HIGHLEAD GC20618-1DZ Instruction Manual

Parts Catalog
S
HANGHAI BIAOZHUN HAILING SEWING MACHINERY CO.,LTD
.
Instruction Manual
GC20618-1DZ/-2DZ
Direct Drive Heavy Duty Compound Feed
Lockstitch Sewing Machine With Automatic
Thread Trimmer

——CONTENTS ——
1.PRECAUTIONS BEFORE STARTING OPERATION································································1
2.SPECIFICATIONS····························································································································1
3.LUBRICATION ·································································································································2
4.PRECAUTIONS OPERATION ·······································································································2
5.ADJUSTMENT OF NEEDLE BAR STOP POSITION································································2
6.INSTALLING NEEDLE ···················································································································3
7.WINDING BOBBIN THREAD········································································································3
8.SELECTION OF THREAD··············································································································3
9.THREADING·····································································································································4
10. ADJUSTMENT OF STITCH LENGTH AND REVERSE SEWING ·····································4
11. SETTING OF BOBBIN·················································································································4
12. LIFTING THE BOBBIN THREAD ····························································································5
13. BALANCE OF THREAD TENSION ··························································································5
14. ADJUSTMENT OF THREAD TENSION ··················································································5
15. ADJUSTMENT OF PRESSER FOOT PRESSURE··································································6
16. TIMING BETWEEN ROTATING HOOK MOTION AND NEEDLE MOTION ················6
17. ADJUSTMENT OF FEED DOG HEIGHT ················································································7
18. RELATIONSHIP BETWEEN ROTATING HOOK MOTION AND TAKE-UP LEVER
MOTION·················································································································································7
19. RELATIONSHIP BETWEEN HOOK MOTION AND OPENER MOTION························8
20. RELATIONSHIP BETWEEN NEEDLE MOTION AND FEED DOG MOTION················8
21. SAFETY CLUTCH DEVICE ·······································································································9
22. ADJUSTMENT OF THE UPPER FEED····················································································9
23. WALKING FOOT AND PRESSER FOOT VERTICAL STROKE ADJUSTMENT ···········10
24. ADJUSTMENT THE STITCH TOLERANCE··········································································10
25. INSTALLATION OF MOVABLE KNIFE··················································································10
26. ADJUSTMENT OF THREAD TRIMMER CAM ·····································································11
27. ADJUSTMENT OF SCISSORING PRESSURE OF MOVABLE KNIFE AND FIXED
KNIFE ·····················································································································································12
28. SHARPING OF FIXED KNIFE···································································································12
29. ADJUSTMENT FOR CHANGE OF NEEDLE GAUGE PARTS············································12
30. SPECIFICATIONS OF THE OPERATION PANEL································································13
31. VALVE COMPLETE·····················································································································14
PARTS CATALOG························································································································15

— 1 —
1.PRECAUTIONS BEFORE STARTING OPERATION
1) Safety precautions:
（1）When turning the power on, keep your hands and fingers away from the area around/under the needle
and the area around the pulley.
（2）Power must be turned off when the machine is not in use, or when the operator leaves the seat.
（3）Power must be turned off when tilting the machine head, installing or removing the “V” belt,
adjusting the machine, or when replacing.
（4）Avoid placing fingers, hairs, bars etc., near the pulley, “V” belt, bobbin winder pulley, or motor when
the machine is in operation.
（5）Do not insert fingers into the thread take-up cover, under/around the needle, or pulley when the
machine is in operation.
（6）If a belt cover, finger guard, eye guard are installed, do not operate the machine without these safety
devices.
2) Precautions before starting operation:
（1）If the machine’s oil pan has an oil sump, never operate the machine before filling it.
（2）If the machine is lubricated by a drop oiler, never operate the machine before lubricating.
（3）When a new sewing machine is first turned on, verify the rotational direction of the pulley with the
power on. (The pulley should rotate counterclockwise when viewed from the pulley)
（4）Verify the voltage and (single or three) phase with those given on the machine nameplate.
3) Precautions for operating conditions:
（1）Avoid using the machine at abnormally high temperatures（35 or higher℃）or low temperatures（5℃
or lower）.
（2）Avoid using the machine in dusty conditions.
2.SPECIFICATIONS
Model GC20618-1DZ GC20618-2DZ
Max.sewing speed 2500r.p.m
Stitch length 9mm
Presser-foot
stroke
By hand 8mm
By pneumatic 17mm
Alternating movement 2-6mm
Needle size DP×17 21#
Lubrication system Automatic lubrication
Motor 750W sevor motor
Needle gauge 6.4 standard

