JUKI MO-6000S series, MO-6900G series, MO-6900R series MO-6900J series Engineer's Manual

ENGINEER’S MANUAL

29355807

No.E350-01

Super-High-Speed Overlock Machine High-Speed Overlock Machine / Safety Stitch Machine

MO-6000S series MO-6900G series (for Extra-heavy-weight Materials)

High-Speed Variable Top Feed Overlock Machine

MO-6900R series MO-6900J series (for Extra-heavy-weight Materials)

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 described below 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”.

MO-6900S MO-6700S MO-6900G MO-6900R MO-6900J

Part No. Part No. Part No. Part No. Part No. 29351707 29351707 29351707 29356409 29363009 29351806 29352408 29352309 29356201 29362803

Model Name of part Instruction Manual Parts List

CONTENTS

1. SPECIFICATIONS ............................................................................................. 1

(1) MO-6700S SERIES ........................................................................................................... 1

(2) MO-6900S SERIES ........................................................................................................... 2

(3) MO-6900G SERIES........................................................................................................... 3

(4) MO-6900R SERIES........................................................................................................... 4

(5) MO-6900J SERIES............................................................................................................ 5

2. MODEL NUMBERING SYSTEM ....................................................................... 6

3. STANDARD ADJUSTMENT ............................................................................. 8

(1) Adjusting the needle height............................................................................................ 8

(2) Positioning the throat plate ............................................................................................ 8

(3) Installing position of the needle clamp ....................................................................... 10

(4) Adjusting the length of the lower looper holder (Applicable only to MO-6

16S / MO-6916R, G, J series)........................................... 10

(5) Adjusting the lower looper ........................................................................................... 12

1) Returning amount of the lower looper .................................................................................................... 12

2) Clearance between the lower looper and the needle ............................................................................. 12

(6) Position of the upper looper guide .............................................................................. 14

(7) Positioning the upper looper holder............................................................................ 16

(8) Positioning the upper looper........................................................................................ 18

1) Height of the upper looper ...................................................................................................................... 18

2) Longitudinal position of the upper looper................................................................................................ 18

(9) Adjusting the double chain looper

(Applicable only to MO-6

16S/MO-6916R, G, J series) .............................................. 20

1) Returning amount of the double chain looper......................................................................................... 20

2) Longitudinal motion (Avoid motion) ........................................................................................................ 20

3) Clearance between the double chain looper and the needle ................................................................. 20

(10) Adjusting the height and clearance of the needle guard......................................... 22

1) For 1-needle or 2-needle overlock machine ........................................................................................... 22

2) For safely stitch machine ........................................................................................................................ 22

(11) Adjusting the height of the feed dog ......................................................................... 24

(12) Adjusting the tillt of the feed dog............................................................................... 24

(13) Adjusting the differential feed ratio ........................................................................... 26

(14) Longitudinal position of the feed dog ....................................................................... 26

(15) Adjusting the presser foot.......................................................................................... 28

1) Adjusting the tilt of the presser foot ........................................................................................................ 28

2) Adjusting the micro-lifting mechanism of the presser foot ...................................................................... 28

(16) Positioning the upper knife arm shaft ....................................................................... 30

(17) Positioning the upper and lower knives, and available overedge widths.............. 30

1) Lower knife ............................................................................................................................................. 30

2) Upper knife ............................................................................................................................................. 30

3) Overdging width...................................................................................................................................... 30

(18) Resharpening of the knife .......................................................................................... 32

(19) Position of the thread cam (Applicable only to MO-6

16 series)........................ 32

1) Adjustment of the thread cam................................................................................................................. 32

2) Adjusting looper thread cam thread guides A and B and the looper thread cam nail............................. 32

(20) Adjusting the throat plate support............................................................................. 34

(21) Adjusting the feed mechanism cover presser.......................................................... 34

(22) Adjusting the looper cover ......................................................................................... 36

(23) Adjusting the cloth chip cover ................................................................................... 36

(24) Adjusting the needle mechanism............................................................................... 38

(25) Position of the upper looper lubrication pin............................................................. 40

1) Orientation of the lubricating pin ............................................................................................................. 40

2) Setting the lubricating pin ....................................................................................................................... 40

(26) Longitudinal momentum of the top feed dog (Top feed amount) ........................... 42

(27) Vertical momentum of the top feed dog.................................................................... 44

(28) Adjusting the height of the top feed dog................................................................... 46

(29) Locus cut of the top feed dog .................................................................................... 48

(30) Adjusting the longitudinal position of the top feed dog .......................................... 48

(31) Adjusting the lateral position of the top feed dog.................................................... 50

(32) Position of the motion of the top feed dog ............................................................... 52

(33) Adjusting the feed bar guides A and B...................................................................... 54

(34) Adjusting the top feed dog pressure......................................................................... 56

(35) Lifting amount of the top feed dog (when operating the pedal).............................. 56

(36) Height of the presser (pedal operation)..................................................................... 58

(37) Lifting amount of the top feed dog (when the presser lifting lever is operated) ... 60

