JUKI MH-481 Instruction Manual
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Your JUKl Industrial Sewing Machine Model M H 4 8 1 and 484 are mainly featured by the follow-
ing functions:
MH-4
8 1
This model forms double chainstitch and provides reverse stitching at the end of sewing to
prevent revelling.
M H-4 84
In addition to the same function that MH-481 has, this model has the differential feed mech-
anism, by which both stretch and gather sewing are possible. A quite useful model to apply
stretch sewing to jersey and knitted fabrics and also to prevent general fabrics from puckering
and slipping. Special gether sewing attachments installing in MH-484 are available;
SO60 ..... Gather sewing attachment
SO61 ..... Intermittent gather sewing attachment
Since only the presser and feed mechanisms of model MH-484 are different from those of model
MH-481, this Instruction Manual is complied firstly t o explain the adjustments for model MH-481
including the common components to MH-484 and lastly to mention the particular adjustments for
model MH-484.
Before you start to use your JUKl Sewing Machine, throughly read this Instruction Manual for
correct and best use of it.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1. H O W T O S E T U F T H E M A C H I N E
1
1) How to install the oil reservoir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2) Motor pulley and the belt
1
2. HOW TO OPERATE THE MACHINE . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
-
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1) Cautions on operation
2
2) Lubrication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Adjusting the oil amount of the face part
. . . . . . . . . . . . . . . . . . . . . 3
On oil amount adjusting pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3) How to pass the needle thread . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4) How to pass the looper thread . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5) The thread tension.
6
. . . . . . . . . . . . . . . . . . . . . . . . .
Adjusting the needle thread tension
6
. . . . . . . . . . . . . . . . . . . . . . . . .
Adjusting the looper thread tension
6
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6) Presser foot and feed dog
6
Adjusting the pressing pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
On presser foot hand lifter
6
On chain-off thread presser . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
7) On stitch length
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Adjusting the stitch length
I
8) How to install the needle. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
9) How to install the silicon oil lubricant unit . . . . . . . . . . . . . . . . . . . . . 8
3. ADJUSTING THE MACHINE
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
. . . . . . . . . . . . . . . . . . . . .
1) Adjusting the presser foot and the feed dog
9
Adjusting the height of the presser bar
. . . . . . . . . . . . . . . . . . . . . . . 9
How to install the feed dog (MH-481) . . . . . . . . . . . . . . . . . . . . . . . . 9
Matching the needle and the feed dog . . . . . . . . . . . . . . . . . . . . . . . . . 9
. . . . . . . . . . . . . . . . . .
Adjusting the pressing pressure of the feed lever.
10
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2) On needle bar and needle.
10
Adjusting the height of the needle bar. . . . . . . . . . . . . . . . . . . . . . . . . 10
- -
3) Matching the needle and the looper
. . . . . . . . . . . . . . . . . . . . . . . . . 10
Adjusting the looper avoiding motion . . . . . . . . . . . . . . . . . . . . . . . . . 10
Matching the looper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Scooping amount of the looper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Clearance between the looper and the needle.
11
. . . . . . . . . . . . . . . . . . . . 11
4 ) Onthreadspreader . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
The timing of thread spreader against the needle
. . . . . . . . . . . . . . . . . 12
Position of the thread spreader latch . . . . . . . . . . . . . . . . . . . . . . . . . 12
Method of threhd spreader
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5) Needle guard and loop guide. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The timing of the needle guard
13
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 2
A"
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Position of the needle guard
13
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Position of the looper guide
13
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6) On looper thread cam
I 4
7)
On the position of the take-up thread tension lever. . . . . . . . . . . . . . . . . 14
8)
011 the frame thread eyelet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
4. OPERATION AND ADJUSTMENT O F MH-484 . . . . . . . . . . . . . . . . . . . . . 15
5. b1AINTI:NANCE O F TIIE MACHINE . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
6. MALI'UNCTIONS AN[) CORRECTIVE MEASURES . . . . . . . . . . . . . . . . . . 19
1. HOW TO SET UP THE MACHINE
1) How to install the oil reservoir
Operator's s ~ d e
Hinge side
Install the oil rcwrvolr In thc \lay that ~t I5
supported by lour cornrrs of the opening In
the table. Nail t\\.o rut~hrr rurhion\
1
to a
protruded edgc from thc tahle opening at
operator'\ cidc using nail? 2 and alw attach
two head-rest cu\h~on\ .(
t o 3 protrudeii
edge at thc far cnd Ihingc crdc) Uclng nail5
2 , and thc placv
i 1 1 l rc\crvolr
.1
on thc
cuthion.;.
