Makita Maktec MT912 Manual

Model No.

Description

MT912

Die Grinder L

Dimensions: mm (")

Width (W)

Height (H)

Length (L) 350 (13-3/4)

75 (2-15/16)

Wrench ..................................... 2

Collet cone 6mm or 1/4” .......... 1

Insulation cover ........................ 1 (for some countries only)

PRODUCT

CONCEPT AND MAIN APPLICATIONS

P 1/ 1

Specification

Standard equipment

Optional accessories

Note: The standard equipment for the tool shown above may vary by country.

Collet cones (3mm, 6mm, 1/8”, 1/4”)

Continuous Rating (W)

Voltage (V) Cycle (Hz) Input Output

140

Max. Output (W)

110

220

240

4.6

2.1

50/60

480

380

140 380120 4.2 50/60 ---

380

Current (A)

140

2.3

230 50/60 480 3801402.2

Model MT912 has been developed as the cosmetic change model of

maktec die grinder MT911.

Its main features are:

•Industrial performance and durability at less expense

•Anti-slip ribs on motor housing for higher maneuverability and

better control

Collet size*1

*1: 3mm and 1/8” shank collets can be used by changing Collet cone.

*2: Max wheel diameter for China is the same of 20mm (13/16”).

*3: with Collet nut, Collet cone

6mm or 1/4”

Max wheel diameter*2: mm (")

33,000

20 (13/16)

2.0 (6.6)

1.4 (3.1)

Weight according to

EPTA-Procedure 01/2003*3: kg (lbs)

Double insulationProtection against electric shock

No load speed: min.ˉ¹=rpm

Power supply cord: m (ft)

TECHNICAL INFORMATION

P /1

Repair

[1] NECESSARY REPAIRING TOOLS

CAUTION: Repair the machine in accordance with “Instruction manual” or “Safety instructions”.

Code No. Description Use for

1R031 Bearing setting pipe 28-20.2 mounting Ball bearing 6001ZZ to Barrel

1R045 Gear extractor (large) removing/mounting Ball bearing 6001ZZ from/to Spindle

1R291 Retaining ring S & R pliers removing/mounting Retaining ring S-12 from/to Spindle

1R232 Pipe 30 supporting Barrel when removing Spindle

1R247 Round bar for Arbor 20-100 removing Ball bearing 629ZZ from Barrel

1R250 Round bar for Arbor 26-100 mounting Ball bearing 629ZZ to Barrel

1R269 Bearing extractor removing Ball bearing 607ZZ from Armature

1R282 Round bar for Arbor 8-50 •attaching to 1R045 when mounting Ball bearing 6001ZZ to Spindle

•attaching to arbor press when removing Armature from Gear housing cover

784416-4 Socket bit 17-55 removing/mounting Coupling

[2] LUBRICATION

Apply Lubricant VG100 to the following portions designated with the black triangle to protect parts and product from

unusual abrasion.

Fig. 1

Item No.

4 Felt ring 17

O ring 26

Bearing retainer

Spindle

Barrel

Coupling

Ball bearing 629ZZ

Flat washer 22

Whole portion

enough to be absorbed

in Felt ring 17 entirely

a little

Description AmountPortion to lubricate

P /1

Repair

[3] DISASSEMBLY/ASSEMBLY

[3] -1. Barrel Section

DISASSEMBLING

(1) Remove Insulation cover from Barrel if the cover is used.

(2) Disassemble Coupling and Bearing retainer from Barrel as drawn in Fig. 2.

2. While holding Spindle with Wrench

13, remove Collet nut 6 with another

Wrench 13 by turning it counter-

clockwise.

1. Unscrew four 4x25 Tapping screws,

then separate Barrel section from

Motor housing.

Note: Flat washer 22 between

Gear housing cover and

Barrel may be removed

at this time. Do not lose it.

3. Remove Collet cone 6.0

from Spindle.

4. Remove Spacer from Coupling. And then

remove Flat washer 22 from Barrel if the

washer is still in Barrel.

5. While holding Spindle with Wrench 13, remove Coupling

from Barrel with Impact driver and 784416-4 by turning it

counterclockwise.

