JUKI LK-1850 Series Quick start guide

UUKI
LK-1850 SERIES
High-Speed 1-Needle Cylinder Bed Lockstitch
Bar Tacking Machines
ENGINEER'S MANUAL
19
k
TOKYO JOKI INOUSTRIAL CO., LTD
FOREIGN TRADE BUSINESS DIV.
No. IV-19
1983.7
From the library of: Superior Sewing Machine & Supply LLC

PREFACE
This Engineer's Manual is written for technical personnel who are responsible for the service and
maintenance of the machine.
The Instruction Book for the machine intended for the maintenance personnel and operators at
a garment factory contains detailed operating instructions. This manual describes "Standard
Adjustment", "How to Adjust", "Effects of Adjustment", and various other information which
is not covered by the Instruction Book.
It is advisable to use the relevant Instruction Book and Parts Book together with this Engineer's
Manual when carrying out the maintenance of the machine.
From the library of: Superior Sewing Machine & Supply LLC

CONTENTS
1. SPECIFICATIONS 1
2. CAUTION IN RUNNING THE MACHINE BY HAND 2
3. STANDARD ADJUSTMENT FLOWCHART @
4. STANDARD ADJUSTMENT 3
(1) Height of the needle bar 3
(2) Adjustment of the feed cam 3
(3) Position of the stop-motion hook 5
(4) Stop-motion timing 5
(5) Adjustment of the changingpulley pressingplate 7
(6) Adjustment of the starting leverstopper 7
(7) Adjustment of the safety plate g
(8) Position of the work clamp foot g
(9) Height ofthe work clamp foot 11
(10) Position ofthe wiper H
(11) Adjustment ofthe tension release bar 13
(12) Position of the shuttle race spring 13
(13) Adjustment of the timing between the needle and the shuttle 1g
1) Timing of the needle bar 1g
2) Timing of the shuttle 1g
3) Clearance between the needle and the shuttle driver 1g
4) Clearance between the needle and the point of the shuttle 1g
5) Clearance between the needle and the shuttle race
(14)
(15)
(16)
(17)
(18)
(19)
(20)
(21)
(22)
15
Lateral position of the work clamp foot iy
Adjustment of the auxiliary knife driving cam
Position of the moving knife and the counter knife ig
Height of the moving knife and the counter knife
Tilt of the counter knife blade
19
Adjustment of the length of thread remaining on the needle 2i
Adjustment of the thread take-up spring 2i
Adjustment of the belt tension 23
Adjustment of the bobbin winder 23
5. OTHER PRECAUTIONS
25
(1) Configuration of the shuttle race ring 25
(2) How to remove the backlash of the shuttle driver shaft 25
(3) How to remove the backlash of the main shaft 25
(4) How to remove the backlash between the worm and the worm gear 27
(5) How to remove the backlash of the feed bracket
6. DISASSEMBLING &ASSEMBLING PROCEDURES AND PRECAUTIONS
27
29
11,
(1)
(2)
(3)
(4)
(5)
(6)
(7)
Disassembling the shuttle driver shaft 2g
Disassembling the main shaft
Disassembling the speed reducer
Disassembling the high speed pulley (asm)
Disassembling
the changing pulley •
Disassembling
the low-speed pulley
Assembling the pedal pressure decreasing unit
7. PARTSTO BE FIXED WITH LOCKTITE
8. PARTS TO BE FILLED
WITH GREASE
9. EXPENDABLE PARTS
(1) General ExpendableParts
(2) Expendable PartsTo Be Replaced Infrequently
(3) Parts Likely To Be Lost Or Damaged During Repair
10. PARTS FOR SUBCLASS MACHINES
(1) Parts For Changing The Numberof Stitches
(2)
Special Partsand Devices
(3) Modifying The Standard Machine To Subclass Machine
29
31
33
33
33
35
41
42
44
44
44
44
45
45
45
46
TROUBLES AND CORRECTIVE MEASURES 47
From the library of: Superior Sewing Machine & Supply LLC

1. SPECIFICATIONS
Description Standard
Subclass
Model
LK-1850
LK-1852-5
LK-1854-10
LK-1852-20
LK-185 2-30
LK-1854-40
LK-1854-6 LK-1852-3
LK-1854-4
LK-1852-1
LK-1854-11
LK-1852-2
AppUcationLaig(>size
bartacking
Large-size
bartacking
Attaching
belt loops
Attaching
belt loops
Attaching
belt loops
Attaching
belt loops Knit
goods
bartacking
Knit goods
bartacking
Buttonhole
bartacking
Buttonhole
bartacking
Small-size
bartacking
Small-size
bartacking
Sewing
speed
(spm)
Max.