I
l
2) Motor pulley and the belt
Mil-481 can \c\\ a t a ~ii,i\i~iiiin~
'PCCJ 111 llp
t o 5,500 \.p.n\.
Accordingly, uw ;I clutch rliotor ol 3 phahc
A(' 400W ( 1 '7 ill'). \ < c :I \'-l)t-lt 01 X1 typc.
*The relation between the lllotor pulley and the number u i !-ot;~tlun of 111~' r~ldchlnc IS \h~\\'ll
by the following table. (The effective diameter of the motor pullc\ I1lr;rI1\ tllc Jiarnetcr aS
measured from the center of the V-belt when ~t is wourld around th?, pullc).)
The most appropriate length of the V-belt IS 41 - - 43 incllc\.
..
-p~
j
1~t'sci.rlv~ 1
'
d~anlctci oi
Kcrl~arkh
. I n o t 0 I
'i
2. HOW TO OPERATE THE MACHINE
1 ) Cautions on operation
1). Do not operate the machine without filling up the oil reservoir with sufficient oil.
6j The direction of the rotation of the machme is toward the operator. Do not run the macline
in the reverse direction.
3 , The maximum rotational speed of the machine is up to 5,500 s.p.m. but for the first month
drop this speed to about 4,500 s.p.m.
After that, run the machine with appropriate speed depending on the nature of work,
lund of sewing material or sewing thread and capability of the operator.
2) Lubrication
I
Hefore runtilng the rnach~ne, fill up the
oil reyervolr w ~ t h JUKl New Defr~x 011
No. 1 up to the mdrk "HIGH".
I
L Watch and see that the 011 level does not
go under the "LOW" mark.
3
AS long as the oil reservoir is properly
filled up with the lubricating oil, you will
see the 011 splashing on the internal surface
of the oil sight window while the machine
is running. Since the oil sight window is
used only to check if the lubr~cating oil is
flowing or not, you do not have to worry
about the amount of oil appearing in it.
I-
(CAUTION)
In
order
to sufflc~ently lubricate those
machlnes whlch are newly set up or had not
been used for a long per~od of time let them
~ d l y run for about 10 minutes at a speed of
Adjusting the oil amount of the face part
When adjust~ng the oil amount to the needle
bar crank parts, remove the face plate and
adjust by rotating the oil amount adjusting
pin at the end of the lrlaln yhaft.
1. When the indicating point of the adjusting
pin comes near the needle bar crank pin.
the oil amount gets less and,
2. When the indicating point comes to the
opposite point of the crank pin, the oil
amount gets more.
CAUTION
The oil amount does not change immediately
after adjustment, so have this in mind when
adjusting the oil amount.
On oil amount adjusting pln
There 15 d cdrved groove on the o ~ l
ad~ubting
Needle bar crank 1
p ~ n
ac shown ~n the figure.
'Oil adjusting pin I
Arm shaft
Oil adjusting pin screw
Counterweight
1. When t h ~ s groove and the o ~ l ~ n p
hole of'
the main shaft are matched, the o~ling
amount becornes masimunl.
2. When this groove comes to the oppo.\ite
side of the oiling liolc. ttic oihng amount
hecomcs rnin~nlu~n.
3. The indicating p a n t of the adjusting pin
shows the sidc \v~thout the carved groove.
3) How to pass the needle thread
4) How to pass the looper thread
With the needle bar raised to its highest position, pass the thread in the order a. shown in
the figure.