(38) Position of the thread guides and the looper thread take-ups................................ 62

(39) Adjusting soft chain making mechanism.................................................................. 64

1) Replacing the parts with those exclusively designed for making soft chains ......................................... 64

2) Adjustment value .................................................................................................................................... 64

3) Important points in adjustment ............................................................................................................... 65

(40) Position of the thread guides and the looper thread take-ups of MO-6900G (J)... 66

4. ADDITIONAL INFORMATION AND PRECAUTIONS..................................... 68

(1) Thread tension............................................................................................................... 68

1) Strength of tension spring....................................................................................................................... 68

2) Springs used for each model. ................................................................................................................. 68

(2) Upper looper .................................................................................................................. 69

(3) Center-to-center distance of the upper looper holder ............................................... 69

(4) Caution in assembly...................................................................................................... 69

1) Application of sealant ............................................................................................................................. 69

2) Precautions to be taken with respect to the lubricating components...................................................... 71

(5) Kinds of motor pulleys, belts and frame support plate bolts.................................... 72

1) Motor pulleys and belts........................................................................................................................... 72

2) Pat No. of frame support plate bolt......................................................................................................... 73

(6) Inspection and replacement of the cartridge filter ..................................................... 73

5. ADJUSTMENT OF THE NEEDLE HEIGHT AND LOOPER TIMMING........... 74

(1) MO-6000 SERIES ........................................................................................................ 74

6. TROUBLES AND CORRECTIVE MEASURES............................................... 75

7. DIMENSIONS OF TABLE ............................................................................... 87

(1) Semi-sunken type.......................................................................................................... 87

(2) Fully-suken type ............................................................................................................88

−1 −

1. SPECIFICATIONS

(1) MO-6700S SERIES

No.

1 2

4 5 6 7 8

9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

Item Model Description

Stitch type F. S. T.

Sewing speed Stitch length Needle gauge Overedging width Differential feed ratio Needle bar stroke Needle tilt angle Needle Presser lifting amount Presser foot pressure Stitch adjusting method Upper knife Differential feed adjustment Weight Lubrication Lubricating oil Needle cooler Needle thread heat remover Micro presser lifting device Motor

7,000 rpm

MO-6704S

1-needle Overlock

machine JIS E13 (USA standard : 504)

–

1.6, 3.2, 4, 4.8 mm

7.0 mm

MO-6714S

2-needle Overlock

machine JIS E24 (USA standard : 514)

2, 2.4, 3.2 mm

3.2, 4, 4.8 mm

6.5 mm

MO-6716S

2-needle Safety stitch

machine JIS E13 + D12 (USA standard : 516)

1.5 to 4 mm

2, 3.2, 4, 4.8 mm

3.2, 4, 4.8, 6.4 mm

7.0 mm

Specifications

0.8 to 4mm

Gathering 1 : 2 (Max.1 : 4), Stretching 1 : 0.7 (Max.1 : 0.6)

24.5mm 20˚

ORGAN DC X 27 (Standard) (DC X 1 can be used as well.)

49N (5Kg)

By pushbutton

Flat knife

By lever with micro adjustment mechanism

28 kg

Gear-type automatic lubrication

* JUKI MACHINE OIL 18 (Equivalent to ISO VG 18)

Optional Optional

Provided as standard

2P 550W (In case of 7,000 rpm)

2P 400W (in case of less than 7,000 rpm)

* JUKI MACHINE OIL 18 (Equivalent to ISO VG 18)

Part No. : MML018900CA (900 m

−2 −

(2) MO-6900S SERIES

No.

1 2

4 5 6 7 8

9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

Item Model Description

Stitch type F. S. T.

Specifications

MO-6904S

1-needle Overlock

machine JIS E13 (USA standard : 504)

8,500 rpm

–

1.6, 3.2, 4, 4.8 mm

7.0 mm

MO-6914S

2-needle Overlock

machine JIS E24 (USA standard : 514)

2, 2.4, 3.2 mm

3.2, 4, 4.8 mm

6.5 mm

MO-6916S

2-needle Safety stitch

machine JIS E13 + D12 (USA standard : 516)

1.5 to 4 mm

2, 3.2, 4, 4.8 mm

3.2, 4, 4.8, 6.4 mm

7.0 mm

Gathering 1 : 2 (Max.1 : 4), Stretching 1 : 0.7 (Max.1 : 0.6)

24.5mm 20˚

ORGAN DC X 27 (Standard) (DC X 1 can be used as well.)

49N (5Kg)

By pushbutton

Flat knife

By lever with micro adjustment mechanism

28 kg

Gear-type automatic lubrication

* JUKI MACHINE OIL 18 (Equivalent to ISO VG 18) Provided as standard (Excluding some of subclass machines) Provided as standard (Excluding some of subclass machines)

Provided as standard

2P 550W (In case of not less than 7,000 rpm)

2P 400W (In case of less than 7,000 rpm)

8,000 rpm

0.8 to 4mm

* JUKI MACHINE OIL 18 (Equivalent to ISO VG 18)

Part No. : MML018900CA (900 m

−3 −

(3) MO-6900G SERIES

No.