(cotton thread)
2300 2300
2300 2300 2300
2300 2300
2300
2300
2300 2300 2300
Normal
(synthetic thread)
1800
1800
1800 1800
1800 1800
1800
1800
1800
1800
1800
1800
Stitch diagram
'wmm
1
42
m A A A 4
"i V V V vx WWWV^ 21
TA A A A S
bUUUUUVAl
riVVVVVV^
28
kwwi
Number of stitches
42
28
21
28
28
42
21
28 21
28
21
28
Bartacking mdth (mm)
1.5 ~3
1.5-3
0000
1.3-3
(Standard 2.5)
1.3-3
(Standard 2.5)
1.5-3
(Standard 2.5)
1.5 - 3
(Standard 2.5)
1.5-3
(Standard 2.5)
1.5-3
(Standrd 2.5)
Bartacking length (mm)
8~I6 8-16
6.5 ~ 14
(Standard 14)
6.5 ~ 14
(Standard 14)
13-25
(Standard 25)
18-35
(Standard 25)
4-8
(Standard 6.5)
4-8
(Standard 6.5)
4-8
(Standard 8)
4-8
(Standard 8)
4-8
(Standard 8)
4-8
(Standard 8)
Needle
DPx5
#14. #16
DPx5
#14,#16
DPx5
#14. #16
DPx5
#14,#16
DPx5
#14.#16
DPx5
#14. #16
DP X5 #11
DP X5 #11
DPx5
#14.#16
DPx 5
#14, #16
DPx 5
#14.#16
DPx 5
#14.#16
lift of piesserfoot (mm)
Max. 17 Max. 17 Max. 17
Max. 17
Max. 17
Max. 17 Max. 17
Max. 17
Max. 17
Max. 17
Max. 17
Max. 17
* The following specifications are common to both the standard and subclass models.
NeetOe bar stroke
41.2
Thread take-up link-type thread take-up
Shuttle race
Half-rotary shuttle race
(lubricatedthrough oil wick)
Adjustmentof bartacking
width & length Byfeed regulator lever(fixed by nut)
Thread trimmingsystem Threadspreader: Interlocked with main shaft,
Thread trimmer: Interlocked with lifter
Liftingsystem
One-pedal system: Pedal pressure decreasing
unit (Standard)
Two-pedal system: Forfoot-treadle type P
(option)
Wiper
Interlocked with lifter
Bobbin winder
Driven by belt
Drivingsystem
2-stage V belt speedreducingsystem
Safety device One-pedaldouble safety device
Lubrication
Lubricating oil: Juki New Defrix Oil No. 2
System: By centralized oil wick and
greasefilling
Motor
2()0W (single-or 3-phase)
Weight(kg)
42.5
(Cautions)
1) A madiina for attaching belt loops is to be installed sideways.
Refer to the figure at right and the table drawing on the last page
of this manual for installing the pedal shaft supplied with the
machine.
2) See the following table for proper use of the feed plate and work
clamp foot according to belt loop length.
Feed plate Work
damp foot
LK-1854-10
Part No. 13543608
Part No. 13544408
LK-1852-20 (Standard) Part No. 13543608
Part No. 13544408
LK-1852-30
Part No. 13545504
Part No. 13545603
LK-l 854-40 (Standard)
Part No. 13545504
Part No. 13545603
LK-185440
(25 mm or more)
Part No. 13547005
Part No. 13547104
3) Motorpulleyand belt (Theasterisked partsare available on specialorders)
Edge of table
Motor
, in Opening forbelt
Starting pedal shaft | /' [ ' |
Starting pedal lever J |
(Viewed from table bottom)
Fig. I
Frequency Sewingspeed Motor pulley
Part No.
