JUKI MO-6700D, MO-6704D, MO-6714D, MO-6716D Series Manual
40033638
No.E368-00
ENGINEER’S MANUAL
HIGH SPEED SEMI-DRY HEAD OVERLOCK/INTERLOCK/
SEWING MACHINE
MO-6700D Series
®
PREFACE
This Engineer’s Manual is written for the technical personnel who are responsible for the service and maintenance
of the machine.
The Instruction Manual for these machines intended for the maintenance personnel and operators at an apparel
factory contains operating instructions in detail. And this manual describes “Standard Adjustment”, “Adjustment
Procedures”, “Results of Improper Adjustment”, and other important information which are not covered by the
Instruction Manual.
It is advisable to use the relevant Instruction Manual and Parts List together with this Engineer’s Manual when
carrying out the maintenance of these machines.
In addition, for the motor for the sewing machine with thread trimmer, refer to the separate Instruction Manual or
Engineer’s Manual for the motor. And for the control panel, refer to the Instruction Manual for the control panel.
This manual gives the “Standard Adjustment” on the former page under which the most basic adjustment value is
described, and on the latter page “Results of Improper Adjustment” under which stitching errors and troubles
arising from mechanical failures are described together with the “Adjustment Procedures”.
CONTENTS
1. SPECIFICATIONS.......................................................................................... 1
(1) MO-6700D SERIES ......................................................................................................1
2. MODEL NUMBERING SYSTEM.................................................................... 2
3. ST ANDARD ADJUSTMENT .......................................................................... 4
(1) Adjusting the needle height.......................................................................................4
(2) Positioning the throat plate .......................................................................................4
(3) Installing position of the needle clamp ....................................................................6
(4) Adjusting the length of the lower looper holder
(Applicable only to MO-6716D series) ......................................................................6
(5) Adjusting the lower looper ........................................................................................8
1) Returning amount of the lower looper ..................................................................................................8
2) Clearance between the lower looper and the needle...........................................................................8
(6) Position of the upper looper guide .........................................................................10
(7) Positioning the upper looper holder.......................................................................12
(8) Positioning the upper looper...................................................................................14
1) Height of the upper looper..................................................................................................................14
2) Longitudinal position of the upper looper ...........................................................................................14
(9) Adjusting the double chain looper (Applicable only to MO-6716D series) .........16
1) Returning amount of the double chain looper ....................................................................................16
2) Longitudinal motion (Avoid motion)....................................................................................................16
3) Clearance between the double chain looper and the needle .............................................................16
(10) Adjusting the height and clearance of the needle guard......................................18
1) For 1-needle or 2-needle overlock machine.......................................................................................18
2) For safely stitch machine ...................................................................................................................18
(11) Adjusting the height of the feed dog ......................................................................20
(12) Adjusting the tilt of the feed dog.............................................................................20
(13) Adjusting the differential feed ratio ........................................................................22
(14) Longitudinal position of the feed dog ....................................................................22
(15) Adjusting the presser foot.......................................................................................24
1) Adjusting the tilt of the presser foo....................................................................................................24
2) Adjusting the micro-lifting mechanism of the presser foot.................................................................24
(16) Positioning the upper knife arm shaft ....................................................................26
(17) Positioning the upper and lower knives, and available overedge widths...........26
1) Lower knife.........................................................................................................................................26
2) Upper knife.........................................................................................................................................26
3) Overdging width .................................................................................................................................26