6. Fix Barrel in Vise. Then remove Bearing

retainer with Adjustable wrench by

turning it counterclockwise

7. Remove Felt ring 17 and Flat washer 18 from Barrel.

Wrench 13

Spindle

Collet nut 6

Collet cone

784416-4

Coupling

Barrel

Bearing

retainer

Wrench 13

Fig. 2

Flat washer 18

Felt ring 17

Vise

Note: Felt ring 17 may be removed

with Bearing retainer in the

previous step.

Barrel

Gear housing

cover

Spacer

Coupling

Flat washer 22

Adjustable

wrench

Repair

DISASSEMBLING

(3) Spindle section is now removed from Barrel as drawn in Fig. 3.

3. Remove Retaining ring S-12 with 1R291 from Spindle. 4. Remove Ball bearing 6001ZZ with 1R045

from Spindle.

1. Put Barrel on 1R232. And then remove Spindle by pressing

1R282 with Arbor press.

2. Remove Ball bearing 629ZZ from Barrel

by pressing 1R247 with arbor press.

Fig. 3

1R232

Ball bearing

6001Z

Ball bearing 629Z

Spindle

1R282

Ball bearing

6001Z

Spindle

Retaining

ring S-12

Ball bearing

629Z

Barrel

1R247

[3] DISASSEMBLY/ASSEMBLY

[3] -1. Barrel Section (cont.)

1R291

1R045

P 4/11

1R250

P 5/11

Repair

ASSEMBLING

(1) Assemble Spindle section as drawn in Fig. 4.

(2) Assemble Ball bearing 629ZZ to Barrel, and then assemble the Spindle section to Barrel. (Fig. 5)

(3) Assemble Flat washer 18, Felt ring 17 and Bearing retainer to Barrel as drawn in Fig. 6.

Fig. 4

Fig. 5

Ball bearing

6001ZZ

Ball bearing

6001Z

1R045

Spindle

1. Insert 1R282 into the hole of Spindle. Then mount

Ball bearing 6001ZZ to Spindle with 1R045.

1. Assemble Ball bearing 629ZZ to Barrel

by press-fitting 1R250.

2. While supporting Ball bearing 629ZZ of Barrel with 1R250,

assemble Spindle section to Barrel by press-fitting with 1R031.

1R282 1R282

Retaining

ring S-12

2. Install Retaining ring S-12 to Spindle with 1R291

in order to secure Ball bearing 6001ZZ.

Ball bearing 629Z

1R250

Ball bearing

629ZZ

1R031

[3] DISASSEMBLY/ASSEMBLY

[3] -1. Barrel Section (cont.)

Fig. 6

Flat washer 18

3. Fix barrel with Vise, and then fasten Bearing retainer to

Barrel by turning it clockwise with Adjustable wrench.

Felt ring 17

Bearing retainer

2. Stuff Felt ring 17

into Bearing

retainer.

5. Mount Flat washer 22 to Barrel.

1. Mount Flat washer 18 to Barrel

by passing through Spindle.

Bearing

retainer

Spindle

Flat washer 22

784416-4

Wrench 13

4. While holding Spindle with Wrench 13, mount Coupling

with Impact driver and 784416-4 by turning it clockwise.

Coupling

P 6/11

Repair

ASSEMBLING

(4) Assemble Barrel to Motor housing. (Fig. 7)

Note in Assembling: When Barrel section is assembled to Motor housing, Rotation direction mark of Barrel

must be positioned on the same side of Switch knob.

(5) Mount Insulation cover to Barrel if the cover is used. (Fig. 8)

Spindle

Rotation direction mark

Motor housing

Switch knob

Barrel

Name plate

Fig. 7

[3] DISASSEMBLY/ASSEMBLY

[3] -1. Barrel Section (cont.)

Insulation coverConcave portion

Concave portion

Protrusion

While fitting the protrusion of Insulation cover to the concave portion on Barrel,

mount Insulation cover to Barrel.

Switch knob

Barrel

Fig. 8

[3] -2. Armature

DISASSEMBLING

1. Remove Brush holder caps

and Carbon brushes.

Brush holder caps

Carbon brushes

2. Separate Barrel section from

Motor housing.

3. Remove Armature together with Gear

housing cover from Motor housing.