Numerical mark
High-speedV belt Low-speed V
belt
50 Hz
2300 spm * 13531108 (For cotton thread)
50 - 2300 •MTJVM005000 (50")
MTJVM004600
46"
2000 spm *
13531207 (For cotton thread)
50 - 2000
*MTJVM004900 (49")
1800 spm
2300 spm
13531306
50 - 1800
60 - 2300
MTJVM004800 (48")
60 Hz
* 13531405 (For cotton thread)
• MTJVM004900 (49")
MTJVM004600
46"
2000 ispm *
13531504 (For cotton thread)
60 - 2000 • MTJVM004800 (48")
1800 spm
13531603
60 1800
MTJVM004700 (47")
From the library of: Superior Sewing Machine & Supply LLC

From the library of: Superior Sewing Machine & Supply LLC

3. STANDARD ADJUSTMENT FLOW CHART
Adjustment of
stop-motion mechanism
Positioning the
stop-motion hook
Adjusting the
stop-motion timing
Adjusting the
safety plate
Adjustment of
speed reducer
Adjusting the
chan^ng pulley
pressing plate
Adjusting the starting
lever stopper
Standard Adjustment Flow Chart
Adjusting of pedal
pressure decreasing unit
Removing the pedal
pressure decreasing
unit
Installing the pedal
pressure decreasing
unit
Adjustment of clamp
foot lifting mechanism
Positioning the
work clamp foot
Adjusting the height
of the work clamp
foot
Adjustment of
bartacking functions
Adjusting the lower deat
point of the needle bar
Adjusting the feed cam
Adjusting the
shuttle
race spring
Adjusting the needle
and shuttle driver
Adjusting the right
and left work clamp
feet
Adjusting the auxiliary
knife driving cam
Adjusting the moving
and counter knives
Adjusting the length
of thread remaining
on the needle
Adjusting the tension
of the thread take-up
spring
(Note) The solid lines with arrows ( , ,
and the broken lines with arrows ( -•) represent the need for
readjustment when independent adjustment has been made.
) show standard adjustment flow.
U.
Adjusting the bartack
ing width and length
@
Other adjustments
t-
Positioning the wiper
Adjusting
the teiuion
release bar
Adjusting the belt
tension
Adjusting the bobbin
thread winder
From the library of: Superior Sewing Machine & Supply LLC

4. STANDARD ADJUSTMENT
Standard Adjustment
(1) Height of the needle bar
The upper marker line engraved on the needle bar should be flush with the bottom end of the lower
needle bar bushing when the needle bar is at the lowest point of its stroke.
(Note) Perform this adjustment first before making any other adjustment.
Needle bar
Needle bar bushing (lower)
Upper marker line
Fig. 3
(2) Adjustment of the feed cam
Adjustment should be made so that the
feed is completed when the needle point
is 7 to 10 mm
(9/32" ~ 25/64") above
the throat plate surface.
(It is advisable to make this adjustment
during lateral feed). ^ ~ 10%
(9/32" ~ 25/64")
-3-
&>—
E3
Fig. 4
Fig. 5
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How to Adjust
1) Turn the drivingpulley by hand until the needle bar reaches the
lowest point of its stroke.
2) Remove the rubber plug from the face plate.
3) Loosen setscrew (T),and move the needle barup or down to
make the adjustment.
4) After adjustment, securely tighten setscrew (T) .
Loosen nut (T) andthencam guide pin . This will allow feed
cam (3) to be movedin the direction of rotation for adjustment.
• When the feed cam is turned in direction A, the feed timing
advances.
• When the feed cam is turned in direction B, the feed timing is
delayed.
%
® Fig. 6
(Caution)
Perform this adjustment first after the adjustment of the height of
the needle bar. Make sure to readjust stop-motion regulating cam
whenever the feed cam has been adjusted.
-4-
Effects of Adjustment
• Improper adjustment willcause
stitch skipping or thread breakage.
Whenit is adjusted to 7 mm
(9/32") or so, well-tensed
stitches will result.
Whenit is adjusted to 10 mm
(25/64") or so, protrusion of
the first stitch needle thread
onto the material surface will
be prevented when sewing with
asynthetic thread.
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Standard Adjustment
(Note)
Strictly follow the order of adjustment for (3) through (6) shown below.
(3) Position of the stop-motion hook
Perfonn adjustment so that a 3 mm (1/8") clearance is provided between the stop-motion hook and the
stop-motion cam when the machine runs at a low speed.
%
Fig, 7
Stop-motion
regulating cam
Stop-motion regulating
cam roller
Knife driving
cam 0.7 ~ 1. 2 %
Stop-motion hook
'3
'Wl
Thread trimmer
returning roller
Driving plate
3/64")
Stop-motion cam
,Knife driving
cam roller
0-0. 5% (1/64")
Fig. 9
Fig. 8
(4) Stop-motion timing
Performadjustment to make the stop-motion regulating cam roller drop from the low-speed point of the
stop-motion regulatingcam onto the stop motion point at the moment the top surfaceof the stop-motion
hook aligns withthecenterof the screw No. 1on the stop-motion cam at thelaststitchas shown in Fig.
12.