— 2 —
3.LUBRICATION
1) Oiling(1)
Fill the oil reservoir with
oil up to“H”mark.Oil level
should be periodically
checked. If oil level is
found below“L”level
replenish oil to“H”level.
Use white spindle oil.
2) Oiling(2)
When a new sewing
machine is used for the first
time,or sewing machine left out
of use for considerably long
time is used again,replenish a
suitable amount of oil to the portions indicated by arrow in the below figure.
Adjustment of oiling to rotating hook.
3) Oiling condition
See dripping of oil through the oil sight window to check oiling condition during operation.
4.PRECAUTIONS OPERATION
（1）When the power is turned on or off,keep foot away from the pedal.
（2）It should be noted that the brake may not work when the power is interrupted or power failure occurs
during sewing machine operation.
（3）Since dust in the control box might cause malfunction or control troubles,be sure to keep the control
box cover close during operation.
（4）Do not apply a multimeter to the
control circuit for checking,otherwise
voltage of multimerter might damage
semiconductor components in the circuit.
5.ADJUSTMENT OF NEEDLE
BAR STOP POSITION
When the pedal is kicked down by
heel,the machine stop at“UP”position.If the
marks deviate larger than 3mm,adjust as

— 3 —
follows:
Release the set screw of the magnet positioned piece, adjust the position of magnet positioning piece,
until the machine stops in the needle up position (the marker on the pulley and the reference line of motor
cover to coincide), then tighten the screws.
6.INSTALLING NEEDLE
Note:Before installing the
needle,be sure to turn off the power.
To install the needle,turn the maching
pulley over toward operator(or
counter-clockwise)until the needle bra
moves up to its highest point,put the needle
up into the needle bar(or needle clamp) as deeply as it will go,with the long groove of the needle faced left
side(ro face to face).Tighten the needle set screw securely.
7.WINDING BOBBIN THREAD
Note:When bobbin thread is wound, keep the presser foot
lifted.
Thread tension：Particularly in the case of nylon or polyester
thread,wind the bobbin loosely.
（1）Press the bobbin onto the thread winding shaft.
（2）Pass the thread for winding thread as shown in the figure,
and wind the end of the thread clockwise around the bobbin several
times, then wind the thread on the thread adjuster side counter-clock
wise several times.
（3）Press lever 1 in the direction of the arrow, and start the
sewing machine.
（4）The operation will automatically stop when winding is
completed.
（5）Adjustment of thread winding strength, adjust with the
thread adjuster nut 2.
（6）Adjustment of thread winding amount, adjust by loosening
screw 3 and moving adjustment plate 4:
The thread winding amount will increase when moved in the direction of a.
The thread winding amount will decrease when moved in the direction of b.
8.SELECTION OFTHREAD
It is recommended to use”S”twist thread in the left needle(viewed from front),and “Z”twist thread in the

— 4 —
right needle.When discriminate use “Z”twist thread in both the needles.For bobbin thread,”S”twist thread as
well as “Z”twist thread can be used.
9.THREADING
（1）Pass each thread through thread guide A.
Note: When thin slippery thread (polyester thread) is used pass the thread through thread guide B as
show in figure.
（2）Thread take-up lever to the highest position, pass each thread in the order in figure.
Note: Pressing the tension releasing handlebar , the thread can be pulled out easily.
10.ADJUSTMENT OF STITCH LENGTH AND REVERSE SEWING
Rotate the stitch length adjusting dial to change the stitch length.
When press the feed reversing lever, reverse sewing will take place.Loose the lever, reverse sewing will
disappear
11.SETTING OF BOBBIN
（1）Pulling out 5cm thread tail from the bobbin.

