Hitachi G18ST User manual

REPAIR GUIDE ----------------------------------------------------------------------------------------------------------------1
1. Precautions on disassembly and reassembly -----------------------------------------------------------1
STANDARD REPAIR TIME (UNIT) SCHEDULES --------------------------------------------------------------------8
LIST Nos.
G 18ST: F227
G 18SW2: F228
G 23ST: F229
G 23SW2: F230
Dec. 2014
PRODUCT NAME
Hitachi 180 mm Disc Grinder
Models G 18ST, G 18SW2
Hitachi 230 mm Disc Grinder
Models G 23ST, G 23SW2
International Sales Division
G
CONTENTS
G 23ST

-1-
Fig. 1
WARNING: Before attempting disassembly or reassembly, be sure to turn off the power switch and
disconnect the plug from the power source outlet.
1. Precautions on disassembly and reassembly
The [Bold] numbers in the descriptions below correspond to the numbers in the Parts List and the
exploded assembly diagram for the Models G 18ST, G 18SW2, G 23ST, and G 23SW2.
1. Removal of the armature
(1) Loosen the Wheel Nut [27] and remove the wheel and Wheel Washer (C) [26].
(2) Loosen the Bolt M8 x 25 [24] and remove the Wheel Guard Ass’y [25].
Disassembly
REPAIR GUIDE
Wheel
[24]
[25]
[26]
[27]

-2-
Fig. 3
Fig. 2
(3) Loosen the Tapping Screws D4 x 16 [38] and remove the Brush Cover [37]. Then take out the Carbon
Brushes (1 Pair) [36].
(4) Remove the four Tapping Screws D5 x 35 [1]. The Armature [12] can then be taken out together with
the Gear Cover Ass'y [4], Packing Gland [22] and related parts as shown in Fig. 3.
(5) Loosen the four Bolts M5 x 16 [23]. Remove the Packing Gland [22] and related parts.
(6) Remove the Special Nut M10 [6] and extract the pinion of the Gear and Pinion Set [29].
(7) Carefully extract the Armature [12] from the Gear Cover Ass'y [4].
[12]
[1]
[4]
[22]
[23]
[6]
Pinion
[29]
[31]
[7]
[8]
[9]
[10]
[11]
[32]
[38]
[37]
[37]
[38]
[36]
[36]

-3-
Fig. 4
2. Removal of the dust seal
(1) Insert the hooks of the J-204 bearing puller between the commutator and the Dust Seal [31] from
both sides, and fix the hooks with the wing bolts.
(2) Place the J-204 bearing puller on a supporting jig and push down on the armature shaft with a hand
press to remove the Dust Seal [31] together with the Ball Bearing 6000VV [32]. Replace the Dust
Seal [31] with new one because it is damaged by the removal of the Ball Bearing 6000VV [32].
3. Removal of the stator ass'y
(1) After removing the Armature [12], disconnect the internal wires connected to the Brush Holders [34]
and the Switch [40].
(2) Remove the Stator [30] from the Housing [33]. If the Stator [30] cannot be easily removed from the
Housing [33], disassembly can be facilitated by heating the Housing [33] to a temperature of
approximately 60°C (140°F) with an appropriate heating device.
4. Removal of the gear and pinion set
(1) Loosen the four Bolts M5 x 16 [23] and remove the Packing Gland [22] together with the Spindle
[20] and the gear of the Gear and Pinion Set [29] from the Gear Cover Ass'y [4] in a single body.
(2) Remove the Retaining Ring [15] from the Spindle [20].
(3) When it is necessary to remove the gear of the Gear and Pinion Set [29] from the Spindle [20], it is
highly recommended that the special repair tools described below are utilized.
NOTE: Place the assembly on a sleeve that
matches the dimension of the Packing
Gland [22] and push down on the top
of the Spindle [20] with a hand press
to remove the gear of the Gear and
Pinion Set [29] as shown in Fig. 4.
Push.
[15]
[20]
[22]
Sleeve
Gear of the
Gear and Pinion Set [29]

