Makita 6842 Manual

Model No.
Description
PRODUCT
CONCEPT AND MAIN APPLICATIONS
P 1/16
Specification
Standard equipment
6842, 6843, 6844
Auto Feed Screwdriver
Models 6842, 6843 and 6844 have been developed
as the successor models of 6833 series models.
These models feature more reliable casing attachment
with the following benefits:
Rigid aluminum casing
Stopper base with anti-tilt device for preventing screws from swaying
Rubber cap securely fixed to stopper base
Dust-proof construction for smooth sliding action
6842 series also includes Auto feed screwdriver with coil magazine
available as Model 6845.
Dimensions: mm (")
Width (W)
Height (H)
Length (L) 400 (15-3/4) 440 (17-1/4)
6842/ 6843 6844
75 (2-15/16)
243 (9-9/16)
L
H
Optional accessories
W
Specification
Net weight: kg (lbs) 2.0 (4.4) 2.1 (4.6)
Model 6843 6844
Power supply cord: m (ft) Europe: 4.0 (13.1), Other countries: 2.5 (8.2)
6842
6842/ 6843/ 6844
6842/ 6843
Continuous Rating (W)
Voltage (V) Cycle (Hz) Input Output Max. Output (W)
110
120
220
230
240
4.5
4.3
2.3
2.2
2.1
50/60
50/60
50/60
50/60
50/60
470
---
470
470
470
190
190
190
190
190
400
400
400
400
400
Current (A)
Note: The standard equipment for the tool shown above may differ by country.
Phillips bit 2-162 or 2-157 (for 6842/ 6843)
Square bit 2-162 or 2-157 (for 6842/ 6843)
Phillips bit 2-182 or 2-177 (for 6844)
Square bit 2-182 or 2-177 (for 6844)
Extension handle
Casing attachment
Plastic carrying case
Phillips bit 2-162 or 2-157 ....................... 3
Belt clip ................................................... 1
Thumb screw (for fixing Belt clip) .......... 1
Plastic carrying case ................................ 1
6844
Phillips bit 2-182 or 2-177 ....................... 3
Belt clip ................................................... 1
Thumb screw (for fixing Belt clip) .......... 1
Plastic carrying case ................................ 1
4 (5/32)
25 to 55
(1 to 2-3/16)
45 to 75
(1-3/4 to 2-15/16)
Diameter
Overall length
6,000 3,0004,700No load speed: min.-1 = rpm
Driver bit: mm (")
Capacities: mm (")
[collated drywall screw]
Reverse switch
Protection against electric shock
6.35 (1/4) Hex
162 (6-3/8) or 157 (6-3/16) 182 (7-1/8) or 177 (7)
Shank
Overall length*
Yes
Double insulation
*Overall length of driver bit may differ by country.
6842/ 6843
6844
TECHNICAL INFORMATION

P 2/16
[2] LUBRICATION
Apply Makita grease FA.No.2 to the following portions designated with the black triangle to protect
parts and product from unusual abrasion.
[1] NECESSARY REPAIRING TOOLS
CAUTION: Unplug the machine and remove the driver bit from the machine for safety
before repair/ maintenance in accordance with the instruction manual!
Fig. 1
Repair
Description
Bearing setting plate 8.2
Spring pin extractor 2 Removing Pin 2 from Guide box complete
Removing Casing cover and Insulation sleeveRetaining ring S and R pliers
Code No.
1R032
1R266
1R291
Use for
Item No. Description Portion to lubricate
Apply approx. 1g.
Plane bearing 14
Steel ball 3.5 Whole surface
Each depressed portion for Steel ball 4
Steel ball 4 (3 pcs)
Spindle B
Clutch cam C
49
50
52
(a) Drum portion that contacts Plane bearing 14
(b) Cam portion that contacts 52 Clutch cam C
Compression spring 25
Helical gear 57 for 6842
Helical gear 53 for 6843
Helical gear 60 for 6844
(a)
(b)
Armature assembly
Spiral bevel gear 15
Helical gear 13 for 6842
Helical gear 16 for 6843
Helical gear 9 for 6844
Spiral bevel gear 22 Teeth portion that engages Spiral bevel gear 15
Teeth portion that engages Helical gear 57
Teeth portion that engages Helical gear 53
Teeth portion that engages Helical gear 60
Apply approx. 6g.
60
61
49
50
52
61
60
Helical gear (large)
Helical gear (small)
Removing Spiral bevel gear 15Bearing extractor1R269