— 5 —
（2）Hold the bobbin so that the bobbin thread is would in right direction and put it into the hook.
12.LIFTING THE BOBBIN THREAD
（1）Put the hook into the bobbin case and press down the latch 1.
The thread end should be left on the bed.
（2）While holding the thread by left hand,rorate the balance wheel one turn by right hand.
By pulling up the needle thread,as shown in the figure,the bobbin thread will be lifted.The combination of
bobbinthreadandneedlethreadshouldbealignedandledbackward.
13.BALANCE OF THREAD TENSION
14.ADJUSTMENT OFTHE BOBBIN THREAD TENSION
There is virtually no need to adjust the bobbin thread tension,
except for special kind of the thread, when slight adjustment will
be necessary.
Turning the adjusting screw clockwise will increase the
tension of bobbin thread, otherwise, the tension of bobbin thread
will decrease.
Needle thread tension should be adjusted in reference to
bobbin thread tension.

— 6 —
To adjust needle thread tension,turn each tension adjusting nut.
Needle thread tension can be also adjusted for special fabric and thread by changing intensity and movable
range of slack thread adjusting spring.
15.ADJUSTMENT OF PRESSER FOOT PRESSURE
Pressure of presser foot is to be adjust in accordance with thickness of materials to be sewn.
First loosen lock nut.For heavy materials,turn the adjust bolt to increase the pressure,while for light
materials,turn the adjust bolt to decrease the pressure as shown in Fig. After the adjustment.Tighten the lock nut.
16.TIMING BETWEEN ROTATING HOOK MOTION AND NEEDLE
MOTION
（1）Set the stitch length to “6”on the stitch length dial.
（2）When the needle is lifted 2.4mm from the lower dead
point,the following positional relationship should be maintained:
a．The lower edge of needle eye should be 2.3mm below the
hook point.
b．The center of the needle the hook point is on a line.
c．Gap between the hook point and the side face of needle
should be 0.05mm.
Note:Positioning of hook point
（1）When the needle is at DOWN position,the smaller gear
should be engaged with the large gear so that the “S”screw of the
latter gear on the reverse side.
（2）Tighten each “S”screw,where is punched for set screw,on
the hook shaft.

— 7 —
（3）Approximate position of hook “C”screw of hook should be found close to the needle when the needle
is at DOWN position.
To finely adjust timing between the needle motion and hook motion,loosen the set screw of large gear and
move the hook saddle in lower shaft axial direction within a rang from 1mm to 2mm.
17.ADJUSTMENT OF FEED DOG HEIGHT
Height of feed dog and pressure of presser foot should be adjusted for individual fabric(s) with the
following cautions:
（1）Fabric will be damaged if the feed dog extends too high,or pressure foot is too large.
（2）Even stitch length cannot be assured if the feed dog is too low or pressure foot is too small.
（3）Feed dog height should be measured at the point where the
needle is at the top position.
For light fabrics: Approx. 0.8mm from throat plate
For usual fabrics: Approx. 1.0mm from throat plate
For heavy fabrics:Apporx.1.2mm from throat plate
Adjustment procedure
a.Lean the machine head backward.
b.Turn the pulley by hand and stop when the feed dog rises to the
maximum height.
c.Loosen the feed bar set screw.
d.Vertically move the feed bar(in the direction indicated by arrow in the figure)to adjust it to adequate
height.
e.After the adjustment,tighten the feed bar set screw.
The feed dog height is factory-adjusted to 1.2mm.
18.RELATIONSHIP BETWEEN ROTATING HOOK MOTION AND
TAKE-UP LEVER MOTION
When the timing belt was removed for its replacement,for example,the relationship between relating hook