1. Pass the thread to the needle hole toward the opposite side of the operator from the operator
side.
2. Pull out the thread which was passed through the needle about 10 cm (4"').
Pass the looper thread as shown in the figure.
1. Pass the looper thread through the looper thread guide plate as illustrated. When using a had-
twisted thread or when sewing with a large feed pitch, pass it through 2 holes to form a loop.
When sewing fine materials which tend 'to pucker, pass the thread through only one hole in
order to lessen the thread tension.
2. Pull the plate spring in the direction of arrow as shown in the lower figure, and the thread guide
@ will come up. As the close-up figure shows, the thread guide has two sets of thread holes;
the holes @ are used when a stitch is preferably formed with soft looper thread tension. a
stretchable thread is used or stitch length is more than 3 mm (1/8"), and the holes @ are used
when a stitch having a normal thread tension is prefered.
3. In passing the thread to the looper, use
a tweezer in the accessory box and
passing, pull it out 5 c& (2") from the
tip of the looper.
5) The thread tension
On chainoff thread presser
Adjusting the needle thread tension
I Rotate to right to rnakc lhe ' dy
1
tension stronger
!
6) Presser foot and feed dog
Adjusttng the preusrrq i~ressl re
-.
1S 111c pri~\\ur!: . I , ~ I L : Y I I I T ~
.(.re\\ \ \ turned lo
r~clit. thc i i r c \ \ ~ ! ~ ~ .
l i c ~ i . ~ ~ r ! i ~ ' . .
\iror1ger and if
I['\
tirrncd
to l~,ll I t i t , j3rc\..rrrc bccorncr
\vcdkcr. TIlc ,7t,~~:(f
i:\<,urc 1s 5 kg.
Adjusting the looper thread tension
Rotate to right to make the
3 n presser foot hand lifter
To stop the presser foot at the lifted position,
rotate the presser foot hand lifter either to
right or left.
To lower the presser fuot, manipulate the
knee lifter once and the presser foot will
return to its o r i ~ n a l
position.
7) On stitch length
Irrespective of high speed or low speed sew-
ing, a small chain-off thread presser is built-in
in the MH-481 model so that the chain-off
thread comes out easily. Conventional presser
foot for general lock stitch can be used if no
question is asked for chain-off thread.
Adjusting the stitch length
The stitch length of this model can be
adjusted by rotating the feed adjusting dial
on top of the feed lever.
The figures on the graduation scale is shown
in millimeter (mm).
1. Rotate the feed adjusting dial either to
right or left and
2. Match the wanted figure with the pin
coming out from the frame.
* The maximum stitch length is 4 rnm(5/32").
3. Lf the lever is pushed. it becomes reverse
sewing with thk standard pitch of 2mm
(5164").
4. If the position of the lever stopper 1s
raised, the pitch of the reverse
sewing becomes small.
5. If the position of the lever stopper IS
1
raised up further (loosen the nut and pull
I
8) How
the stopber up) and the lever is pushed,
it is possible to sew with normal sewing
to install the needle
with small stitch length.
Take advantage of this feature for bar-
tacking at the start of sewing or end of
sewing.
t
Feed direction
Q
I
,
0 0
0 0 0
Direction of the needle
hole
The designated needle is TV x 7, #9-#21.
For stabilizing the reverse sewing, do not
make the direction of the needle as shown
in the f i g u r e a .
3 ) How to install the silicon oil lubricating unit
j
MODEL MH-481 is provided with SILICON
OIL LUBRICATING UNiT for sewing with
I
synthetic or mixed synthetic thread.
I
AE shown in the figure left, install the silicon
1
o ~ l lubr~cation unit int the frame thread
I
eyelet.
i
I
I
i
3. ADJUSTING THE MACHINE
1) Adjusting the presser foot and the feed dog
How to install the feed dog
Adjusting the height of the presser bar
When the height or the direction of the
presser bar is to be changed due to the
exchange of presser foot:
1. Remove the rubber plug of the face plate.
2. From this hole, adjust by loosening thc
presser bar clamping screw.