P 3/16
[3] DISASSEMBLY/ASSEMBLY
[3] -1. Casing Assembly and Feeder Box Assembly
Repair
DISASSEMBLING
Clamper Clamper
Casing complete
Casing complete
4) Clamper and Compression spring 23 can now be
removed from Casing complete.
Fig. 2 Fig. 3
Fig. 4
Disassemble by taking the steps described in Fig. 2 to Fig 17.
2) Then pull off Casing
assembly from Housing.
Casing assembly
3) While pressing Clamper, remove three M4x12 Countersunk
head screws from Casing complete.
1) Loosen M4x28 Thumb screw
by turning counterclockwise.
M4x12 Countersunk head screw (3 pcs):
one on M4x28 Thumb screw side, two on the opposite side
No.1 Phillips
screwdriver
M3x5 (+) Shoulder flat head screw
Fig. 6Fig. 5
Compression spring 23
Clamper
Removing Insulation sleeve from Clamper
While pressing two of the three locking tabs of Insulation
sleeve inward using 1R291, push it off from Clamper.
Clamper
Insulation sleeve
1R291
5) Stopper on either side of Casing complete can be
removed by sliding it in the direction of the gray
arrow while lifting up its rear end with a slotted
screwdriver.
6) Remove M3x5 (+) Shoulder flat head screw
together with Sleeve 4 using No.1 Phillips screwdriver.
rear end
of Stopper
rear end of Stopper
Sleeve 4

P 4/16
[3] DISASSEMBLY/ASSEMBLY
[3] -1. Casing Assembly and Feeder Box Assembly (cont.)
Repair
DISASSEMBLING
Fig. 7
7) While pressing the locking claws of Casing cover inward
using 1R291, pull off Feeder box section from Casing cover.
8) Remove Plate from Stopper base as follows:
while pressing down two Levers at the same time,
push Stopper base towards Feeder box fully until
it stops.
9) While pressing down two Levers
at the same time, separate Feeder box
from Stopper base.
10) Remove Lever and Compression Spring 2 (2 pcs each)
from Feeder box.
Fig. 8
1R291
Feeder box section locking claw
of Casing cover
Casing complete
Feeder box
Plate
Stopper base
Plate
Lever
M4x12 Countersunk
head screw
Dial 42 can now be removed from
Casing complete by unscrewing
M4x12 Countersunk head screw.
Flat washer 6
O Ring 12
Shifter pin
Dial 42
Dial 42
Lever
Compression spring 2
Feeder box
Stopper base
Fig. 9 Fig. 10
Feeder box

P 5/16
[3] DISASSEMBLY/ASSEMBLY
[3] -1. Casing Assembly and Feeder Box Assembly (cont.)
Repair
DISASSEMBLING
Fig. 11
11) Remove Box cover complete from Feeder box
by unscrewing 4x18 Tapping screw.
13) Remove Stopper, Pin 3 and Torsion spring 4
from Feeder box.
Fig. 12 Fig. 13
Ratchet arm complete
Compression spring 6
Spur gear 16
Torsion spring 4
Stopper
Pin 3
Feeder box
Box cover complete
4x18 Tapping screw Feeder box
Side view of Feeder box
after removing Box cover complete
Dust cover Ratchet arm complete
Compression spring 6
Torsion spring 4Stopper
Pin 3
Fig. 14
12) Remove Ratchet arm complete and
Compression spring 6 from Spur gear 16.
14) Remove Dust cover from Feeder box.
Note: Because the bow portion of Dust cover
is easily damaged, be sure to remove carefully
together with Wheel as illustrated to right.
Insert a screwdriver through the hole of
Dust cover into Wheel, then lever up Dust cover
together with Wheel.
Dust cover
Wheel
bow portion of Dust cover
Dust cover Wheel