1 2

4 5 6 7 8

9 10 11 12 13 14 15 16 17 18 19 20 21 22 23

Item Model Description

Stitch type F. S. T.

Sewing speed Stitch length Needle gauge Overedging width Differential feed ratio

Needle bar stroke Needle tilt angle Needle Presser lifting amount Presser foot pressure Stitch adjusting method Upper knife Differential feed adjustment Weight Lubrication Lubricating oil Needle cooler Needle thread heat remover Micro presser lifting device Motor

Specifications

MO-6904G

1-needle Overlock

machine JIS E13 (USA standard : 504)

2.5 to 5 mm –

4.8, 10 mm Gathering 1 : 1.75 (Max.1 : 3.8) Stretching 1 : 0.6

MO-6914G

2-needle Overlock

machine JIS E24 (USA standard : 514)

2.5 to 4 mm

2.6 mm

6.4 mm Gathering 1 : 2 (Max.1 : 3.8) Stretching 1 : 0.7 (Max.1 : 0.6)

MO-6916G

2-needle Safety stitch

machine JIS E13 + D12 (USA standard : 516)

2.5 to 5 mm

4.8 mm

4.8, 6.4 mm Gathering 1 : 1.75 (Max.1 : 3.8) Stretching 1 : 0.6

6,000 rpm

28.8 mm 20˚

ORGAN DO X 5

Max. 8 mm

49N (5Kg)

By pushbutton

Flat knife

By lever with micro adjustment mechanism

28 kg

Gear-type automatic lubrication

* JUKI MACHINE OIL 18 (Equivalent to ISO VG 18) Provided as standard (Excluding some of subclass machines) Provided as standard (Excluding some of subclass machines)

Provided as standard

2P 400W

* JUKI MACHINE OIL 18 (Equivalent to ISO VG 18)

Part No. : MML018900CA (900 m

−4 −

(4) MO-6900R SERIES

No.

1 2 3

6 7 8

9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27

Item

Model

Description

Stitch type F. S. T.

Sewing speed

Stitch length Needle gauge Overedging width Differential feed ratio Needle bar stroke Needle tilt angle Needle Presser lifting amount Presser foot pressure Stitch adjusting method Upper knife Vertical amount of top feed dog Longitudinal amount of top feed dog Top feed adjusting type Differential feed adjustment Weight Lubrication Lubricating oil Needle cooler Needle thread heat remover Micro presser lifting device Motor

Specifications

MO-6904R

1-needle Overlock

machine JIS E13 (USA standard : 504)

–

3.2, 4, 4.8, 5.6 mm

7.0 mm

MO-6914R

2-needle Overlock

machine JIS E24 (USA standard : 514)

2 mm

3.2, 4 mm

6.5 mm

MO-6916R

2-needle Safety stitch

machine JIS E13 + D12 (USA standard : 516)

1.5 to 4 mm

3.2, 4.8 mm

3.2, 4, 4.8, 6.4 mm

5.5 mm

Gathering 1 : 2 (Max.1 : 4), Stretching 1 : 0.7 (Max.1 : 0.6)

24.5mm 20˚

ORGAN DC X 27 (Standard) (DC X 1 can be used as well.)

49N (5Kg)

By pushbutton

Flat knife

3.5 to 8.5 mm

1 to 7.5 mm (depending on the specifications of the respective machines)

By lever

By lever with micro adjustment mechanism

29 kg

Gear-type automatic lubrication

* JUKI MACHINE OIL 18 (Equivalent to ISO VG 18) Provided as standard (Excluding some of subclass machines) Provided as standard (Excluding some of subclass machines)

Provided as standard

2P 550W (In case of not less than 7,000 rpm)

2P 400W (In case of less than 7,000 rpm)

0.8 to 4mm

* JUKI MACHINE OIL 18 (Equivalent to ISO VG 18)

Part No. : MML018900CA (900 m

Feed type Vertical amount of top feed dog

7,000 rpm (longitudinal amount of top feed less than 6 mm)

6,000 rpm (longitudinal amount of top feed 6 to 8.5 mm)

−5 −

(5) MO-6900J SERIES

No.

1 2 3

5 6 7 8 9

10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27

Item

Model

Description

Stitch type F. S. T.