(18) Resharpening of the knife........................................................................................28
(19) Position of the thread cam (Applicable only to MO-6716D series) ......................28
1) Adjustment of the thread cam ............................................................................................................28
2) Adjusting looper thread cam thread guides A and B and the looper thread cam nail.........................28
3) Adjusting looper thread auxiliary thread take-up lever (Exclusive for 30P)........................................30
(20) Adjusting the throat plate support..........................................................................32
(21) Adjusting the feed mechanism cover presser.......................................................32
(22) Adjusting the looper cover ......................................................................................34
(23) Adjusting the cloth chip cover ................................................................................34
(24) Position of the thread guides and the looper thread take-ups.............................36
(25) Adjusting soft chain making mechanism...............................................................38
1) Replacing the parts with those exclusively designed for making soft chains .....................................38
2) Adjustment value................................................................................................................................38
3) Important points in adjustment ...........................................................................................................39
4. ADDITIONAL INFORMATION AND PRECAUTIONS.................................. 40
(1) Thread tension............................................................................................................40
1) Strength of tension spring ..................................................................................................................40
2) Springs used for each model .............................................................................................................40
(2) Upper looper .............................................................................................................40
(3) Center-to-center distance of the upper looper holder ..........................................41
(4) Caution in assembly.................................................................................................41
1) Application of sealant .........................................................................................................................41
2) Precautions to be taken with respect to the lubricating components .................................................43
3) Applying the exclusive grease............................................................................................................44
(5) Kinds of motor pulleys, belts and frame support plate bolts...............................46
1) Motor pulleys and belts ......................................................................................................................46
2) Pat No. of frame support plate bolt ....................................................................................................46
5. ADJUSTMENT VALUES OF THE NEEDLE HEIGHT
AND LOOPER TIMING ................................................................................ 47
(1) MO-6700D SERIES ....................................................................................................47
6. TROUBLES AND CORRECTIVE MEASURES ........................................... 48
7. DIMENSIONS OF TABLE ............................................................................ 60
(1) Semi-sunken type .....................................................................................................60
(2) Semi-sunken type (synchronizer is used)..............................................................61
(3) Fully-sunken type .....................................................................................................62
– 1 –
1. SPECIFICATIONS
(1) MO-6700D SERIES
No. Item Specifications
1 Model MO-6704D MO-6714D MO-6716D
2 Description 1-needle Overlock 2-needle Overlock 2-needle Safety stitch
machine machine machine
3 Stitch type F. S. T. JIS E13 JIS E24 JIS E13+D12
(USA standard : 504) (USA standard : 514) (USA standard : 516)
4 Sewing speed 6000rpm
5 Stitch length 0.8 to 4mm 1.5 to 4mm
6Needle gauge 2.0, 3.2mm 3.2, 4.8mm
7Overedging width 1.6, 3.2, 4, 4.8mm 2.0, 3.2, 4mm 3.2, 4, 4.8, 6.4mm
8 Differential feed ratio Gathering 1 : 2 (Max.1 : 4), Stretching 1 : 0.7 (Max.1 : 0.6)
9 Needle bar stroke 24.5 mm (30P for light to medium-weight materials),
25.5 mm (40H for medium to heavy-weight materials)
10 Needle tilt angle 20°
11
Needle bar mechanism
Upper and lower needle bar bushing type
12 Needle ORGAN DC X 27 (Standard) (DC X 1 can be used as well.)
13 Presser lifting amount 7.0mm 6.5mm 7.0mm
14 Presser foot pressure 49N (5kg)
15
Stitch adjusting method
By pushbutton
16 Upper knife Flat knife
17
Differential feed adjustment
By lever with micro adjustment mechanism
18 Weight 28kg
19 Lubrication Automatic geared lubrication system and grease charge
20 Lubricating oil JUKI MACHINE OIL 18 (Equivalent to ISO VG 18) Product No.: MML018900CA
21 Grease Exclusive grease (Part No. 23640204)
22 Needle cooler Optional
23 Needle thread cooler Optional
24
Micro presser lifting device
Provided as standard
25 Motor 2P 400W
*1. Grease should be supplied to the needle bar system and upper looper system.