P 6/16
[3] DISASSEMBLY/ASSEMBLY
[3] -1. Casing Assembly and Feeder Box Assembly (cont.)
Repair
DISASSEMBLING
Fig. 17
17) Remove Sleeve 5 from Feeder box.
If cannot remove by hand, lever it off
using Phillips screwdriver or the like
as illustrated below.
16) Remove Spur gear 16 from Feeder box.
Fig. 15 Fig. 16
15) Remove Shoulder pin 6 from Feeder box.
Spur gear 16
Sleeve 5Phillips screwdriver
Feeder box
Spur gear 16
Sleeve 5
Shoulder pin 6

P 7/16
[3] DISASSEMBLY/ASSEMBLY
[3] -1. Casing Assembly and Feeder Box Assembly (cont.)
Repair
ASSEMBLING
1) Assemble Sleeve 5, Spur gear 16 and Shoulder pin 6 to Feeder box. (See Fig. 17 to Fig. 15 on page 6.)
2) Assemble Wheel together with Dust cover to Feeder box. (See Fig. 14.)
Important 1: Dust cover must be fixed securely to Feeder box as described in Fig. 18.
Important 2: Make sure that Wheel and Spur gear 16 are correctly engaged. (Fig. 19)
3) Assemble Pin 3 and Torsion spring 4 to Stopper (Fig. 20), then assemble them to Feeder box as described in Fig. 21.
Fig. 20
Stopper
Torsion spring 4
Note: Be sure to assemble Torsion spring 4
and Pin 3 to Stopper as illustrated below
before assembling them to Stopper.
Fig. 19
View from Box cover complete side
Top view
Box cover complete side
Feeder box side
Wheel Spur gear 16
Fig. 18
Push the metal plate of Dust cover in the three portions designated by gray star;
especially, be sure to push it securely into the corner designated by "A" until Dust cover stops.
metal plate
of Dust cover
Feeder box
Engaging Wheel with Spur gear 16
1) Engage with .
2) and can be engaged by doing 1).
Pin 3
Hook the bent end on
the groove of Stopper.
Gear portion
Inner sprocket
Outer sprocket
Inner gear
Outer gear
Stopper catching portion
Wheel Spur gear 16
Note: As illustrated to right:
must be engaged with .
must be engaged with .
Fig. 21
Torsion spring 4
Stopper
Pin 3Spur gear 16
The straight end of Torsion
spring 4 must be placed on
the rear wall of the concave
portion.
Wheel
Engage Stopper with so that
the backward movement of Spur gear 16
can be prevented by Stopper.
concave portion
of Feeder box

P 8/16
[3] DISASSEMBLY/ASSEMBLY
[3] -1. Casing Assembly and Feeder Box Assembly (cont.)
Repair
ASSEMBLING
4) Assemble Ratchet arm complete and Compression spring 6 to Spur gear 16. (See Fig. 12 on page 5.)
5) Assemble Box cover complete to Feeder box. (See Fig. 11 on page 5.)
6) Make sure that Wheel moves correctly as described in Fig. 22 by pushing Ratchet arm complete up and down .
7) Make sure that Wheel can be stopped by pushing in Shoulder pin 6. (Fig. 23)
Note:
Do not apply any lubricant oil/grease or anticorrosive oil to the parts illustrated in Fig. 24.
because smooth feeding can be prevented by dirt and dust sticking to such oily/greasy parts.
Fig. 23 Fig. 24
Fig. 22
Wheel
Ratchet arm complete
Wheel moves when Ratchet arm complete is pushed up.
Wheel does not move when Ratchet arm complete is pushed down. (Also refer to Fig. 21 on page 8.)
Wheel
Ratchet arm complete
Shoulder pin 6
Wheel
Wheel
Compression spring 6
Ratchet arm complete
Spur gear 16
Pin 3
Torsion spring 4
Stopper
Shoulder pin 6
Dust cover
Feeder box
Push in.