Sewing speed Stitch length Needle gauge Overedging width Differential feed ratio

Needle bar stroke Needle tilt angle Needle Presser lifting amount Presser foot pressure Stitch adjusting method Upper knife Vertical amount of top feed dog Longitudinal amount of top feed dog Top feed adjusting type Differential feed adjustment Weight Lubrication Lubricating oil Needle cooler Needle thread heat remover Micro presser lifting device Motor

Specifications

MO-6904J

1-needle Overlock

machine JIS E13 (USA standard : 504)

2.5 to 5 mm –

4.8 mm Gathering 1 : 1.75 (Max.1 : 3.8) Stretching 1 : 0.6

MO-6914J

2-needle Overlock

machine JIS E24 (USA standard : 514)

2.6 mm

6.4 mm Gathering 1 : 2 (Max.1 : 3.8) Stretching 1 : 0.7 (Max.1 : 0.6)

MO-6916J

2-needle Safety stitch

machine JIS E13 + D12 (USA standard : 516)

2.5 to 5 mm

4.8 mm

4.8, 6.4 mm Gathering 1 : 1.75 (Max.1 : 3.8) Stretching 1 : 0.6

28.8mm 20˚

ORGAN DO X 5

Max. 8 mm

49N (5Kg)

By pushbutton

Square knife

3.5 to 8.5 mm

2.7 to 7.0 mm (depending on the specifications of the respective machines) By lever

By lever with micro adjustment mechanism

29 kg

Gear-type automatic lubrication

* JUKI MACHINE OIL 18 (Equivalent to ISO VG 18) Provided as standard (Excluding some of subclass machines) Provided as standard (Excluding some of subclass machines)

Provided as standard

2P 400W

* JUKI MACHINE OIL 18 (Equivalent to ISO VG 18)

Part No. : MML018900CA (900 m

Feed type Vertical amount of top feed dog

6,000 rpm

2.5 to 4 mm

−6 −

2. MODEL NUMBERING SYSTEM

MO-6000 SERIES MODEL NUMBERING SYSTEM

MO6 / –

1 2 3 4 5 6 7 8 9 10 11 12 1314 15 16 17 18 19 20 21 22

4 Machine code

7 6700 series 9 6900 series

5. 6 Seam code 03 Splicing

04 1-needle 3-thread overlock (504) 05 For blind hemmong (505) 12 2-needle 4-thread mock safety stitch (512) 14 2-needle 4-thread overlock (514) 16 2-needle 5-thread safety stitch (516) 43 3-needle 6-thread safety stitch 45 2-needle double chainstitch

8 Needle gauge code

0 1-needle B 2.0 mm C 2.4 mm,

2.6 mm (for extraheavy-weight

materials) D 3.2 mm E 4.0 mm F 4.8 mm 1 4.8 mm + 2.0 mm

7 Basic specification code

S Standard G Extra heavy-weight materials R Variable top feed type

J Variable top feed type for

extra heavy-weight materials

9 Overedging width code

A 1.6 mm D 3.2 mm E 4.0 mm

F 4.8 mm H 6.4 mm M 10.0 mm N 18.0 mm

10 Feed dog code

4 2-row 5 1-row 6 3-row 7 4-row

12 Application code Classification based on type of operation

and process

0 Standard

1 For blind stitching

2 For gathering

4 For attaching tape

5 For binding

6 For binding tape D Splicing * E Car mattress

F Soft chain

* In case of the splicing, 13th figure is [1].

11 Material code Classification based on materials to be used

For light-weight materials such as shirts or the like Knit wear only General fabrics Knit wear only such as sweater or the like Medium-weight to heavy-weight materials such as denim or the like For heavy-weight materials Heavy-weight materials for jeans, car mattress, etc.

2 3 4

6 7

Extra light-weight to lightweight materials Light-weight to mediumweight materials Medium-weight to heavyweight materials

Heavy-weight to extra heavy-weight materials

* 6900 only

* * *

−7 −

13 Special machine code Special classification of machine, structure and

specification other than gauge set

0 Standard

6 Feed dog provided with a lip

7 Upper looper high throw type

F For swim suits H Upper looper extra high throw type M For zipper

1 For splicing

15 to 18 Device and attachment code

G02/Q141 Presser foot/tape guide for attaching tape

G39/Q141 Presser foot (for sharp curve)/tape guide for

attaching tape L121 Blind hemming ruler S159 Swing type ruffler (pedal-interlocking type for safety

stitch) S161 Swing type ruffler (Manual lever type for safety

stitch) S162 Swing type ruffler (Manual lever type for overlock) N077 Four-fold binder

* The general export specification is for Hong Kong, U.S.A., Japan and Singapore.

20 Machine head code

A Standard machine head

(Common to all specifications)

21 Accessory code

For general export

B For JE

G For China

22 Machine head code

0 Fully-sunken type 1 Semi-sunken type

The numberings after “–” (hyphen) of 19th figure will be used on and after April 1, 2002. They are not described on the catalogue or the like.

−8 −

Standard Adjustment

3. STANDARD ADJUSTMENT

(1) Adjusting the needle height

When the needle(s) is in the highest position, the needle height from the throat plate surface should be as shown below.

(2) Positioning the throat plate

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.

Note that “A=1.8” and “B=1.5” for MO-6 16S (R) - -60H, “A=1.6” and “B=1.3” for MO-69 G, J

(Unit : mm)

Overlock side A 1.3 Double-chainstitch side B 1.0

10˚

6 04

6 14

6 16

1-needle/

2-needle : left

10.5

11.3

11.0

11.3

10.5

11.3

10.5

11.3 13

10.5

11.3

9.8

15.4

14.4

15.4

14.1

2-needle : right

–

– –

9.4

9.9

9.1

9.9

– – –

9.9

9.9 – – – –

12.6 –

The adjustment of needle height for the 2-needle overlock machine should be made in reference to the left needle.