3. After the adjustment, securely t~ghten ttie
set 5crew.
m
If the scrcw (2 of figure is loosened, the slant of the feed dog can be adjusted either to A type
or B type. The maximum protruding amount of the feed dog I \ 0.8 rnm(1132"). Adjust to
this amount by screw ('1' .
Matching the needle and the feed dog
When the needle po~nt has dropped to 3mm
(1/8")bottomthe surface of the throat plate.
adjust the position of the feed dog by the
$crew of figure so that the feed dog sinks
just below the lower surface of the throat
plate.
Adjusting the pressing pressure of the feed
lever
The reversing spring of the feed lever is
strengthened somewhat so that at high speed
sewing, no matter what kind of stitches are
to be formed, the lever returns positively to
the original position.
When the stitching pitch is small or when the
machine is to be run by lowering the r.p.m.,
the pressing pressure of the feed lever can be
lessened by loosening the adjusting nut @ of
the accompanying figure.
L
I
2) On needle bar and needle
Adjusting the height of the needle bar
When an Organ needle (TV x 7) is used, set
the height of the needle bar so that when the
needle bar has reached to lower dead point,
the left side carved line (No.1 mark) matches
with the bottom surface of the needle bar
lower bushing. (See figure)
Also, when the Schmetz needle (UY-128GAS
etc.) IS used, match it so that the right side
carved line comes to the position as men-
tioned above. (At this condition, the distance
bctwecn the needle point and upper surface
of the throat plate becomes 10.0mm(25/64").
3) Matching the needle and the looper
Lvopcr
\
needle
Adjusting the looper avoiding motion
Within the oval movement of the looper,
the dimcnsion of B in the figure can be
adjustcd in the following order.
1 Remove the rubber cap.
2
Rotate the hand wheel with the hand.
3 The heads of the plated adjusting screw(D,
flat top screw, c l G p screw will appear
in that order, so at first, loosen the
2 screws, flat top and clamp screw.
4
If the punched mark of the adjusting
screw (i' is brought to right side, the
dimcnsion of B becomes bigger.
5
Adjustment is made depending on the size
number of the needle but normally it is
adjusted to #1 1 needle.
6 The adjustment should be made so that
the looper goes as near the needle side
as possible and returns. Then. after setting
the pos~tion by tightening the flat top
screw, securely tighten the clamp screw.
Matching the looper
When the needle is at the lowest point, the
looper comes to extreme right position. This
adjustment is made by loosening the screw
of the gear.
Scooping amount of the looper
When the blade point of the looper has reached the center of the needle, the standard
distance between the blade polnt and the upper end of the needle hole is 1.5mm(l/l6"). When
the No. 2 carved Line of the needle bar is matched with the lower edge of the needle bar lower
bushing, adjust so that the blade point of the looper come5 to the center of the needle. The
returning amount of the looper comes to approximately 3.2mrn(1/8") and the relative relation-
ship of the needle hole and the thread hole of the looper becomes as shown In the figure.
Clearance between the looper and the needle
The clearance between the looper and the needle when the looper scoops up the thread should
be as narrow as possible. After ad~usting the needle guard, re-conf~rn~
t h ~ s
condition.
I I
4) On thread spreader
Extreme right end
'Thread
spreader is necessary in case of
reverse sewing and at the same time it is very
important to obtain stable stitches without
slup-stitching in case of normal feed sewing.
The timing of thread spreader against the
needle
As shown in the figure, when the No. 4 mark
of the needle bar appears from the bottom of
the needle bar lower bushng, set the thread
spreader with the thread s~reader cam set
screw, as shown in the figire, so that the
thread spreader comes to extreme nght end.
Position of the thread spreader latch
When the pointed end of the descending needle arrives the level of upper surface of the looper,
adjust the thread spreader to the position shown by the figure.
1, The right and left direction should be such that the inside surface of the thread spreader
thould match with the center of the needle.
2
Adjust so that the front and back dimension A should be 2 mm(5164") with the screw 03.
