Confidential G Series Disc Grinder User Manual

Confidential G Series Disc Grinder

WARNING: Before attempting disassembly, be sure to turn off the power switch and disconnect the power cord plug from the outlet.

Precautions on disassembly and reassembly

[Bold] numbers in the description below correspond to the item numbers in the parts list and exploded assembly diagram for the Models G 12SA4 and G 12SA4(S), and numbers to those for the Models G 13SB4 and G 13SB4(S).

Disassembly

1. Removal of the armature and stator
2. Loosen the Tapping Screw (W/Flange) D4 x 20 [51]<51> and pull out the Tail Cover [50]<50>. Remove the Carbon Brushes (1 Pair) [38]<38> from the Brush Holders [36]<36>.
3. Loosen the four Seal Lock Screws (W/Sp. Washer) M4 x 14 [7]<7> and remove the Packing Gland [6]<6> ass’y and Lever Holder [8]<8>.
4. Loosen the four Tapping Screws (W/Flange) D4 x 25 [1]<1> that fix the Gear Cover [2]<2> to remove the Armature [24]<24> from the Housing [34]<34> together with the Diffuser [23]<23>. At this time, check that the Rubber Bushing [33]<33> is fitted in the housing ball bearing chamber.
5. Carefully wrap the Armature [24]<24> with a soft, clean rag to protect it from being damaged, and clamp it securely in a vise. Then remove the Special Nut M7 [18]<18> and extract the Gear and Pinion Set [25]<25>.
6. Disconnect the four internal wires of the Stator [30]<30> from the Pushing Button Switch [40]<40> and Brush Holders [36]<36>.
7. Remove the Fan Guide [29]<29> and Stator [30]<30> from the Housing [34]<34>.
   NOTE: If the Stator [30]<30> is hard to be removed from the Housing [34]<34>, heat the Housing [34]<34> up to about 60°C to facilitate removal. Then pull out the Rubber Bushing [33]<33>.

  * Each internal wire of the Stator [30]<30> is covered with a glass tube. Do not bend the internal wires repeatedly and do not peel off the glass tubes when removing the Stator [30]<30> from the Housing [34]<34>. Otherwise, the internal wires may be disconnected.
  * Do not apply excessive force to the terminals of the Stator [30]<30> when removing them from the Pushing Button Switch [40]<40> and Brush Holders [36]<36>. Otherwise, the terminals of the Stator [30]<30> may be broken.

2. Removal of the rubber bushing
   Insert the special repair tool J-201 spring hook (Code No. 970977) between the Rubber Bushing [33]<33> assembled in the Housing [34]<34> and the housing ball bearing chamber, and then pull out the Rubber Bushing [33]<33>.

3. Removal of the dust seal

4. Insert the hooks of the J-204 bearing puller between the Ball Bearing 698SS [32]<32> and the Dust Seal [31]<31> and fix the hooks with the wing bolts.
   NOTE: Be careful not to insert the hooks excessively.

5. Put the bearing puller on an appropriate stand. Press down on the armature shaft with a hand press and pull out the Ball Bearing 698SS [32]<32>.

6. Pull out the Dust Seal [31]<31> from the armature shaft.

7. Removal of the gear and spindle

8. Loosen the four Seal Lock Screws (W/Sp. Washer) M4 x 14 [7]<7> and remove the Packing Gland [6]<6> from the Gear Cover [2]<2>.

9. Remove the Retaining Ring for D12 Shaft [4]<4> that secures the gear to the Spindle [12]<12>.

10. When it is necessary to remove the gear from the Spindle [12]<12>, it is highly recommended that the special repair tool J-245-3 sleeve (Code No. 307720) described below is utilized. Place the assembly on a sleeve that matches the dimension of the Packing Gland [6]<6> and press down on the top of the Spindle [12]<12> with a hand press to remove the gear as shown in Fig. 1.
    

11. Removal of the pushing button switch

12. Disconnect the two internal wires of the Stator [30]<30> and two internal wires of the Noise Suppressor [43]<43> from the Pushing Button Switch [40]<40>.

13. Remove the Cord [52]<52> from the side rib of the Housing [34]<34>.

14. Push the Slide Bar [49]<49> and Slide Knob [47]<47>. Leave a 6- mm gap between the Slide Bar [49]<49> and Housing [34]<34>.
    Pull the Pushing Button Switch [40]<40> as shown in Fig. 2.

15. Remove the Cord [52]<52> from the Pushing Button Switch [40]<40>.

Reassembly

Reverse the disassembly procedure to reassemble. Note the following points.

1. Rub grease into the teeth of the Gear and Pinion Set [25]<25> with your fingers so that the grease reaches each tooth bottom. Note that under-lubricated Gear and Pinion Set [25]<25> may wear at a faster rate.