Model

MO- 6 04S(R) - - 0

- 6

50M MO- 6 04S - - H MO- 6 05S - - H

507

50F MO- 6 12S -CE4 -40H MO- 6 14S (R) -B -3 7

20H

40H MO- 6 16S(R)- - 0 MO- 6 16S(R)- - H MO- 6 16S(R)- -60H MO- 6943R - - 7 MO- 6 43S - - H MO- 6 45S - -360 MO- 6903G -0N6 -3D1 MO- 6904G(J)-0F6 -700 MO- 6905G -0M6 -7 0 MO- 6914G(J)-CH6 -700 MO- 6916G(J)-F 6 -700

(Unit : mm)

1-needle

overlock

machine

2-needle overlock

machine

Safety stitch

machine

MO-6900G, J

MO- 6 12S - -

MO- 6 14S (R) -B -

−9 −

Adjustment Procedures Results of Improper Adjustment

1) Take off the upper cover, loosen setscrew 2 of needle driving forked crank 1 and move needle driving forked crank 1 up or down to adjust the needle height.

(Caution) Do not fully loosen the setscrew 2 of the needle

driving forked crank 1. 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.

1) Loosen setscrews 2 of throat plate base 1 and move throat plate base 1 back and forth to adjust dimension A or B.

™ 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.

™ Improper lateral position of the

needle driving forked crank will cause seizure, play, or other troubles.

™ Improperly positioned throat

plate will cause needle breakage, contact of the needles will the throat plate, or other troubles.

Needle driving shaft

−10 −

(3) Installing position of the needle clamp

Needle clamp connecting stud 1 should fit with the bottom end of needle bar 2 or spaced within 0 to

0.5 mm.

Standard Adjustment

(4) Adjusting the length of the lower looper holder

(Applicable only to MO-6 16S / MO-6916R, G, J 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

3.5 mm.

3.5 mm

0 to 0.5 mm

Butt the needle clamp with the

bottom end of the needle bar.

26 mm

−11 −

1) Loosen setscrew 3 and adjust, by slightly turning needle clamp 4, 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).

™ 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.

™ 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.

Adjustment Procedures Results of Improper Adjustment

1) Loosen setscrew 1 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.

™ Increasing the center-to-center

distance will give a smaller stroke of the duble chain looper or lower looper, and decreasing the distance will give larger stroke.

−12 −

(5) Adjusting the lower looper

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.

2) Clearance between the lower looper and the needle

The clearance should be 0 to 0.1 mm.

Standard Adjustment

Dimension J

4.0

3.7

3.8

4.0

2.2

3.7

3.8

2.8

3.8

1.4

3.5

1.3

3.3

3.5

Model

Safety stitch

machine

(66.9±0.2 mm)

0 to 0.1 mm

1-needle overlock

machine

2-needle overlock

machine

MO-

6900G,J

(Only MO-69

△△

S,R,

G, J series)

(Unit : mm)

6 04S(R) 6

05S

MO- 6

04S(R)- -

MO- 6 04S - -

MO- 6

14S(R) - -3 7

MO- 6

16S(R) - -

0A5 15

MO- -0A4 to 0E4 -210

0D6 3 0F4 3 0 0F6 500 0H4 50M 0D4 to 0E4 4

0F6

50H BD4 to BE4 BD6 to BE6 BD6 to BF6 20H BE7 4

MO- 6

12S -CE4 -40H

50F

507

500 BE4

MO- 6

16S(R) -DD -

MO- 6 16S(R) -F 6 -60H MO- 6943R -

- 7

MO- 6

43S - - H MO- 6903G -0N6 -3D1 MO- 6904G(J) -0F6 -700 MO- 6905G -0M6 -7

0 MO- 6914G(J) -CH6 -700 MO- 6916G(J) -F

6 -700

MO- 6

12S -DF6 -

MO- 6

14S(R) -

4 H 5

−13 −

Adjustment Procedures Results of Improper Adjustment

™ Excessive return of the lower

looper tends to cause stitch skipping when filament thread is used.

™ Insufficient return of the lower

looper tends to cause needle thread stitch skipping when spun thread is used.

™ Excessive clearance will often

cause needle thread stitch skipping.

™ 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 2 of lower looper support arm 1 and adjust

lower looper 4 to make adjustment of the returning amount.

(Referential information)

1. Radius K of lower looper 4 will be 66.9 mm when the lower looper is inserted into lower looper support arm 1 until it contacts with stopper pin 3 and then is fixed.

2. The rocking angle of the lower looper will be 26˚. (MO-6 S, R) The rocking angle of the lower looper will be 32˚. (MO-69 G, J)

2) Clearance between the lower looper and the needle

MO-6700S Series 1 Loosen setscrew 2 of lower looper support arm 1 to the extent

that it is temporarily tightened. Now, make the adjustment by moving lower looper support arm 1 back and forth.