4. Remove Spacer from

Coupling on Armature.

5. While holding Armature by hand, remove

Coupling with Impact driver and 784416-4

by turning it counterclockwise.

6. Disassemble Armature from Gear

housing cover by pressing Armature

shaft with 1R282 and Arbor press.

Spacer

Coupling

784416-4

1R282

Coupling

(1) Disassemble Armature as drawn in Fig. 9.

Fig. 9

Gear housing cover

Motor housing

Armature

P 7/ 11

Repair

[3] DISASSEMBLY/ASSEMBLY

[3] -2. Armature (cont.)

[3] -3. Field

DISASSEMBLING

1. Remove Labyrinth

rubber ring 19 by hand.

2. Remove Ball bearing 629ZZ with 1R269.

And then, remove Insulation washer.

Fig. 10

(1) Remove Brush holder caps and Carbon brushes. (Refer to Fig. 9)

(2) Disassemble Barrel section and Armature together with Gear housing cover. (Refer to Fig. 9)

(3) Disassemble Field from Motor housing as drawn in Fig. 11.

Fig. 11

Labyrinth

rubber ring 19

Ball bearing

629ZZ

1. Remove Baffle plate,

then unscrew two

4x70 Tapping screws.

2. Install two M4x25 Tapping screws in the holes on two diagonal corners of

Motor housing. Then, remove Field from Motor housing by alternately

tapping the screw heads.

Note: Do not tap the diagonal corners directly because the inlaid portion

near the corners is fragile.

Insulation

washer

1R269

M4x25 Tapping screws

4x70 Tapping

screws

Baffle plate

Field

(2) Disassemble Armature section. (Fig. 10)

Assemble Armature section by reversing the disassembly procedure. (Refer to Figs. 10 and 9)

Assemble Field by reversing the disassembly procedure. (Refer to Figs. 11 and 9)

ASSEMBLING

Circuit diagram

P 8/ 11

Color index of lead wires' sheath

Connect Brush holder's lead wire (black) from

Field lead wire (black) to Brush holder of

maktec logo side.

Switch

Terminal

block

Motor housing

Rear cover

maktec

logo side

Field Field

Noise suppressor is not used

for some countries.

Noise suppressor's lead wire is white in

case of that of two lead wire type is used.

(without grounding lead wire).

Correct Wrong

Spindle rotates in the inverse direction

to the indication on Barrel.

Fig. R Fig. F

Fig. D-1

maktec logo

Field Lead Wire (black) Field Lead Wire (white)

Brush Holder's

Lead Wire (black) Brush Holder's

Lead Wire (black)

Grounding terminal of

Noise suppressor

Black

White

Blue

Brown

Lead wire (white) is used

for some countries instead

of the lead wire (blue).

Lead wire (black) is used

for some countries instead

of the lead wire (brown).

Clear

Noise

suppressor

Motor housing Motor housing

Wiring diagram

P 9/ 11

Motor housing

Support

Field lead wire

(white) for connecting

to Switch

Field lead wire

(black) for connecting

to Terminal block

Support

Motor housing of Rear cover side

Noise suppressor

Grounding terminal of

Noise suppressor

Pass Field lead wires (black and white) through the holes of Motor housing.

Insert the grounding terminal of noise suppressor's lead wire deeply into the hole of Motor housing.

Install Noise suppressor to the space painted with gray color in Fig. D-2.

Pass Field lead wires (black and white) through the groove of Support while tightening them between

Motor housing and Support.

Groove of Support

Groove of

Support

Field lead wire (white)

Field lead wire

(black)

to Switch

to Terminal block

Tighten Field lead wires between

Motor housing and Support.

Fig. D-2

Fig. D-3

Wiring diagram

P 10/ 11

Support section

Fig. D-5

Left side view

Lead wire (blue or white)

of Power supply cord

Connecting terminal

Connect Connecting terminal to

Switch as follows.

* Screw hole side: Top

* Lead wire side: Bottom

Terminal block

Switch

Fig. D-4

Install Terminal block and Switch to Support. (Fig. D-4)

Switch

Terminal block

Support

Switch

Terminal block

Noise suppressor

Left

Top

Bottom

Lead wire (brown or black)

of Power supply cord

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