2. When replacing the Armature [24]<24> and the Ball Bearing 698SS [32]<32> on the commutator side, press the Dust Seal [31]<31> in while carefully noting its direction until the end face of the Dust Seal [31]<31> contacts the butting surface of the Armature [24]<24>, and check that the Dust Seal [31]<31> cannot turn freely. (See Fig. 3.) The Dust Seal [31]<31> is an important element for improved dust protection of the Ball Bearing 698SS [32]<32>. Be sure to replace the Dust Seal [31]<31> with new one at every disassembly work. Fit the Rubber Bushing [33]<33> into the housing ball bearing chamber before installing the Armature [24]<24>. (See Fig. 4.)

3. When installing the Stator [30]<30> into the Housing [34]<34>, insert it while being careful about correctly placing the internal wires of the Stator [30]<30> as shown in Fig. 5. Connect the four internal wires of the Stator [30]<30> correctly as shown in Fig. 6.
   NOTE:

   • Be careful not to put the internal wire of the Carbon Brush (1 Pair) [38]<38> on the top of the Brush Holders [36]<36> when connecting the internal wires of the Stator [30]<30> or when connecting the Carbon Brush (1 Pair) [38]<38>.
   • Each internal wire of the Stator [30]<30> is covered with a glass tube. Do not bend the internal wires repeatedly and do not peel off the glass tubes when mounting the Stator [30]<30> to the Housing [34]<34>. Otherwise, the internal wires may be disconnected.
   • Do not apply excessive force to the terminals of the Stator [30]<30> when inserting them into the Pushing Button Switch [40]<40> and Brush Holders [36]<36>. Otherwise, the terminals of the Stator [30]<30> may be broken.

4. Be sure to soak the inner diameter of the Felt Packing [9]<9> with machine oil. Otherwise, its dust sealing function will fail to work properly, resulting in premature damage to the ball bearing of the Packing Gland [6]<6>. Wipe the Felt Packing [9]<9> lightly with a rag before assembling.

5. Mount the Fan Guide [29]<29> in proper direction by matching the gate mark of the Fan Guide [29]<29> with the “N” mark of the Housing [34]<34> as show in Fig. 7.

6.  Do not catch the pigtail of the Carbon Brush (1 Pair) [38]<38> in the Tail Cover [50]<50> when mounting the Tail Cover [50]<50>. Check that the pigtail is in its proper position as shown in Fig. 8 before mounting the Tail Cover [50]<50>.
   

7. Tighten three of the four Seal Lock Screws (W/Sp. Washer) M4 x 14 [7]<7> except the one for securing the Lever Holder [8]<8>. Mount the Lever [27]<27> and Retaining Ring D4 [28]<28> to the Lever Holder [8]<8>. Hook the Spring [26]<26> on the Lever [27]<27>. Then tighten the remaining Seal Lock Screw (W/Sp. Washer) M4 x 14 [7]<7>.

8. Mount the Pushing Button Switch [40]<40> according to the following steps.

   • Attach the Cord [52]<52> to the Pushing Button Switch [40]<40>.
   • Mount the Pushing Button Switch [40]<40> while pressing the pressing point of the Pushing Button Switch [40]<40> as shown in Fig. 9.
   • Mount the Ferrite Core [42]<42> and Cord [52]<52> as shown in Fig. 10.
     

Lubrication point and type of lubricant

NOTE: Use a brush when rubbing grease.

1. When replacing the Gear Cover [2]<2>, lubricate the inner circumference of the needle bearing with 0.3 g of Cosmo Molybdenum No. 1 grease.
2. Rub 18 g of Cosmo Molybdenum No. 1 grease into the pinion chamber of the Gear Cover [2]<2>.
3. Rub 2 g of Cosmo Molybdenum No. 1 grease into the teeth of the gear.
4. Rub 0.7 g of Cosmo Molybdenum No. 1 grease into the teeth of the pinion.

Tightening torque

± 4
[39] <39>| Tapping Screw D3 x 8| 0.74 – 0

0.25

| 0.54 – 0

0.18

| 7.5 – 0

2.5

[46] <46>| Tapping Screw (W/Flange) D4 x 12| 2.0 ± 0.5| 1.5 ± 0.4| 20 ± 5
[51] <51>| Tapping Screw (W/Flange) D4 x 20 (Black)| 2.0 ± 0.5| 1.5 ± 0.4| 20 ± 5

Insulation test

Measure the insulation resistance and dielectric strength after reassembly.

• Insulation resistance: 7 MΩ or higher (as measured with a 500 VDC megaohm tester)
• Dielectric strength: 4,000 VAC/minute, with no abnormalities ————– 230 V to 240 V
  2,500 VAC/minute, with no abnormalities ————– 120 V

No-load current value
After no-load operation for 30 minutes, the no-load current values should be as follows.