– 2 –
2. MODEL NUMBERING SYSTEM
MO-6700D SERIES MODEL NUMBERING SYSTEM
1 2345678910111213 14 15 16 17 18 19 20 21 22 23 24 25 26
MO67 D /
3 to 6 Model classification
6704 1-needle 3-thread overlock
6705 Blind-hemming
6712 2-needle, 4-thread imitation safety stitch
6714 2-needle 4-thread overlock
6716 2-needle 5-thread safety stitch
6743 3-needle 6-thread safety stitch
6745 2-needle double chain stitch
7Type classification
D Semi-dry head
8 Needle gauge classification
0 1-needle
B 2.0mm
D 3.2mm
F 4.8mm
1 4.8+2.0mm
2 3.2+2.0mm
9 Overedging width classification
A 1.6mm
B 2.0mm
D 3.2mm
E 4.0mm
F 4.8mm
H 6.4mm
10 Feed dog classification
42-row
51-row
63-row
11 Material classification
(classification applied to handling material and cloth)
1 Extra light- to right-weight material Light weight material such as dress shirt
2
3Light- to medium-weight materials General fabrics
4 Meduim- to heavy-weight materials Exclusive for knit such as sweater
5Medium weight material such as denim to heavy weight material
12 Application classification
(classification of application based on work and process)
0 Standard
1 For blind hemming
2 For ruffling
4 For tape attaching
5 For rolled hemming
6 For tape feeding
*
*
The asterisk (*) indicates 3-needle type.
– 3 –
13 Special machine classification
(special classification of machine,
structure and specs. other than gauge set)
0 Standard
7 Upper looper high throw
F Swim suits
H Upper looper extra high lift
P Puckering prevention
15 to 22 Device and attachment classfication
G39/Q141 Presser for tape attaching (for sharp curve)/tape guide
L121 Blind stitch hemming attachment
S159 Swing-type gathering device (interlocked with pedal, for safety stitch machine)
S162 Swing-type gathering device (manual lever operated, for overlock machine)
N077 Clean finish top and bottom
E35 Overedging lug replace type throat plate
24 Place of destination
A Standard
DU.S.A and Japan
G China (in China)
25 Accessories type
A Standard
B Eouropa and U.S.A
G China (in China)
26 Table type
0 Fully sunken type
1 Semi sunken type
– 4 –
Model
DimensionADimensionBDimension
C
MO-6704D-0A -150 10.5 — —
MO-6705D-0 -210 10.5 — —
MO-6704D-0 -300 10.5 — —
MO-6704D-0 -307 10.5 — —
MO-6704D-0 -40H 11.3 — —
MO-6704D-0F6-50H 11.3 — —
MO-6714D-B - 7 10.5 9.1 —
MO-6714D-B - H 11.3 9.9 —
MO-6712D-DF6-50 11.0 9.4 —
MO-6714D-B -30P 10.5 9.1 —
MO-6716D- -300 10.5 — 9.8
MO-6716D-FF6-307 10.5 — 9.8
MO-6716D- - 11.3 — 10.6
MO-6716D- -30P 10.5 — 9.8
A
B
10
°
6704D
6705D
6712D
6714D
6716D
When the needle(s) is in the highest position, the needle height from the throat plate surface should be as
shown below.
3. STANDARD ADJUSTMENT
(1) Adjusting the needle height
The needle entry point should be such that the distances listed below are provided between the needle slot
edge of the throat plate and the center of needle.
(2) Positioning the throat plate
(Unit : mm)
The adjustment of needle height for the 2-needle overlock machine should be
made in reference to the left needle.
(Unit : mm)
Overlock side A 1.3
Double-chainstitch side B 1.0
For 30P
(Safety stitch machine)
4 H
50H
A
A
B
C
A
Standard Adjustment
Standard Adjustment
1-needle overlock
machine
2-needle overlock
machine
Safety stitch
machine
– 5 –
Needle driving shaft
1) Take off the upper cover, loosen setscrew of needle driving forked
crank and move needle driving forked crank up or down to adjust
the needle height.
(Caution) Do not fully loosen the setscrew of the needle driving
forked crank .
If the needle driving forked crank has got out of position
laterally when its setscrew was loosened, fully loosen the
setscrew and turn pulley to allow the forked crank to turn
until it settles by itself. Then tighten the setscrew to fix
the forked crank at that position.
o Any other needle height than
specified here will badly affect the
action of the lower looper, the
timing for catching the upper
looper thread, etc.
o Improper lateral position of the
needle driving forked crank will
cause seizure, play, or other
troubles.
o Improperly positioned throat plate
with cause needle breakage,
contact of the needles will the
throat plate, or other troubles.