Screw No. 1
Stop-motion hook Stop-motion cam
Fig. 12
-5 -
Stop-motion regulating cam roller
£
Stop-motion regulating cam
Fig. 13
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How to Adjust
1) Turn the main shaftbyhandto obtainthestate shown in Fig. 7.
(low-speed running)
2) Remove the spring (2) and spring (D .
3) Loosen screw (T), and perform adjustment to allow a3 mm (1/8")
clearance between thestop-motion hookandthe knife driving
cam.
(Caution)
When tightening screw (l), be careful not to cause excessive axial
sticking.
Fig. 10 Fig. 11
Loosen three setscrews (D, and make adjustment within the slot.
-6
Effects of Adjustment
If the clearanceis adjusted to
3 mm (1/8") or less;
A neutral state will result when
the machine runs at low speed,
causing the machine to idle and
stop. Further, the clearance of
0.7 to 1.2 mm (45/64") ~
(3/64") between the knife
drivingcam and the knife driving
cam roller willgo at the time of
low-speedmachine running with
resultant striking noises. Also the
stop-motion cam will interfere
with the stop-motion hook at the
time of stop motion. (Fig. 8)
If the clearanceis adjusted to
3 mm (1/8") or more;
The pressure of spring will
become too high when the machine
mns at high speed, often causing
the machine to idle and stop. It
may alsolead to inadequate torque
at the start of high-speedrunning
with consequent reduction in
sewing speed.
Also,the thread trimmer returning
roller will interfere with the driv
ing plate, resulting in thread
trimming failure, (clearance : 0
to 0.5 mm
(1/64")) (Fig. 9)
• If later than screw No. 1;
The brake will not work, and
therefore a great stop-motion
shock will result.
Also, it may cause the machine
to stop at the first starting stitch.
• If earlier than screw No. 1;
The brake will work excessively,
causing a stop motion failure.
If the timing is extremely too
early, the stop motion will be
engaged one stitch earlier,
producing an abnormal sound.
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Standard Adjustment
(5) Adjustment of the changing pulley pressing plate.
The clearance A should be equal to clearance Bat the time ofstop motion. (A=B=0.4mm(l/64"))
(0.007") .
0 2% Changing pulley
j Low-speed pulley
fKTT
r\
High-speed pulley ^
B
0.4'
0.4% (1/64")
Fig. 14 Fig. 15
Changing pulley
pressing plate
(6) Adjustment of the starting lever stopper
Bring the starting lever into contact with the stopper screw and make adjustment so that the starting lever,
when pulled, will stop at the moment the clearance between the stop-motion
hook and the stop-motion
cam reaches3 mm (1/8") (refer to the previous clause(3)).
Starting lever
To be in contact with
stopper screw
Fig. 17
Stop-motion hook-
-7-
Stop-inotion cam
3% (1/8") I /
tn
Fig. 16
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How to Adjust
1) Place the stop-motion hook in the stop-motion position.
2) Loosen nut (T) and then screw Q).
3) Securely tighten screw (3).
4)
Gradually tighten screw untilequal clearances are provided
at A and B. (A = B= 0.4 mm(1/64"))
Push down the starting lever and make adjustment so that the
starting lever comes in contact with the stopper screw when the
clearance between the stop-motion hook and the stop-motion
cambecomes3 mm (1/8") (refer to (3) Position of the stop-motion
hook), then lock it using the nut.
-8-
Effects of Adjustment
If A si larger than 0.4 mm (1/64")
while B is smaller than 0.4;
Heat may be generated due to
the contact between low-speed
pulley and the changingpulley,
or low-to-highspeed changing
feed timing may not synchronize
with the motion of the needle
bar, often causing the machine
to idle and stop.
Also, the machine may fail to
reach the high sewingspeed.
If A is smaller than 0.4 mm
(1/64") while B is large than 0.4;
An inadequate torque may be
caused in low-speed operation, or
heat may generated due to the
contact between the changing
pulley and the high-speed pulley.
If A + B + C is larger than the
specified value;
The machine may stop at the time
when the sewing speed is changed
from low speed to high speed in
sewing extra heavy-weight material
or the like.
If the adjusted value is larger than
3 mm (1/8"), the machine will be
put into idling state and stop at
the time of starting.
If the adjusted value is smaller
than 3 mm (1/8"), there will be
no allowance in the slot of the
starting lever when the machine
runs at high speed, causing the
lever to bind.