P 9/16
[3] DISASSEMBLY/ASSEMBLY
[3] -1. Casing Assembly and Feeder Box Assembly (cont.)
Repair
ASSEMBLING
8) Casing complete can be assembled by doing the reverse of the disassembling steps. (Fig. 7 to Fig.2on pages 4 to 3)
Note: Be sure to follow the instructions described in Fig. 25 to Fig. 27.
Fig. 25
Fig. 26
Fig. 27
U-groove
Spring pin 4-12
of Casing complete
Steel ball 3.5
Dial 42
Assembling Dial 42 to Shifter pin
Assembling Plate to Stopper base
Assembling Sleeve 4 to Casing complete
Shifter pin
M4x28 Thumb screw
By placing Shifter pin so that the pin's flat faces towards
the side where M4x28 Thumb screw is mounted,
Spring pin 4-12 of Casing complete fits in the U-groove
of Dial 42 when Dial 42 is assembled to Shifter pin.
Important:
Click stop of Dial 42 does not work without Steel ball 3.5.
Therefore, before assembling Dial 42 to Shifter pin,
make sure that Steel ball 3.5 is mounted in place on
Casing complete.
Plate
Stopper base
Feeder box
Lever Lever
While pressing down two Levers at the same time,
push Stopper base towards Feeder box until it stops,
then hitch Plate to Stopper base.
Sleeve 4 is not reversible when assembled to Casing complete.
Be sure to do as illustrated in "Correct".
While pressing down two Levers at the same time,
pull Stopper base slowly back to the initial position.
Plate is now assembled in place.
M3x5 Shoulder
flat head screw
Casing complete
[cross section
of Sleeve 4]
Sleeve 4
Casing complete
Sleeve 4
Correct
Wrong
M3x5 Shoulder
flat head screw
outside of
Casing complete
The M3x5 Shoulder
flat head screw cannot
be fastened in place.

P 10/16
[3] DISASSEMBLY/ASSEMBLY
[3] -2. Stopper Base Section
Repair
DISASSEMBLING
Disassemble by taking the steps described in Fig. 28 to Fig. 31.
Fig. 28 Fig. 29
Fig. 30 Fig. 31
Guide box complete
Guard
Stopper base
slotted screwdriver
1) Remove Guide box complete from Stopper base together with
Guard first by inserting slotted screwdriver into the rectangular
hole of Stopper base, then by pushing Guide box complete
with the screwdriver.
rectangular hole
Guard
Guide box complete
2) Separate Guard from Guide box complete.
1R266
1R032
3) Guide box complete can be disassembled as illustrated below
using 1R032, 1R266 and arbor press.
(The parts with asterisk: one each on left and right side)
4) Cap can be removed from Stopper base
using slotted screwdriver.
Pin 2*
Guide*
Torsion spring 4*
Guide box
Stopper base
Cap
[3] -3. Clutch Section and Helical Gears
DISASSEMBLING
Disassemble by taking the steps described in Fig. 32 to Fig. 37.
Fig. 32 Fig. 33
1) After removing Casing assembly (Fig. 2
on page 3), remove Belt clip from Housing
by unscrewing M5x13 Screw.
2) Remove Housing (R) from Housing (L) by unscrewing ten
4x20 Tapping screws. Assembly of Screw guide and Guide
attachment can be removed in this step.
Housing
Belt clip
M5x13 Screw
Housing (R)
4x20 Tapping screw
(10 pcs)
Housing (L)
Assembly of Screw guide and Guide attachment