Wiring diagram

STANDARD REPAIR TIME (UNIT) SCHEDULES

Button

Switch Tail Cover Cord

Cord Armor Ferrite Core

| | Armature Dust Seal Ball Bearing

698SS

Special Nut

M7

Pinion (Gear and

Pinion Set)

| Packing

Gland Spindle

Felt Packing Fringer Gear

(Gear and Pinion Set)

Retaining Ring for D12 Shaft

O-ring

Lever Holder Lever

Spring Retaining

Ring D4

|
G 12SA4| | Work Flow|
Housing Stator Slide Bar Slide Switch Knob Rubber

Bushing

|
G 13SB4| |
|

General Assembly

|
| | Brush Holder

Noise

Suppressor Cord Clip

| | Gear Cover Seal Ring (A) Washer (C) Ball Bearing

629VV

Retaining Ring for D26 Hole

Lock Pin Pushing

Button Diffuser

ITEM NO.| CODE NO.| DESCRIPTION| NO. USED| REMARKS
---|---|---|---|---
1| 307028| TAPPING SCREW (W/FLANGE) D4 X 25 (BLACK)| 4|
2| 375889| GEAR COVER| 1|
3| 301943| LOCK PIN| 1|
4| 939542| RETAINING RING FOR D12 SHAFT (10 PCS.)| 1|
5| 375899| O-RING| 1|
6| 375887| PACKING GLAND| 1|
7| 376226| SEAL LOCK SCREW (W/SP. WASHER) M4 X 14| 4|
8| 375894| LEVER HOLDER| 1|
9| 376227| FELT PACKING| 1|
10| 376228| FRINGER| 1|
11| 375900| O-RING| 1|
12| 375895| SPINDLE| 1|
13| 375904| WHEEL GUARD| 1|
14| 376067| WHEEL WASHER| 1|
15| 316822| D. C. WHEELS 125MM A36Q (25 PCS.)| 1|
16| 339579| WHEEL NUT M14| 1|
17| 336535| PUSHING BUTTON| 1|
18| 301941| SPECIAL NUT M7| 1|
19| 308543| SEAL RING (A)| 1|
20| 980866| WASHER (C)| 1|
21| 629VVM| BALL BEARING 629VV| 1|
22| 939554| RETAINING RING FOR D26 HOLE (10 PCS.)| 1|
23| 336542| DIFFUSER| 1|
24| 361131E| ARMATURE 230V| 1|
24| 361131F| ARMATURE 240V| 1|
25| 375888| GEAR AND PINION SET| 1|
26| 376229| SPRING| 1|
27| 375892| LEVER| 1|
28| 6685336| RETAINING RING D4| 1|
29| 336530| FAN GUIDE| 1|
30| 341070F| STATOR 230 V-240 V| 1|
31| 336536| DUST SEAL| 1|
32| 336871| BALL BEARING 698SS| 1|
33| 309929| RUBBER BUSHING| 1|
34| 375878| HOUSING| 1|
35| | NAME PLATE| 1|
36| 336537| BRUSH HOLDER| 2|
37| 336872| CUSHION SPONGE| 2|
38| 999088| CARBON BRUSH (1 PAIR)| 2|
39| 328210| TAPPING SCREW D3 X 8| 4|
40| 376232| PUSHING BUTTON SWITCH| 1|
40| 376230| PUSHING BUTTON SWITCH| 1| FOR GBR, EUROPE(S)
41| 980063| TERMINAL| 2|
42| 334379| FERRITE CORE| 1|
43| 375898| NOISE SUPPRESSOR| 1|
44| 953327| CORD ARMOR D8.8| 1|
45| 937631| CORD CLIP| 1|
46| 305720| TAPPING SCREW (W/FLANGE) D4 X 12| 1|
47| 314428| SLIDE KNOB| 1|
48| | BRAND LABEL| 1|
49| 375882| SLIDE BAR| 1|
50| 370047| TAIL COVER| 1|
51| 301653| TAPPING SCREW (W/FLANGE) D4 X 20 (BLACK)| 1|
52| 500247Z| CORD| 1|
52| 500435Z| CORD| 1| FOR GBR, UAE
52| 500234Z| CORD| 1| FOR RUS, IND
52| 500439Z| CORD| 1| FOR AUS, NZL
STANDARD ACCESSORIES
501| 938332Z| WRENCH| 1|
502| 994322| SIDE HANDLE| 1|
502| 336865| SIDE HANDLE| 1| FOR VIBRATION-ABSORBING
503| 376233| CASE| 1|

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