— 8 —
motion and take-up lever motion should be adjusted as follows:
（1）Turn the balance wheel and stop when the take-up lever is lifed to its upper dead point.
（2）Lean the machine head backward and make sure the arrow(timing mark)put on the timing belt is in
line with the black line on the boss of lower shaft.
（3）If the timing mark is not in the line with the black,remove the timing belt and install it again to adjust.
19.RELATIONSHIP BETWEEN HOOK MOTION AND OPENER MOTION
（1）Turn the balance wheel by hand and stop when the opener holder is located most remotely from the
throat plate.
（2）Make sure the gap between the bobbin case holder
A and the opener is approximately 0.2mm.
（3）If the gap is too large or small,loosen the opener
holder set screw B and adjust position of the opener.
20.RELATIONSHIP BETWEEN
NEEDLE MOTION AND FEED DOG
MOTION
（1）Set feed length to “0”on the feed setting dial.
（2）Lean the machine head backward.
（3）Loosen the feed lifting rock shaft crank set screw
A and B.
（4）Set the needle at the lowest position.
（5）Adjust the distance between presser rod and
vibration prevention rod to 9mm and temporarily tighten the
feed lifting rock shaft crank set screwsA and B.
（6）If the connection is not at right angle,remove the
back cover,loosen screw C and move the right link to adjust.
（7）After the completion of adjustment,fully tighten
the screw A,B,C.
Note:At the same
time make certain that
needle can enter the feed
dog needle hole at the
center of the hole.

— 9 —
21.SAFETY CLUTCH DEVICE
Safety clutch device is installed to prevent the hook and cog belt from damage in case the thread is caught
into the hook when the machine is loaded abnormally during operation.
1) Function of safety clutch
（1）When the safety clutch acts,the belt pulley will be
unloaded,then the rotation of hook shaft will stop.The arm shaft only
will rotate.Stop the operation of machine.
（2）Clean the thread thoroughly which is caught into the hook.
（3）Turn the pulley bushing by hand,and check whether the
hook shaft rotates lightly and properly,place the clutch device as
follows.
2) How to set the safety clutch
（1）While pressing down the push button on the opposite side of bed by left hand,turn the balance wheel
slowly by right hand away from you as shown in the figure.
（2）The balance wheel will stop by the gear plate,but turn the balance wheel more firmly.
（3）Release the push button.
（4）As shown in the figure,the safety clutch device is set.
3) Force applied to the safety clutch
（1）The force applied to the safety clutch is the smallest when the white mark of the eccentric pin faces
the center of the lower shaft.The force proportionally increase as the white mark faces the outside.
（2）To adjust the force slide the timing belt,loosen the set screw,and turn the eccentric pin.
After the adjustment,make sure to tighten the set screw.
22.ADJUSTMENT OFTHE UPPER FEED
If the uneven feeding occurs according to the fabric.Adjust the long hole of the horizontal feed shaft
crank(right)to adjust the upper feed length.Adjust as follows:
（1）Loosen the bolt.

— 10 —
（2）Move the bolt upward to increase upper feed.
（3）Move the special bolt downward to decrease the
upper feed.The upper feed and the lower feed theoretically
becomes equal at the reference line on the feed connection
crank(right).
Securely tighten the bolt after adjustment
23.WALKING FOOT AND PRESSER
FOOT VERTICAL STROKE
ADJUSTMENT
When fabric with large elasticity is sewn,or when thickness of fabric changes,the vertical stroke(movable
range)of the presser feet should be adjusted as follows:
Adjustment:
（1）Open the cover plate,loosen the special bolt.
（2）The vertical strokes of the presser feet become maximum when the crank rod is moved upward and
set.
（3）The vertical strokes becomes minimum when the nut is moved downward and set.
（4）After the adjustment,fully tighten the special bolt.
The vertical strokes of the presser feet can be adjusted within a range from 6mm to 2mm.
24. ADJUSTMENT THE STITCH TOLERANCE
Screwing the pin that connects the link of back-sewing with the crank of back-sewing(down)can adjust the
tolerance of between the stitches.Screwing the pin in clockwise can increase the stitch of forward
sewing,otherwise,the stitch of back-sewing will be increased.
25.INSTALLATION OF MOVABLE KNIFE
1) Installation of movable knife
（1）Turn the balance wheel and lower the needle bar to the lowest position.
（2）Push the cam follower crank so that the cam roller enters into the thread trimmer cam groove.
（3）Turn the balance wheel until the black mark point on the arm meets the white mark point on the