1) Loosen setscrews of throat plate base and move throat plate
base back and forth to adjust dimension A or B.
Adjustment Procedure Results of Improper Adjustment
Adjustment Procedure Results of Improper Adjustment
– 6 –
(3) Installing position of the needle clamp
Needle clamp connecting stud should fit with the bottom end of needle bar or be spaced within 0 to 0.5
mm.
(4) Adjusting the length of the lower looper holder (Applicable only to MO-6716D series)
The center-to-center distance should be 26 mm.
At this time, the clearance between the end surface of the arm and the neck of the ball should be 3.5mm.
26mm
3.5mm
Butt the needle clamp with the
bottom end of the needle bar.
0 to 0.5mm
Standard Adjustment
Standard Adjustment
– 7 –
1) Loosen setscrew and adjust, by slightly turning needle clamp ,
the clearance provided between the right-hand side needle and the
lower looper (for 2-needle overlock machine) and the clearance
provided between the needle hole in the throat plate and the needle
(for safety stitch machine).
o If the clearance provided
between the needle and the
looper is excessive, the needle
thread will be likely to skip at the
time of tucking.
o If the clearance provided
between the needle and the
looper is insufficient, the needle
will break or the looper blade
point will be damaged causing
thread breakage.
1) Loosen setscrew of the lower looper holder from the rear of the
frame.
Since it is difficult to accurately measure the center-to-center distance,
perform adjustment to provide a 3.5 mm distance between the end
surface of the arm and the neck of the ball as illustrated.
o Increasing the center-to-center
distance will give a smaller stroke
of the double chain looper or
lower looper, and decreasing the
distance will give larger stroke.
Adjustment Procedure Results of Improper Adjustment
Adjustment Procedure Results of Improper Adjustment
– 8 –
1) Returning amount of the lower looper
The distance between the blade point of the lower
looper and the center of the needle should be as
follows when the lower looper is at the extreme
left of its stroke.
(5) Adjusting the lower looper
Model
MO-6704D-0A -150 4.0
MO-6705D-0 -210 4.0
MO-6704D-0 -300 3.8
MO-6704D-0 -307 3.8
MO-6704D-0 -40H 3.8
MO-6704D-0F6-50H 3.8
MO-6714D-B - 7 3.8
MO-6714D-B - H 4.0
MO-6712D-DF6-50 2.2
MO-6714D-B -30P 3.8
MO-6716D- -300 3.8
MO-6716D-FF6-307 3.8
MO-6716D- - 3.8
MO-6716D- -30P 3.8
(Unit : mm)
0.01 to 0.1 mm
Dimension
J
J
K
(66.9±0.2mm)
Standard Adjustment
1-needle overlock
machine
2-needle overlock
machine
Safety stitch
machine
2) Clearance between the lower looper and the needle
The clearance should be 0.01 to 0.1 mm.
4 H
50H
– 9 –
o Excessive return of the lower
looper tends to cause stitch
skipping when filament thread is
used.
o Insufficient return of the lower
lopper tends to cause needle
thread stitch skipping when spun
thread is used.
o Excessive clearance will often
cause needle thread stitch
skipping.
o Insufficient clearance will cause
needle breakage due to the contact of the looper with the needle,
or produce scratches on the
blade point of the looper, leading to needle thread breakage or
other troubles.
1) Returning amount of the lower looper
1
Loosen setscrew of lower looper support arm and adjust lower
looper to make adjustment of the returning amount.
(Referential information)
1. Radius K of lower looper will be 66.9 mm when the lower
looper is inserted into lower looper support arm until it contacts with stopper pin and then is fixed.
2. The rocking angle of the lower looper will be 26°.
2) Clearance between the lower looper and the needle
1
Loosen setscrew of lower looper support arm to the extent that
it is temporarily tightened. Then finely adjust the longitudinal position
of the looper using fine adjustment screw .
2
Turn fine adjustment screw clockwise to move lower looper away
from the needle.
Turn the screw counterclockwise to move lower looper closer to it.