-4-
Fig. 5 Fig. 6
Put the parts together in the reverse order of disassembly, with the precautions given below.
(1) Apply machine oil to Felt Packing (B) [19] then mount it to the Packing Gland [22] to increase the dust
resistance.
(2) Generously lubricate the teeth of the Gear and Pinion Set [29] with grease. Rub grease onto the teeth
with your fingers so that the grease reaches each tooth bottom. Note that under-lubricated Gear and
Pinion Set [29] may wear at a faster rate.
(3) When replacing the Armature [12] and the Ball Bearing 6000VV [32] on the commutator side, press
inward on the Dust Seal [31] while taking care of its direction until the end face of the Dust Seal [31]
hits against the butting surface of the Armature [12] and make sure that the Dust Seal [31] cannot turn
freely as shown in Fig. 6. The Dust Seal [31] is an important element for improved dust protection of
the Ball Bearing 6000VV [32]. Be sure to use a new one at every disassembly work of the Ball Bearing
6000VV [32].
(4) Apply Three Bond TB 1406 screw locking agent to the following screws. (See Fig. 5.)
• Two Machine Screws M5 x 10 [16] which fix Bearing Cover (B) [17] in place
• Four Bolts M5 x 16 [23] which fix the Packing Gland [22] in place
Reassembly
[29]
[16]
[23]
[22]
[17]
Pinion
Gear
[12]
[32]
[31]
[18]
[19]
[20]
[21]

-5-
Fig. 7
Fig. 8
(5) Arrange the internal wires as shown in Fig. 7 and Fig. 8 being careful not to connect in wrong direction
or position and not to get the internal wires caught in parts.
Pass the internal wire covered with the
tube of the stator through this groove.
Pass the internal wire of
the cord through this area.
Fit the internal wire in the groove securely.

-6-
Fig. 9 • Cord clip mounting diagram
(6) Mount the cord clip as shown in Fig. 9 being careful of the direction.
Pinion chamber of the Gear Cover Ass'y [4] --------50 g of COSMO DYNAMAX EP No. 1
Generously rub grease onto the gear, pinion and
inner circumference of the metal.
Tapping Screws D4 x 16 [35] [38] ----------------------------2.0 ± 0.5 N•m (20 ± 5 kgf•cm, 1.5 ± 0.4 ft-lbs.)
Tapping Screw D5 x 35 [1] -------------------------------------3.4 ± 0.7 N•m (35 ± 7 kgf•cm, 2.5 ± 0.5 ft-lbs.)
Bolt M5 x 16 [23] --------------------------------------------------7.8 ± 1.5 N•m (80 ± 15 kgf•cm, 5.8 ± 1.1 ft-lbs.)
Special Nut M10 [6] ----------------------------------------------20.4± 3.1N•m (200± 30 kgf•cm,14.4± 2.2ft-lbs.)
Machine Screw M5 x 10 [16] -----------------------------------5.9 ± 1.5 N•m (60 ± 15 kgf•cm, 4.3 ± 1.1 ft-lbs.)
Lubrication points and type of lubricant
Tightening torque
Cord dia.: Over 8.4 mm Cord dia.: Max. 8.4 mm

-7-
Fig. 10 • Wiring diagram
On completion of disassembly and repair, measure the insulation resistance, and conduct the dielectric
strength test.
Insulation resistance: After the switch is turned on, more than 10 Mby 500 V DC megohm meter
between live parts and accessible metal parts.
Dielectric strength: After the switch is turned on, there must be no trouble when the voltage indicated
below is provided between live parts and accessible metal parts.
Less than 150 V of the rated voltage: 3,000 V x 3 sec.
More than 150 V of the rated voltage: 4,400 V x 3 sec.
After no-load operation for 30 minutes, the no-load current value should be as follows.
Voltage 110 V 120 V 127 V 220 V 230 V 240 V
Current max. 7.2 A 5.7 A 6.0 A 3.7 A 3.9 A 3.2 A
Wiring diagram
Insulation tests
No-load current value
Field coil
Field coil
Switch
Power source Condensor ass'y
(0.22 ȝF)

-8-
MODEL Variable
Fixed 10 20 30 40 50 60 min.
G 18ST
G 18SW2
G 23ST
G 23SW2
General Assembly
Gear Cover
Ass’y
Seal Plate
Handle (A)
Switch
Cord
Ball Bearing
(6301VV)
Rubber Ring
Armature
Dust Seal
Ball Bearing
(6000VV)
Gear and
Pinion Set
Housing
Stator
Bearing
Cover (B)
Ball Bearing
(6302VV)
Felt
Packing (B)
Packing
Gland
Spindle
Work Flow
Wheel Guard
Ass’y
Handle (B)
STANDARD REPAIR TIME (UNIT) SCHEDULES

Model G 18ST
DISC GRINDER
LIST NO. F227
2014·12·11
(E1)
36
1 2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31 32
33
34 35 36
37 38
44
34
35
37
38
39
35
40
41 42
43
45
46
38
501 502 503
602