— 11 —
balance wheel.Set the cam follower crank at this position with a screwdriver temporarily preventing the cam
roller coming out from the cam groove.
（4）Loosen the thread trimmer rocking crank clamp bolts Aand B.
（5）Adjust the movable knife so that the movable knife end slant portion protrudes 0-0.5mm from the
fixed knife,as shown in figure and tighten the bolts A and B.
2) Gap between movable knife and bobbin case holder stopper
（1）Turn the balance wheel by hand until needle reaches the lowest position.
（2）With the needle at the lowest position,depress cam follower crank,turn the balance wheel until the
movable knife reaches the extremity of its stroke.
（3）Manually rotate the inner hook in the direction indicated by arrow in figure and adjust gap between
the movable knife and the inner hook stopper to about 0.5mm(the screws A and B should be loosen for this
adjustment).
26.ADJUSTMENT OFTHREAD TRIMMER CAM
（1）Turn the balance wheel by hand until the needles reach the lowest position.
（2）Maintaining the needle position,depress the cam follower crank and put the cam roller into the groove
of thread trimmer cam.
（3）Turning the balance wheel by hand,adjust the thread trimmer cam so that the movable knife starts
moving when the green mark point on the balance wheel comes in line with the black mark point on the arm.

— 12 —
Note:To adjust,loosen two thread trimmer cam clamp screwsA.
27.ADJUSTMENT OF SCISSORING PRESSURE OF MOVABLE KNIFE
AND FIXED KNIFE
（1）Loosen the fixed knife bracket clamp bolt A.
（2）Turn the vertical position adjusting screw B to adjust meshing pressure and then righter the hexagon
socket head cap screw A.
Note:Since excess pressure cause large torque to the thread
trimming mechanism and trimming failure,adjust it so that thread
can be trimmed with minimum pressure.
（3）Move the movable knife and check that the thread can be
sharply trimmed.
28.SHARPING OF FIXED KNIFE
When the knives dull,the fixed knife should be sharpened as
illustrated in figure.Since it is very difficult to sharpen the movable
knife,replace it with a new one when it dulls.
29.ADJUSTMENT FOR CHANGE OF NEEDLE GAUGE PARTS
（1）Replace the throat plate, feed dog and needle clamp.(Since the throat plate and feed dog are special
parts designed for thread trimming machine, be sure to use those specified by us.)
（2）Lean the machine head backward.
（3）Loosen two connecting link clamp bolts J.

— 13 —
（4）Remove the spring M.
（5）Loosen the hook bracket clamp screws A and B and adjust gap between each needle and hook.
（6）When the needles and hooks have been adjusted, install the spring M.
（7）Contact the rocking cranks C and D to the stopper pins E and F and tighten the connecting link clamp
bolt J.
（8）Turn the balance wheel by band until the needles reach the lowest position.
（9）Loosen the nuts G and H.
（10）Depress the cam follower crank K and adjust the connecting rod L so that the cam roller can
smoothly enter the groove of thread trimmer cam.
（11）Adjustment of the cam groove and the cam roller
a.Push the cam follower crank K so that the cam roller enters into the cam groove.
b.Turn the connecting rod L and adjust the clearance between the cam roller and the cam groove surface N
as small as possible, and tighten the nuts G and H.
c.Push the cam follower crank K again and check that the cam roller enters into the thread trimmer cam
groove smoothly.
30.SPECIFICATIONS OFTHE OPERATION PANEL
The operation panel is integrated with the motor cover.The operation panel LCD module will display the
sewing mode,specifications,bartacking,foot lifting,needle stop position,thread trimmer and low-speed start. Each
key on the operation panel diagram as shown. In addition to the basic operation added four function. (Left :
standard control operation panel Right : integrated control operation panel)
Thread snap
Thread tension
Bartacking
(ON/OFF)
Short thread
Bartacking
(ON/OFF)
Thread tension
Thread snap
Short thread