MO-6900S, R, G, J Series. 1 Loosen setscrew 2 of lower looper support arm 1 to the extent

that it is temporarily tightened. Then finely adjust the longitudinal position of the looper using fine adjustment screw 5.

2 Turn fine adjustment screw 5 clockwise to move lower looper

4 away from the needle.

Turn the screw counterclockwise to move lower looper 4 closer to it.

−14 −

Standard Adjustment

Model

6 04S(R) 6

05S

MO- 6

04S(R)- -

(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 1.

Safety stitch machine

1-needle overlock machine

2-needle overlock machine

5.8

Upper looper guide support gauge

13131909 13132006

Model

MO-6900G, J

6.3

5.8

4.7

5.5

6.3

5.8

4.2

11545100 12375606

7 5.5

6.3

4.7

4.2

Maker dot

(Unit : mm)

3 0 500

BE4

MO- 6

16S(R) -DD -

MO- 6 16S(R) -F 6 -60H

MO- 6943R -

- 7

MO- 6

43S - - H

MO- 6903G -0N6 -3D1

MO- 6904G(J) -0F6 -700

MO- 6905G -0M6 -7

MO- 6914G(J) -CH6 -700

MO- 6916G(J) -F

6 -700

Frame guide surface

Dimension G Dimension G

0A5 15

MO- -0A4 to 0E4 -210

0D6 3 0F4 3 0 0F6 500 0H4 50M 0D4 to 0E4 4

0F6

50H BD4 to BE4 BD6 to BE6

BD6 to BF6 20H BE7 4

MO- 6

12S -CE4 -40H

507

50F

MO- 6

04S - -

MO- 6

14S(R)- -3 7

MO- 6

14S(R)- -

MO- 6 12S -DF6 -

MO- 6

16S(R) - -

50H

−15 −

Adjustment Procedures Results of Improper Adjustment

1) Fit upper looper guide support gauge 1 over gauge fixing pin 3 which has been driven in frame 2 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 installin upper looper guide support 4, 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 sealants” for the

various sealants.

™ 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.

™ If the upper looper guide has

been inaccurately positioned laterally, it will cause stitch skipping, or contact with the looper.

−16 −

Standard Adjustment

(7) Positioning the upper looper holder

The distance between the bottom surface of the frame and the upper end of the upper looper holder pin 2 should be as shown below when the upper looper holder 1 is at the highest point of its stroke.

Bottom surface of frame

53 mm

0.2mm

Model

6 04S(R) 6

05S

MO- 6

04S(R)- -

Safety stitch machine

1-needle overlock machine

2-needle overlock machine

MO-6900G,J serise

Dimension F

45.0

46.2

48.2

47.3

48.4

46.8

46.9

46.2

48.2

48.4

47.3

48.4

51.2

50.7

51.7

49.3

48.8

(Unit : mm)

MO- 6 14S(R)- -3 7

MO- 6 14S(R)- -

MO- 6

12S -DF6 -

0A5 15

MO- -0A4 to 0E4 -210

0D6 3 0F4 3 0 0F6 500 0H4 50M 0D4 to 0E4 4 H 0F6

50H BD4 to BE4 BD6 to BE6 BD

to BF 20H

BE7 4

MO- 6

12S -CE4 -40H

507

50F

MO- 6

16S(R)- -

500

BE4

MO- 6

16S(R)- DD -

MO- 6 16S(R)-F 6 -60H

MO- 6943R -

- 7

MO- 6

43S - - H

MO- 6903G -0N6 -3D1

MO- 6904G(J)-0F6 -700

MO- 6905G -0M6 -7

MO- 6914G(J)-CH6 -700

MO- 6916G(J)-F

6 -700

5 H

MO- 6 04S - -

−17 −

Adjustment Procedures Results of Improper Adjustment

1) Loosen the setscrew of upper looper ball arm 3 and setscrew 5 of the upper looper holder.

2) Adjust the clearances between upper looper bracket 4 and upper looper holder 1 to approximately 0.2 mm respectively, and tighten setscrew 5 of the upper looper holder. (Make sure that the upper looper holder smoothly moves together with upper looper shaft 6.)

3) Then determine dimension F from the bottom surface of the frame to the top surface of upper looper holder pin 2 before tightening the setscrew of upper looper ball arm 3.

(Caution) Replace upper looper holder 1 according to the

needle gauge size.

™ Inaccurately positioned upper

looper holder will cause excessive projection of the upper looper, resulting in stitch skipping, or other troubles.

(Caution) To adjust the upper

looper ball arm, take dimension F as standard. 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.

−18 −

Standard Adjustment

(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 the upper

and lower loopers should be 0.1 to 0.2 mm when they cross with each other.

2 The clearance between the upper looper 3

and the needle should be 0 to 0.2 mm.