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Standard Adjustment
(7) Adjustment of the safety plate
Adjust the safety plate andthe work clamp foot lever sothat a lateral clearance of0.2 to 0.5 mm
(0.007" ~ 0.019")is provided forA,anda longitudinal clearance of 1.5 to 2.5 mm (1/16"~
3/32") for B.
Work clamp foot lifting lever
Safety plate
@
!S!
Down
Fig. 18 Fig. 19
(8) Position of the work clamp foot
Tum the main shaft by hand and perform adjustment to equalize the both clearancesA between the needle
and the work clamp feet in the longitudinal feed.
Alsomake equal the both clearancesB between the feed plates and the work clamp feet.
Feed bracket
Feed plate
Work clamp foot
B B
Fig. 20
-9-
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How to Adjust
Loosen setscrew (T) to make adjustment.
After adjustment, securely tighten the setscrew.
1) Loosen screw 0 and make adjustment of the work clamp
foot within the slot in the feed bracket.
2) Loosen screw 0 and adjust the position ofthe feed plate
by the slot in the feed plate.
-10-
Effects of Adjustment
If the clearance A is extremely
small, the work clamp foot will
not go up.
If the clearance B is smaller than
the specified value, the safety
plate and the work clamp foot
lifting lever will interfere with
each other, causing a stop motion
failure.
If the clearance B is zero, the
machine can not be started.
If the clearance A is too large,
the wiper and the thread trimmer
willbe actuated before stop
motion, causing the wiper to
interfere with the needle, or the
thread trimmer to cut the needle
thread to remain on the needle
too short with consequent slip
page of the thread from the needle
at stitching start.
If the two clearances A are not
equal, either work clamp foot
may interfere with the needle,
leading to needle breakage during
longitudinal feed.
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Standard Adjustment
(9) Height of the work clamp feet
Remove the top cover, and adjust the height of the work clamp feet by the screwlocated at the center of
the frame.
The maximum lift of the work clamp feetis 17mm(43/64").
L-shaped wrench
1 7
(10) Position of the wiper
Fig. 21
j/r^
r\
A
The clearancebetween the wiper and the needle should be 1.5 mm (1/16") or more at the time
when the wiper passes by the needle point.
(The needle is in stationary state at the time of stop motion.)
o
1.5 (1/16")
j ;! 1
•czi
Height of the work clamp feet
Fig. 22
-11 -
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How to Adjust
Stop the machine with the work clamp feet up, and loosen screw
(D to make adjustment.
If the right and left work clamp feet are not levelled, perform
further adjustment using screw @ .
Adjust the position of
the wiper by screw (T) .
To move the wiper,
move starting lever (2)
up and down, and turn
pulley (3) by hand.
Be sure to bring the
stop-motion cam into
contact with A of the
stop-motion hook as
shown in Fig. 24 when
making this adjustment. Fig. 23
Stop-motion hook stop-motion cam
Fig. 24
-12-
Effects of Adjustment
If the work clamp feet are too
high, they will interfere with the
wiper when the wiper is actuated.
If screws @ aretoo low, the
feed bracket will interfere with
the loweringshaft. (Point A)
If the clearance is smaller than
1.5nun (1/16");
The wiper will interfere with the
needle point, resulting in needle
breakage or scratches on the
needle.
If the clearance is much larger
than 1.5mm(1/16"), the needle
clamp screw will hit the wiper
when the needle bar goes down.
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Standard Adjustment
(11) Adjustment of the tension release bar
Tension release bar (3) should project 4 mm (5/32") from the surface of supporter with the work
clamp feet up when the machine stops.
L-shapedwrench "g"
Tension lever
Fig. 25
(12) Position of the shuttle race spring
The shuttle race spring should be evenly positioned laterally with respect to the needle entry point, and it
should be positioned longitudinally sothat the rear edge ofthe needle aUgns with corner Aas shown below.
(Note)
Presence of any scrathes on area B may cause breakage of the bobbin thread. Grind and smooth out
scratches If any.
Fig. 26
- 13 -
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How to Adjust
Withthe machine in stationary state, remove the top cover
and the face cover, and loosen screw (T) to make adjustment
with the work clamp feet up.
Removethe feed bracket, feed plate and throat plate, then
perform adjustment using screw (T) .
(Note)
The lateral position of the shuttle race spring is affected also
bythe locking position of setscrew (^.
Fig. 27
-14-
Effects of Adjustment
If the projection of the tension
release bar is smaller than 4 mm
(5/32"); The tension discswill be
left released during machine
operation. If the projection is
muchsmallerthan 4 mm (5/32"),
tension
release bar (3) willcome
off supporter when the work
clamp feet begins to go up and
consequently the work clamp
feet fail to go up. Also, the
tension discs will not be released.