— 14 —
31.VALVE COMPLETE
This machine is designed with mini valve complete that installed integrately by several valves.For single
needle model is 5 valves,and the two needle model is 4 valves.The function of the valves as shown in Fig.(Left:
standard control system.Right :integrated control system)
A.Short thread B.Thread tension C.Feed reversing D.Presser foot lifting E.Thread tension releasing
(Aonly available with single needle model)

A.ARM BED AND ITS ACCESSORIES
— 15 —— 15 —

Fig.
No. Part No. Name
GC20618-1DZ GC20618-2DZ
Description
A01 H2400B2050 Oil guard 11
A02 H2400B2060 Plate for oil guard 11
A03 HA300B2090 Rubber plug 3 3 Φ8.8
A04 H4715B8001 Rubber plug 4 4 Φ13
A05 H4717B8001 Thread take-up cover 11
A06 HA300B2170 Screw 15 15
A07 HFB1138001 Side cover(left) 11
A08 H4735B8001 Rubber plug 1 1 Φ24
A09 HFD1137101 Bobbin thread winder 11
A10 H3107G0662 Screw 3 3 SM11/64(40)×8
A11 HFB1148001 Side cover(right) 1
A11 HFB0148001 Side cover(right) 1
A12 H6762B8001 Screw 22
A13 H6756B8001 Thread cutter 11
A14 H6738B7101 Thread tension complete 11
A15 H6737B8001 Washer 11
A16 H6736B8001 Thread guide 11
A17 H2000B2010 Rubber plug 1 1 Φ13
A18 H2400B2070 Thread guide 11
A19 H2400B2080 Screw 22
A20 H2000M0090 Oil cup 22
A21 HY91K37101 Solenoid complete 1
A22 H3200B2100 Screw 11
A23 H3212B0066 Thread guide complete 11
A24 H4742E8001 Screw 2
A25 H4751B8001 Tension releasing plate 1
A26 H4912B8001 Screw 22
A27 H4913B8001 Supporter 11
A28 H431040080 Screw 1
A29 H4915B8001 Cover plate 1
A30 H4914B8001 Screw 24
A31 H3200B2170 Screw 1 SM13/64(40)×4
A32 H3200B2160 Slide plate(front) 1
A33 HA300B2190 Needle plate screw 21
A34 H4732B8001 Slide plate(left) 1 1/8"-1/4"
A34 H4812B8001 Slide plate(left) 1
A35 H4917B8001 Needle plate 1
A35 H5014B8001 Needle plate 1
A36 H3200B2120 Needle plate screw 1
A37 H4733B8001 Slide plate(right) 1 1/8"-5/16"
A37 H4813B8001 Slide plate(right) 1
A38 H4911B8001 Cover plate 1
A.ARM BED AND ITS ACCESSORIES
— 16 —

Fig.
No. Part No. Name
GC20618-1DZ GC20618-2DZ
Description
A38 H5015B8001 Cover plate 1
A39 HA100C2190 Screw 1 SM11/64(40)×8
A40 HFB0188001 Electric line holder 1
A41 HFB1118001 Face plate 11
A42 HA106B0675 Thread guide 1
A43 HA106B0676 Screw 1 SM9/64(40)×6
A44 H3000D2160 Screw 1 SM9/64(40)×7
A45 H4726B8001 Thread guide 1
A.ARM BED AND ITS ACCESSORIES
— 17 —

B.THREAD TENSION REGULATOR MECHANISM
— 18 —— 18 —