Adjustment Procedure Results of Improper Adjustment
– 10 –
MO- 6704D - 0E to 0F - 4 H
MO- 6714D - BB6 to BE6- 30P
BD4 to BE4
BD6 to BE6
MO- 6716D - - 30P
D
F
(6) Position of the upper looper guide
Vertical position : To be in close contact with the frame guide surface.
Laternal position : To be pressed against the upper looper guide support gauge .
13131909 13132006
Model
Dimension
G
MO- 6714D - - 4 H
(Unit : mm)
(Unit : mm)
Model
Dimension
G
(Unit : mm)
7 5.5
6
6.3 4.7
5.8
5.8
6.3
5.8
5.8
6
G
Marker dot
Frame guide surface
MO- 6716D - - 4 H
Standard Adjustment
Upper looper guide
support gauge
1-needle overlock
machine
2-needle overlock
machine
Safety stitch
machine
– 11 –
1) Fit upper looper guide support gauge over gauge fixing pin which
has been driven in frame and secure the gauge with an O ring.
Then position the gauge taking the marker dot engraved on it or the
chamfering direction as reference.
2) When installing upper looper guide support , press it against the
gauge while keeping the upper looper guide support into close contact with the frame guide surface, then tighten the screws.
(Caution) Refer to “4- (4) -1) – 7 Various sealantsî for the various
sealants.
o If the upper looper guide has
improperly positioned vertically,
it will cause oil leakage or
disturbed path of the upper
looper with resultant stitch
skipping.
o If the upper looper guide has
been inaccurately positioned laterally , it will cause stitch skipping,
or contact with the looper.
Adjustment Procedure Results of Improper Adjustment
– 12 –
(7) Positioning the upper looper holder
Model
MO- 6704D - 0E to 0F - 4 H 48.2
MO- 6714D - BB6 to BE6 - 30P 47.3
BD4to BE4
BD6 to BE6
MO- 6716D - - 30P 46.2
D
F
MO- 6714D - - 4 H 48.4
Dimension
F
The distance between the bottom surface of the frame and the upper end of the upper looper holder pin
should be as shown below when the upper looper holder is at the highest point of its stroke.
(Unit : mm)
Bottom surface of frame
53mm
F
0.2mm
0.2mm
MO- 6716D - - 4 H 48.2
Standard Adjustment
1-needle overlock
machine
2-needle overlock
machine
Safety stitch
machine
– 13 –
1) Loosen the setscrew of upper looper ball arm and setscrew of
the upper looper holder.
2) Adjust the clearances between upper looper bracket and upper
looper holder to approximately 0.2 mm respectively, and tighten
setscrew of the upper looper holder.
(Make sure that the upper looper holder smoothly moves together
with upper looper shaft .)
3) Then determine dimension F from the bottom surface of the frame to
the top surface of upper looper holder pin before tightening the
setscrew of upper looper ball arm .
(Caution) Replace upper looper holder according to the needle
gauge size.
o Inaccurately positioned upper
looper holder will cause
excessive projection of the upper
looper, resulting in stitch
skipping, or contact.
(Caution) To adjust the upper
looper ball arm, take
dimension
FF
FF
F
as stan-
dard.
Remember that the
projecting amount
and the height of the
upper looper should
eventually be properly adjusted. So,
confirm the dimensions related to the
upper looper.
Adjustment Procedure Results of Improper Adjustment
– 14 –
(8) Positioning the upper looper
1) Height of the upper looper
The distance between the throat plate surface and the blade point of the looper should be as follows when
the upper looper is at the extreme left of its travel.
2) Longitudinal position of the upper looper
1
The clearance between upper looper
and lower looper should be 0.05 to 0.2 mm when they cross
with each other.
2
The clearance between upper looper and needle should be 0.01 to 0.2 mm.
