed of spindle (/min)
12,000
4,000
8,000
10,000
0
HITACHI G 12SE2/G 13SE2
HITACHI G 12SE2/G 13SE2
B
6,000
2,000
Rotation speed of spindle
HITACHI
G 12SE/G 13SE
Stator coil temp rise
Q
B
Q
HITACHI G 12SE/G 13SE
600
500
400
300
200
100
Stator coil temp rise (K)
Figure 4 indicates:
(1) The Models G 12SE2 and G 13SE2 keep higher rotation speed than the Models G 12SE/G 13SE, Q and B in
the heavy load range. This means that the working efficiency of the Models G 12SE2 and G 13SE2 is superior
to the Models G 12SE/G 13SE, Q and B.
(2) The stator coil temperature rise of the Models G 12SE2 and G 13SE2 is lower than that of the Models G 12SE/
G 13SE, Q and B. This means that the Models G 12SE2 and G 13SE2 are resistant to burn out even at a
heavy load operation and their motors are tough.

--- 6 ---
7. PRECAUTIONS IN SALES PROMOTION
In the interest of promoting the safest and most efficient use of the Models G 12SE2 and G 13SE2 Disc Grinders
by all of our customers, it is very important that at the time of sale, the salesperson carefully ensures that the
buyer seriously recognizes the importance of the contents of the Handling Instructions, and fully understands the
meaning of the precautions listed on the Name Plate or Caution Plate attached to each tool.
7-1. Handling Instructions
Although every effort is made in each step of design, manufacture and inspection to provide protection against
safety hazards, the dangers inherent in the use of any electric power tool cannot be completely eliminated.
Accordingly, general precautions and suggestions for the use of electric power tools, and specific precautions and
suggestions for the use of the disc grinders are listed in the Handling Instructions to enhance the safe and efficient
use of the tool by the customer. Salespersons must be thoroughly familiar with the contents of the Handling
Instructions to be able to offer appropriate guidance to the customer during sales promotion.
7-2. Caution on Name Plate
Each tool is provided with a Name Plate which contains the following basic safety precautions in the use of the
tool.
7-3. Precautions on Usage
Never press the pushing button while the depressed-center wheel is rotating.
If the pushing button is pressed while the depressed-center wheel is rotating, the spindle will stop immediately.
In such a case, there is a danger that the wheel nut may be loosened so that the depressed-center wheel flies off
unexpectedly to cause possible serious injury.
(3) For U.S.A. and Canada
CAUTION
Read thoroughly HANDLING INSTRUCTIONS before use.
(1) For European countries
(2) For New Zealand and Australia
*
*
*G 12SE2: 13,300
G 13SE2: 12,000

--- 7 ---
Fig. 5
8. PRECAUTIONS IN DISASSEMBLY AND REASSEMBLY
The [Bold] numbers in the descriptions below correspond to the numbers in the Parts List.
8-1. Disassembly
(1) Disassembly of the armature (Fig. 5)
1. Open the Lever [31], loosen the Machine Screw (W/Washers) M5 x 25 [32], and remove the Wheel Guard
Ass'y (Toolless Type) [35].
2. Loosen the two Tapping Screws (W/Flange) D4 x 35 [48] and the Tapping Screw (W/Flange) D4 x 20 [50], and
remove Tail Cover (A) [54] and Tail Cover (B) [47].
3. Remove the two Carbon Brushes [51] from the Brush Holders [52].
4. Remove the four Tapping Screws D5 x 25 [2]. The Armature [12] can then be taken out simultaneously with
the Gear Cover Ass'y [4], Packing Gland [25], and related parts.
5. Remove the four Seal Lock Screws (W/Sp. Washer) M5 x 16 [26].
The Packing Gland [25] can then be taken out together with the Spindle [28] and the Gear [20].
6. After removing the two Seal Lock Screws (W/Sp. Washer) M4 x 10 [1], the Armature [12] can be extracted
together with the Bearing Cover [11] and related parts.
7. Carefully wrap the Armature [12] with a soft, clean rag to protect it from being damaged, and clamp it securely
in a vise. Then, remove the Nut M8 [5] and extract the Pinion [6].
8. For the models indicated under Fig. 5, the Ball Bearing 629T12DDC3PS2-L [9] can be removed from the
Armature [12] by utilizing a J-204 Bearing Puller (special repair tool, Code No. 970982) as illustrated.
After the ball bearing has been removed, the Bearing Cover [11] can be easily taken off.
J204 Bearing Puller (Code No. 970982)