Model

Safety stitch machine

1-needle overlock

machine

2-needle overlock

machine

MO-6900G,J series

Dimension D

11.0

11.3

10.3

11.0

11.8

11.0

11.3

12.8

10.3

11.0

13.6

13.7

12.0

12.9

13.7

MO- 6

04S(R)- - 6

50M

MO- 6

04S - - H

MO- 6

05S - - H

BD4 to BE4

BD6 to BE6 BD

to BF 20H

BE7 4

MO- 6

12S -CE4 -40H

507 50F

MO- 6 16S(R) - - 0

MO- 6 14S(R)- -307

BE4

MO- 6 16S(R)- DD -

MO- 6 16S(R) - F 6 -60H

MO- 6943R

- - 7

MO- 6 43S

- - H

MO- 6903G -0N6 -3D1

MO- 6904G(J) -0F6 -700

MO- 6905G -0M6 -7 0

MO- 6914G(J) -CH6 -700

MO- 6916G(J) -F

6 -700

5 H

Throat plate

(Unit : mm)

MO- 6 12S -DF6 -

Lower looper

0.1 to 0.2mm

0 to 0.2mm

Needle

MO- 6 14S(R)- -

−19 −

Adjustment Procedures Results of Improper Adjustment

1) Height of the upper looper

1 Set a hexagon screwdriver onto setscrew 2 at the end of upper

looper bracket 1 to adjust height D.

2 When adjusting the height, pay attention also to the clearance

produced between the upper looper and the lower looper at the time of their crossing.

2) Longitudinal position of the upper looper

1 Loosen setscrew 2 at the top end of upper looper bracket 1

to move upper looper 3 back or forth for positioning the clearance of 0.1 to 0.2 mm between the upper looper and the lower looper at the time of their crossing or the clearance of 0 to 0.2 mm between upper looper 3 and the needle.

™ 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.

™ 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.

™ Excessive clearance will cause

stitch skipping.

™ Insufficient clearance will cause

the upper looper to come in contact with the lower looper.

−20 −

Standard Adjustment

(9) Adjusting the double chain looper

(Applicable only to MO-6 16S/6916R, G, J series)

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 2 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 (MO-6 16S, R).

3.5 mm (MO-6916G, J).

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.

3.0 to 3.6 mm

0.05 to 0.1 mm

MO-6916G, J series MO-6 16S, R series

Marker

Hole 5

63.2 mm

(63.4 mm)

1.5 to 2 mm

−21 −

Adjustment Procedures Results of Improper Adjustment

™ Excessive return of the double

chain looper will cause frequent stitch skipping when filament thread is used.

™ Insufficient return of the double

chain looper will cause frequent thread stitch skipping when a spun thread is used.

™ If the avoid motion is too large,

triangle stitch skipping will often occur.

™ Insufficient avoid motion will

cause the needle point to hit the looper, producing scratches on the needle point or looper.

™ Excessive clearance will cause

frequent needle thread stitch skipping.

™ 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.

1) Returning amount of the double chain looper

1 Loosen setscrew 2 of double chain lopper driving arm 1 to

make this adjustment.

2 Radius M of the double chain looper driving arm 1 will be

63.4 mm when it is lowered until it comes in contact with stopper pin 3.

3 For MO-6916G,J type machines, radius M will be 63.2 mm. 4 Adjust the tilt of double chain looper with setscrew 4. Adjust

the tilt to 1.6 mm.

2) Longitudinal motion (Avoid motion)

1 Open the cover of the adjusting hole on the rear of the frame,

loosen setscrew 5, 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 2 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.

MO-6916S,R series only 2 Turn fine adjustment screw 6 clockwise to move the double

chain looper away from the needle. Turn it counterclockwise to move the double chain looper closer to it.

Good needle entry

Bad needle entry

1.6mm

As observed from this side

−22 −

Standard Adjustment

(10) Adjusting the height and clearance of the needle guard

1) For 1-needle or 2-needle overlock machine

Make needle guard A lightly come in contact with the top end of needle (bend needle by 0 to 0.05 mm) when the blade point of the lower looper reaches the needle center. The clearance between needle guard B and the needle is 0.1 mm when the needle is at the lowest point of its stroke. The height of needle guard B is 1 mm from the throat plate bottom surface.

2) For safely stitch machine

The safely stitch machine has four needle guards, A, B, C and D. The needle guards A and B are positioned in the same manner as those for the overlock machine. The needle guard C should be positioned 5 mm below the throat plate bottom surface.

Needle guard A

(Traveling needle guard)

Light

touch

the

needle

guard

Needle guard B

Throat plate

1 mm

0.1 mm

Throat plate

5 mm

Lightly touches

0.1mm

−23 −

Adjustment Procedures Results of Improper Adjustment

1) For 1-needle or 2-needle overlock machine

1 Adjust needle guard A with setscrews 1 in the needle guard

so that it lightly comes in contact with the needle (bend needle by 0 to 0.05 mm) when the blade point of the lower looper reaches the needle center.