3 The he~pllt \lluuld be adjusted so that the clearance between the bottom surface of the
thread rpreader uid the upper surface o i the looper to be 0.2 mm(1/100") with the screw (21.
lnslde llne I
~
Threa! spreader
Thread spreader
A
Needle
r-pp Fp
Method of thread spreader
Ci;, When the thread spreader latch returns,
the tip of the thread spreader latch is
positively grasping the looper thread and
one side of the needle thread loop until
the needle point enters the triangle of the
thread.
(3
After the needle point has entered the
triangle, the looper should release the
thread.
Above are the thread spreader adjustments
for both normal and reverse stitches to
form correct st~tches.
5) Needle guard and loop guide
Set sue\; of
needle guard cam
The timing of the needle guard
The timing of the needle guard is determined
by lnatch~ng the first rcrew of the figure
with the flat part of the shaft.
Position of the needle guard
When the looper scoops u ! ~ the necdle thread,
:idjust so that the needle point lightly touches
the needle guard. Set ihr 11c1glir as high as
vossible to about covti the needle thread
loop. Loosen ser (crews
1 ' and \z\ for thls
'tdjustment.
--
A
Looper gdlde
A':
'-
\
Ql
Position of the looper guidc
?'he looper guidc .;l~ould bt: ~ n \ t ; ~ l I ~ d
d i near
the looper as poss~hle \o that it will not
ioucll the looper. Adjuct it so that tht.
dimenhion :)f A \rill be about 0.2 -0.5
rnm
(11100"--1.'64"),
and of 13
ti, be about
0.5 - - 1.0 mnl (1 164"--3/64"3.
Dimension of
A should be adjusted
by
loosening rcre\v I and of B loosen screw 2 .
4. OPERATION AND ADJUSTMENT OF MH-484
1) Sliding tvpe presser foot
6) On looper thread cam
bottom surface of the needle bar lower
bushing, make it so that the wire can be
seen through the hole of the matching hole
of the cam. The timing of the looper thread
cam can be adjusted by loosening the screw B
and after the position is determined tighten
the screw securely.
After all adjustments are completed, verify
the following:
1. Verify that when the looper thread came
off from the protruded end @ of the
looper thread cam, the needle point has
completely entered the triangle of the
looper thread.
2. To especially avoid the puckering, adjust
7) On the position of the take-up thread
the looper cam so that the bottom end of
tension lever
its matching hole is aligned with the lower
side of the wire with a little earlier timing,
when the looper thread will not be drawn
too much and a favourable thread tension
1
will be obtained.
NO. 3 mark
When the needle bar is at the lowest point,
if the needle thread is pulled in by hauling
motion by the take-up thread tension lever,
the needle thread loop becomes big at the
scooping time of the needle thread.
As shown in the figure, when the No. 3
carved line of the needle bar comes t o the
In case of normal fine thread, lower the
I
needle to the lowest dead point.
8) On the frame thread eyelet
The thread tightening changes according to
the positions of the frame thread eyelet.
When the frame thread eyelet is lowered,
the tightening of the looper thread becomes
weaker and if it's raised up, the tightening
becomes stronger.
Adjustin
screw
3
Lock nut
Mli-484 has a sliding type presser foot. Adjust
it as follows:
I . Firmly tightcn thc presser spring requla-
tor.
2. Adjust for a proper sliding motion of the
foot by tightening or loosening the adjust-
ing screw on the presser foot; if the screw
is too tight, thc work will be slipped and if
it is too loose, the work will not be fed qr
pucker.
3. Loosen the presser spring regulator until
the presser foot does not make a noise and
tightcn the lock nut.
2) Stitch length adjustment
--
pi
Set tlic feed regulator dial to a desired stitch
length.
Feed regulator dial
I
(Thc dial IS calibrated in ~ n m )
i
When feed rocker shaft shows a greater mo-
tion like MH-484/S060. the stitch length or.
the dial indicates one half of the actual stitch
length.