P 11/16
[3] DISASSEMBLY/ASSEMBLY
[3] -3. Clutch Section and Helical Gears (cont.)
Repair
DISASSEMBLING
Disassemble by taking the steps described in Fig. 32 to Fig. 37.
Fig. 34
Fig. 35 Fig. 36
Spindle B
Steel ball 3.5
Sleeve 20
O Ring 18
Dust cover
5) Assembly of Helical gear (large) can be disassembled
by hand as illustrated below.
Plane bearing 14
Flat washer 25 (2 pcs)
Flat washer 26
Compression spring 25
Clutch cam C
Steel ball 4 (3 pcs)
Helical gear (large)
4) The rest of Clutch section can be disassembled
by hand as illustrated below.
Fig. 37
6) Assembly of Helical gear (small) can be disassembled
by hand as illustrated below.
3) Remove Clutch section from Housing (L).
Assembly of Helical gear (small)
can be also removed in this step.
From the removed Clutch section, Ball bearing 608
and Assembly of Helical gear (large) will be separated
by the force of Compression spring 25.
Ball bearing 608
Clutch section
Assembly of Helical gear (large) consisting of:
Helical gear (large), Clutch cam C, Steel ball 4 (3 pcs),
Flat washer 26, Compression spring 25
Housing (L)
Spiral bevel gear 22
Ball bearing 606
Helical gear (small)
Helical gear (large)
Note:
Different gears are used for Helical gear (large) and Helical gear (small)
by model as listed below. Be careful not to confuse them.
Helical gear (small)
Model 6842 Model 6843 Model 6844
Helical gear 57 Helical gear 53 Helical gear 60
Helical gear 13 Helical gear 16 Helical gear 9
Helical gear (large)
Helical gear (small)

P 12/16
[3] DISASSEMBLY/ASSEMBLY
[3] -3. Clutch Section and Helical Gears (cont.)
Repair
ASSEMBLING
Assemble by taking the steps described in Fig. 38 to Fig. 40.
Fig. 38
1) Put Flat washer 26 on the flanged portion of
Clutch cam C.
Note: Make sure that there is no space between
Flat washer 26 and the flanged portion.
2) While turning Compression spring 25
in the direction of the arrow, push it down
until it touches Flat washer 26.
Compression spring 25
Flat washer 26
Clutch cam C
Fig. 39
Fig. 40
Steel ball 4
(3 pcs)
Steel ball 3.5
Clutch cam C Helical gear (large)
Sleeve 20
O Ring 18
Dust cover
Plane bearing 14
3) Apply Makita grease FA.No.2 to
the inside wall of Clutch cam C
to prevent Steel balls from falling
off from Clutch cam C.
5) Assemble the parts illustrated below into Clutch section.
4) Put each Steel ball 4 in the concave portion on the inside wall
of Clutch cam C.
Then assemble Clutch cam C to Helical gear (large).
Ball bearing 608
Assembly of Helical gear (large)
Spindle B
Flat washer 25 (2 pcs)
Note: Apply Makita grease FA.No.2 to the cam portion of
Spindle B to prevent Flat washer 25 (2 pcs) from falling off
from Spindle B.

P 13/16
[3] DISASSEMBLY/ASSEMBLY
[3] -4. Motor Section
Repair
ASSEMBLING
1) Remove Casing assembly (Fig.2on page 3).
2) Disassemble Housing (R) from Housing (L). (Figs. 32, 33 on page 10)
3) Disassemble Motor section by taking the steps described in Fig. 41 to Fig. 43.
Fig. 41 Fig. 42
Do the reverse of the disassembling steps.
Note: Do not forget to mount O ring 24 on Ball bearing 6000LLB. (leftt in Fig. 43)
Retaining ring S-6
1R291
Spiral bevel gear 15
O ring 24
1R269
[3] -5. Switch
Put the projection on Switch between the prongs of F/R change lever,
then assemble the Switch to Housing (L). (Fig. 44)
Fig. 44
F/R Change Lever
Switch projection
prong
DISASSEMBLING
Brush holder cap
Carbon brush
Fig. 43
3) Remove O ring 24, Retaining ring S-6 and Spiral bevel gear 15 as illustrated below.
2) Remove Armature by tapping Endbell complete
with plastic hammer.
Endbell complete
Field
Armature
Power supply cord
Ball bearing 6000LLB
1) Remove Motor section (Armature, Endbell complete, Field) from
Housing (L) together with Power supply cord, then remove Carbon brush.
ASSEMBLING