D
0.05 to 0.2 mm
0.01 to 0.2 mm
Model
DimensionDDimension
E
MO-6704D-0A -150 11.0 4.0
MO-6705D-0 -210 11.0 4.0
MO-6704D-0 -300 11.0 4.0
MO-6704D-0 -307 10.3 4.4
MO-6704D-0 -40H 11.3 4.4
MO-6704D-0F6-50H 11.3 4.4
MO-6714D-B - 7 10.3 4.4
MO-6714D-B - H 10.5 4.8
MO-6712D-DF6-50 11.0 3.6
MO-6714D-B -30P 10.3 4.4
MO-6716D- -300 11.0 4.0
MO-6716D-FF6-307 10.3 4.4
MO-6716D- - 11.3 4.4
MO-6716D- -30P 11.0 4.0
(Unit : mm)
EE
EE
E
E
D
E
D
Standard Adjustment
Throat plate
1-needle overlock
machine
2-needle overlock
machine
Safety stitch
machine
4 H
50H
– 15 –
1) Height of the upper looper
1
Set a hexagon wrench key onto setscrew at the end of upper looper
bracket to adjust height D.
2
When adjusting the height, pay attention also to the clearance produced between the upper looper and lower looper at the time of
their crossing.
2) Longitudinal position of the upper looper
1
Loosen setscrew at the top end of upper looper bracket to move
upper looper back or forth for positioning the clearance of 0.05 to
0.2 mm between upper looper and lower looper at the time of
their crossing or the clearance of 0.01 to 0.2 mm between upper looper
and needle .
o If the upper looper has been
positioned too high, an excessive
clearance will be produced
between the upper looper and
the needle. As the result, the
upper looper thread will fail to
catch the needle thread, and
stitch skipping occurs.
o On the contrary, if the upper
looper has been positioned too
low, the needle point will hit the
looper, causing needle breakage. Also the looper will touch
other component when the
presser foot goes up.
o Excessive clearance will cause
stitch skipping.
o Insufficient clearance will cause
the upper looper to come in contact with the lower looper.
Adjustment Procedure Results of Improper Adjustment
– 16 –
1.5 to 1.7 mm
(63.4 mm)
M
1) Returning amount of the double chain looper
The distance between the needle center and the blade point of the double chain looper should be 1.5 to 1.7
mm when the looper is at the extreme left of its travel.
2) Longitudinal motion (Avoid motion)
The standard minor axis of the elliptical motion should be :
3.0 mm.
Note : The avoid motion should be adjusted in accordance with Needle No.
3) Clearance between the double chain looper and the needle
The clearance should be 0.05 to 0.1 mm.
(9) Adjusting the double chain looper (Applicable only to MO-6716D series)
3.0 to 3.6 mm
0.05 to 0.1 mm
Standard Adjustment
Marker
Hole
Marker
A
B
– 17 –
1) Returning amount of the double chain looper
1
Loosen setscrew of double chain lopper driving arm to make
this adjustment.
2
Radius Mof the double chain looper driving arm will be 63.4 mm
when it is lowered until it comes in contact with stopper pin .
2) Longitudinal motion (Avoid motion)
1
Open the cover of the adjusting hole on the rear of the frame, loosen
setscrew , and put a Ø2 rod in the hole. Now, make the adjustment
by turning the rod back and forth.
Marker : This side
..... Minimum (for standard to thin needle)
A
Marker : Far side
..... Maximum (for thick needles)
B
3) Clearance between the double chain looper and the needle
1
Temporarily tighten setscrew in the double chain looper, and finely
adjust the longitudinal position of the double chain looper. Adjust the
clearance to 0.05 to 0.1 mm.
o Excessive return of the double
chain looper will cause frequent
stitch skipping when filament
thread is used.
o Insufficient return of the double
chain looper will cause frequent
thread stitch skipping when a
spun thread is used.
o If the avoid motion is too large,
triangle stitch skipping will often
occur.
o Insufficient avoid motion will
cause the needle point to hit the
looper, producing scratches on
the needle point or looper.
o Excessive clearance will cause
frequent needle thread stitch
skipping.
o Insufficient clearance will cause
to looper to hit the needle, leading to needle breakage or
scratches on the looper blade
point with consequent thread
breakage.
As observed
from this side
Adjustment Procedure Results of Improper Adjustment
Bad needle
entry
Good needle
entry
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