If the projection of the tension
release bar is larger than 4 mm;
The end of tension release bar(3)
will hit the face cover when the
work clamp feet go up, producing
a loud noise. Also, the thread
will not be released at the time
of thread trimming, and as a
result, the needle thread will be
cut extremely short.
Lateral or longitudinal deviation
of the shuttle race spring will
cause the needle thread to bite
into the shuttle race.
If the shuttle race spring is
positioned excessively in the
rear, the moving knife may fail to
catch the needle thread.
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Standard Adjustment
(13) Adjustment of the timing between the needle and the shuttle
1) Timing of the needle bar
Theneedlebar goesup from the lowest point of its stroke until the lowermarker line engraved on the
needlebar is flushwith the bottom end of the needle bar bushing(lower). (Fig. 28)
2) Timing of the shuttle
Whenthe state is as described in the above 1), the center of the needle coincideswith the point of the
shuttle at A. (Fig. 29)
3) Clearance between the needle and the shuttle driver
Whenthe state is as described in the above 2), there should be no clearance between the needle and the
shuttle driver. (Fig. 30)
4) Clearance between the needle and the point of the shuttle
Whenthe state is as described in 2), the clearance Bbetween the needle and the point of the shuttle
should be 0.05 to 0.1 mm(0.001" ~ 0.004")- (Fig- 31)
5) Clearance between the needle arid the shuttle race
The clearance between the side face of the needle and the shuttle race should be 7.5 mm(19/64"). (Fig. 32)
1) Timing of the needle bar 2) Timing of the shuttle
Shuttle
Needle bar
Needle bar bushing (lower)
'0
Fig. 28
Lower marker line
3) Clearance between the needle and
the shuttle driver
Shuttle driver
Fig. 30
5) Clearance between the needle
and the shuttle race
7.5 % (19/64")
Shuttle race
Fig. 32
15-
CD © (D
Fig. 29
0.3-0.5%
(0.011"-0.019")
4) Clearance between the needle and
the point of the shuttle
Fig. 31
0.0 5-0.1%
(0.001"-0.003")
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How to Adjust
1) Referring to Standard Adjustment (1) Height of the needle bar,
make the lower marker line engravedon the needle bar flush
with the bottom end of the bushing.
2) and 3) Loosen setscrew 0 of the shuttle driver, and adjust
the rotational and longitudinal directions of the shuttle driver.
(Caution)
Ensure to turn the shuttle in the arrowed direction as shown in
Fig. 29 when adjusting the timing of the shuttle.
4) Loosensetscrew (4) of the shuttle race, and turn eccentric
shaft (D to make adjustment.
5) Loosen setscrew 0 to perform adjustment.
Enoughcare should be exercised when performing the
adjustmentdescribed in 4), namely the adjustmentof the
clearancebetween the needle and the point of the shuttle.
(Note)
The clearance in the rotational direction between the shuttle
and the shuttle driver should be 0.3 mm to 0.5 mm (0.011
0.019") as shown in Fig. 29.
Strike points C or D for adjustment.
After adjustment, check that point C is evenly spaced
vertically with respect to the shuttle.
Fig. 33
-16-
Effects of Adjustment
1) and 2) Slightly reduce the height
of the needlebar (upper marker
line) for floppy material, and on
the contrary, slightly increase the
height for heavy-weightmaterial
to adjust the timing of the
shuttle.
(For prevention of stitchskipping)
3) If the clearance is more than 0
mm, the needle will be bent in
the direction of the shuttle point,
causing scratches on the shuttle
point and the needle. On the
contrary, however, excessive
contact between the needle and
the shuttle driver may cause
stitch skipping.
4) If the clearanceis greater than
0.05 to 0.1 mm (0.001 ~ 0.003"),
stitch skipping will occur. If it is
smaller than the specifled values,
the needle strikes the shuttle point
and scratches occur, leading to
thread breakage or fine splits of
thread.
5) If the clearance is smaller than
7.5 mm(19/64") the needle
thread will not be fully spread,
often causingthe needle thread
to bite into the shuttle.
• If the clearance between the
shuttle drive and the shuttle is
greater than 0.3 to 0.5 mm
(0.011" ~ 0.019"), the shuttle
noise will be louder. On the
contrary, if the clearance is not
enough, poorly tensed stitches
will result when sewing with a
thick thread.
From the library of: Superior Sewing Machine & Supply LLC