1
3) Differential feed adjustment
-
-
lock nut of the regulating lever
the lever angle; pull up the lever
stitch and push it down for stretch
1
s on the differenrial feed dial indi-
~
cate the ratio of the auxiliary feed to the
I
(For example, "0.5" represents 0.9 mm of
!
ed when the main feed is 1.8 mm)
When a greater effect of gather stitch is
required, provide the feed rocker shaft with a
larger motion by increasing the radius of the
arm.
For this purpose, use the figures in parenthe-
sis on the dial.
(For example. "2.5" represents 4.5 mm of the
auxiliary feed when the main feed is 1.8 mm)
However, take care that the feed ratio will
vary according to the difference in the tooth
pitch between the main and differential feed
dogs. Therefore, the indication on the dial
must be used as iust a reference value.
Feed dog height
Differential
Main feed feed dog
do^
I
Throat plate
5) Timing of the feed rocker cam
The standard height of the main feed dog is
0.8 mm (1132") above the throat plate sur-
face. At the highest point, the main feed dog
must be in a front-up (down slope) posture
and the differential feed dog must be in hori-
zontal position as illustrated.
Also adjust the differential feed dog to sink in
the throat plate simultaneously with the main
feed dog.
These adjustment are made by means of the
feed dog setscrews and the feed rocker shaft
Timing of the feed rocker cam (trajectory of
the feed dog) must be changed for stretch or
gather sewing.
Remove the side plate located on the rear of
the machine arm and loosen the feed rocker
cam setscrew.
Adjust the mark line on the feed rocker cam
to the marks "1" shown by the feed driving
cam cover for stretch sewing and "2" for
gather sewing.
After adjusting the feed rocker cam, tighten
its setscrew. All machines have been set for
stretch sewing (Mark "1") before shipment,
excepting MH-484 and MH-484-4-SO60 &
SO61 which have been set for gather sewing
(Mark "2").
After changng the timing of feed rocker shaft
cam, readjust the height of the feed dogs
accordingly.
4. MAINTENANCE OF THE MACHINE
6) Gather sewing attachment
Attachemtns SO60 and SO61 are available for the rnodel M11484.
SO60 (Gather sewing attachment)
SO61 (Intermittent gather sewing attachment)
7---
I
I
With S060, you can gather only the bottom
With SO61 you can intermittently sew gathers
cloth.
as you wish by operating the pedal lever.
Refer to the separate Instruction Book prepared for the SO60, SO61 for the details of adjustment.
To maintain the machine in constant smooth running condition, be sure to do as follows:
1) Give the machine an overall inspection daily and verify its running condition.
* Verify if the oil is circulating smoothly by watching through the oil sight window.
* If a different operator is running the machine daily,, be sure to have him contact an
expert maintenance crew for guidance.
2) Inspect the following parts at least once a week:
* Throat plate, sliding plate and remove the cam cover and by using a brush dust off the
dirt from the groove of the feed dog.
* Tilt the machine toward the opposite side and,
(1) Remove the thread hards stuck to the oil pump netting and remove the rubbish inside
the oil reservoir.
(2) When the oil becomes dirty and blackish. pull out the oil plug and exchange the dirty
oil with new, fresh JUKl Defrix Oil No. 1.
(3) Verify that the oil level is always above the "LOW" mark.
(4)Wipe away the black steel powder sticking to the magnet at the bottom of the oil
reservoir.
No.
MALFUNCTIONS & CORRECTIVE MEASURES
Malfunctions I
Thread
breakage
I
Skip-stitch
Causes
I Corrective Measures
1. Quality of thread is bad.
2. Thread is thick compared
to needle.
3. Thread breakage due to
heat of needle.
4. Thread tension is too
strong.
5. The thread path of
needle, looper, throat
plate, needle guard,
looper guide and all
other thread paths are
bruised.
6. Due to twice passing of
thread.
1. Skip-stitching of needle
thread.
2 stitches collapse
*(This occurs when looper
does not scoop needle
thread)
(3
Use a better quality thread
(2)
Change the needle or
thread to proper size.
@ This occurs on synthetic
thread.
Use silicon oil lubricant.