P 14/16
Circuit diagram
Fig. D-1
Color index of lead wires' sheath
Black
White
Red
Orange
Purple
Clear
Switch trigger
Power supply cord
Noise
suppressor
Note on Noise suppressor
1) Noise suppressor and Earth terminal (Ground
terminal) are not used for some countries.
2) Some countries use two-wire Noise suppressor.
For some countries,
blue wire is used
instead of white.
For some countries,
brown wire is used
instead of black.
Switch
Housing (L) side Housing (R) side
Lock button AB
Field
Brush
holder
Brush
holder
Endbell
complete
Housing (L) side Housing (R) side
The color of Lead wire to Brush holder
Orange wire is connected to
Brush holder on Housing (L) side.
Purple wire is connected to
Brush holder on Housing (R) side.
A
B
Earth terminal
(Ground terminal)

P 15/16
Wiring diagram
Fig. D-3
Fig. D-2
Fig. D-4
[1] Wiring on Endbell Complete
Route Lead wires on Endbell complete as described in
Figs. D-2, D-3 (viewed from Housing (L) side) and
Fig. D-4 (viewed from Field side).
Endbell complete,
viewed from Housing (L) side
protrusion (for Strain relief)
Lead wire holder
Housing (R) side
Lead wire to Brush holder (orange)
Lead wire to Brush holder (purple)
Brush holder
Housing (L) side
Housing (L)
Endbell complete
protrusion (for Strain relief)
of Endbell complete
Housing (R)
Endbell complete,
viewed from Field side
(See Fig. D-4.)
protrusion
(for Strain relief)
(See Figs. D-2, D-3.)
Fix the following Lead wires with
Lead wire holders and the groove:
*Field lead wire (white)
*Field lead wire (black)
*Lead wire to Brush holder (orange)
groove
When assembling Field to Endbell complete,
be sure to place the red Lead wire side of Field
on the protrusion side of Endbell complete.
Route each Lead wire to Brush holder as illustrated below.
Field
Pass Lead wire to Brush holder (purple)
through this opening of Endbell complete.
Brush holder
Ring terminal
Connector
Lead wire to Brush holder
Field side
Connect each Lead wire (orange, purple)
to Brush holder as illustrated below.
Inside of Endbell complete,
viewed from Housing (L) side
Field

P 16/16
Wiring diagram
Fig. D-5
[2] Wiring in Housing
Field
Switch
Endbell complete
Strain relief
Noise
suppressor
Earth terminal
(Ground terminal)
for Noise suppressor
screw boss
Note: Noise suppressor and Earth terminal (Ground terminal) are not used for some countries.
The following Lead wires must be tight between
Switch terminal and Lead wire holder:
*Lead wire to Brush holder (orange)
*Field lead wire (red)
Route the following Lead wires between
this screw boss and the inside wall of Housing (L):
*Lead wire to Brush holder (purple)
*Field lead wire (white)
Fix the following Lead wires
with this Lead wire holder:
*Lead wire to Brush holder
(purple)
*Lead wire to Brush holder
(orange)
*Field lead wire (white)
*Field lead wire (red)
rib A
rib B
Route all Lead wires
between rib A and rib B.
Put Noise suppressor in place
so that the wire side faces
towards Strain relief.