2 To adjust the clearance provided between needle guard B and the

needle when the needle bar is at the lowest point of its stroke, loosen setscrews 2 in the needle guard support and turn needle guard B to adjust the clearance to 0.1 mm.

3 Adjust the height of needle guard B to 1 mm from the throat plate

bottom surface with setscrew 3 in the needle guard.

2) For safety stitch machine

1 Loosen setscrews 4 in the needle guard, and adjust the

clearance provided between needle guard C and the needle so that it lightly comes in contact with the needle (bend needle by 0 to 0.05 mm).

2 Adjust the installing height of needle guard C to 5 mm with setscrew

3 in the needle guard.

3 Adjust the clearance provided between needle guard D and the

needle to 0.1 mm with setscrews 5.

(Caution) Check again the clearance provided between needle

guard B and the needle after adjusting the height of needle guard C.

™ Excessively close contact between

the needle guard A and the needles will lead to needle bend or stitch skipping.

™ A clearance left between the

needle guard A and the needles will cause the looper blade point to come in contact with the needles, leading to needle or blade point breakage, or other troubles.

™ If the needle guard B is too high,

thread loops will be damaged with resultant stitch skipping. Also, double chain loops will be affected, causing double chain stitch skipping.

™ If the needle guard B is too low,

the needle cooling felt will be lowered, resulting in deteriorated effect of the cooling and needle guard.

™ Excessive clearance between the

needle guard B and the needle will cause stitch skipping due to needle shake. On the contrary, insufficient clearance will cause the needle guards to catch the needles between them, leading to wear on the needle guards and scratches on the needles.

™ If the needle guard C is too high,

the needle thread loops will be damaged, and stitch skipping occur. If it is too low, the needle points will be crushed.

™ If the clearance between the

needle guard C and the needles is too large, the double chain looper blade point will come in contact with the needles, causing the breakage of the needles, causing the breakage of the needles or looper blade point.

No clearance left between them will

cause them to come in excessively close contact with each other, and wear on the needle guard and scratches on the needles will occur.

™ Excessive clearance left between

the needle guard D and the needles will cause stitch skipping due to needle shake, and insufficient clearance will cause the needle guards to catch the needles between them, leading to wear on the needle guards and scratches on the needles.

−24 −

Standard Adjustment

(11) Adjusting the height of the feed dog

The height of main feed dog 2 from the top surface of the throat plate 1 should be as follows when it is at its highest posion.

Auxiliary feed dog 4 is 0.5 mm lower than main feed dog 2.

(12) Adjusting the tillt of the feed dog

Model Dimension A

MO-6 00S Series 1.0

MO-6904G Series 1.3 MO-6914G Series 1.2 MO-6916G Series 1.1

0.5 mm

Tilt of the feed dogs when the feed dogs have come up most.

When the feed dog juts out the top surface of the throat plate

Needle

entry

Top surface of the throat plate

Feed dog is leveled.

Model Dimension A Dimension B

MO-6 00S Series 1.0 (1.2)

MO-6904G Series 1.3 (1.5) MO-6914G Series 1.2 (1.4) MO-6916G Series 1.1 (1.3)

(Unit : mm)

Front up

Needle

entry

(Unit : mm)

−25 −

Adjustment Procedures Results of Improper Adjustment

1) Adjust the height of main feed dog 2 to dimension A with setscrew 5.

2) Adjust the height of differential feed dog 3 with setscrew 7 so that there is no difference in level between main feed dog 2 and differential feed dog 3.

3) Adjust the height of auxiliary feed dog 4 with setscrew 6 so that it is 0.5 mm lower than main feed dog 2.

1) Use the tilt of the feed dog when it is in its highest position as a reference and adjust so that the feed dog is flush with the throat plate when the feed dog juts out the throat plate.

2) Feed bar shaft 8 consists of an eccentric shaft. Loosen setscrew 9 to perform adjustment.

When the marker line is set at middle

.....The feed dog will be flat.

When the marker line is set at bottom

.....The feed dog will be tilted with its front up (in the arrowed

direction).

When the marker line is set at top

.....The feed dog will be tilted with its front down.

(Caution) The marker line should be used just as the reference

since it slightly differs with that of each machine due to the disparity of the components. Confirm the accurate tilt of the feed dog by observing the feed dog itself.

™ If the feed dogs are too high, the

needles will be deflected and broken when sewing heavyweight materials. The feed dogs will tend to suffer scratches when sewing light-weight materials. Puckering will frequently occur.

™ If the feed dogs are too low,

insufficient feed power will result.

™ If the auxiliary feed dog is too

high, chain-off thread will be often jammed.

™ If the main feed dog and

differential feed dog are set at different heights, proper differential feeding action will be hindered.

™ When tilted with the front up

Good material catching will be

obtained.

™ When tilted with the front down

Uneven feed and puckering will

be effectively prevented.

+ 65 hidden pages

JUKI MO-6000S series, MO-6900G series, MO-6900R series MO-6900J series Engineer's Manual

Specifications and Main Features

Frequently Asked Questions

User Manual