Lower the [.p.m.
61 Weaken the thread tension.
@ Sharpen with oil whet-
stone or by buffing.
@ Activate the thread take-
up tension lever.
Verify the scooping
amount of looper.
@ Verify the clearance
between the looper and
needle.
@ Verify the timing of the
looper & needle.
C4) Depending on the thread,
activate the thread
take-up tension lever.
Ref.
Page
7
8
6
14
11
11
11
14
1 So. 1 Malfunctions 1
5
Verify the correct
in\tallat~on of the needle
6
Ver~fy the tlmlng of the
needle guard
7
Refer to the passing of
the thread.
1
Corrective Measures
Cause5
2
Looper thread
skip-rt~tzhcs.
c*:*--
!
Ref.
Page
* One stitch collapes
I
Needle .J&=?
- I Looper
* (Tll~t
occurs when the
~ieedlc drop? into the
I
~
triangle of thread.)
1'
Verlfy above @ & 0.
2
Verify the timing of the
looper thread cam
3
Adjust the positlon of
the thread spreader
hook
4
Make the tension of the
looper thread stronger
S
Refer to passing of the
thread
* Inadequate linking of
loop. (Tliis occurs when
the needle thread is too
liiuch on left side.)
Needle
1
Refer to I. 3. of sk~pping
of needle thread
2
Verify the tlming of the
thread spreader and
position of hook of the
looper
l 1
Make the %cooping
(In LJ\C of miked \ynthetic
amount of looper greater
tllrtad I
2
Drop the 5ewlng speed
I
1
3
Use slhcon oil lubrrcant
Heude5 above
1 I
e
o f n
t
i
h
a
I 2
il\e'~ilicon 011 kbricant
I
When the needle thread
tension 19 weak
2
When the bobb~n thread
tenaon I \ ytrong
3
I~~suff~cient
palling out
of looper thread cam
4 The thread IS too thick
against the needle
5
Depending on the posi-
t ~ o n of lntermedlate
thredd gulde
I
1
Tighten the needle thread
tension nut
2
Loosen the looper thredd
tension nut
3 ) Change the thread passing
to looper thread cam
4
Change the needle
Ure needle for synthetic
thread
' 5 Lower the positlon of the
frame thread eyelet.
I
(Please note)
Due to improvements on the mechanism of the machine, the method of operation
and some part of the specification may have to be changed without previous notice.
No.
4
5
6
Malfunctions
Needle
breakage
Puckering
SLipping of
cloth
Causes
6. Position of the thread
take-up thread tension
lever.
7. The throat plate
1. Needle may be curved.
2. Inspect the timing of
the feed dog with the
needle.
3. Inspect the installation
of presser foot.
4. Needle guard
5. When the tension of the
needle thread is too
strong.
6. Thickness of needle.
1. Tens~on of thread is too
strong.
2. Timing of the looper
cam.
3. Processed condition of
thread path.
4. When the pressure given
by the presser foot is too
high.
5. Needle
6 Throat plate
Corrective Measures
(6) Ra~se up the position
of the lever.
e: Use large needle hole
throat plate
d) Change the needle.
@ Is the timing correct ?
(3) See if the hole of presser
foot, hole of throat plate
and loop guide plate are
placed in the center of
needle.
(4;
Verify the timing and
position of needle guard.
Ref.
Page
14
7
10.11
13
@ Make the tension of the
needle thread weaker.
,:6j
Select the correct size
I
7
needle to conform to the
nature of the sewing
cloth and its thickness.
3 Sew with weaker tension.
6
(Especially, lower the
tension of looper thread)
@ Set the timing to a little
14
earlier.
@ Polish the thread path
with lapping agent on
thick thread #8
3) Tighten the adjusting
screw.
1.9 Use a finer needle.
116
Use a throat plate designed
1
for fine materials.
I i; Ratlo of differential feed;
1. Presser foot
2. Pressure of the preser
foot.
Apply 1:0.7 ratio for
gether~ng.
@ Use a sliding type presser
foot.
(zj Reduce the pressure.
