HIGHLEAD GC1918 -MDZ User manual

Parts Catalog
SHANGHAI BIAOZHUN HAILING SEWING MACHINERY CO., LTD.
GC1918 -MDZ
Direct Drive Semi-Dry Top Variable Feed Lockstitcher
With Auto Thread Trimmer
Instruction Manual

----- CONTENTS -----
1. PRECAUTIONS BEFORE STARTING OPERATION···················································1
1) Safety precautions·············································································································1
2) Precaution before Starting Operation···········································································1
3) Precaution for Operating Conditions············································································1
2. SPECIFICATIONS·················································································································1
3. PREPARETION BEFORE STARTING OPERATION····················································2
Adjustment of needle bar stop position···············································································2
4. PRECAUTIONS FOR STARTING OPERATION····························································2
1) Lubrication ························································································································2
2) Adjustment for amount of oil for hook ·········································································3
3) Periodical cleaning············································································································3
5. HOW TO USE THE MACHINE··························································································4
1) How to attach needle········································································································4
2) Threading···························································································································4
3) Adjusting of stitch length and reverse sewing······························································4
4) Adjustment of the thread guide······················································································5
5) Adjusting the thread tension···························································································5
6) Adjustment of upper thread tension··············································································6
7) Adjustment of lower thread tension···············································································6
8) Adjustment of remaining needle thread length after thread trimming···················6
9) How to wind the lower thread on the bobbin·······························································7
10) Adjustment of feed dog height and inclination····························································7
11) Adjustment of feed timing·······························································································8
12) Adjustment of forward/backward stitch length ··························································8
13) Adjustment of knife engagement····················································································8
14) Adjustment of top feeding·······························································································9
15) Adjustment of sewing shift····························································································10
16) Adjustment of feed timing·····························································································10
17) Presser adjustment of top feed dog··············································································11
18) Position adjustment for presser bar base····································································11
19) Gauge installation···········································································································12
20) Adjustment of upper horizontal forked arm······························································13
21) Adjustment of front and back positions for presser foot··········································13

22) Adjustment of clearance between top feed dog and presser foot····························13
23) Adjustment of vertical motion for top feed dog·························································14
24) Adjustment of top feed arm and top feed lever ·························································15
25) Intermittent ruffling unit use························································································16
PARTS CATALOG
A. Arm bed & Its accessories·····························································································17
B. Needle bar and thread take-up mechanism································································20
C. Feeding and feed lifting mechanism ············································································23
D. Stitch regulator mechanism···························································································26
E. Top feed rock shaft mechanism····················································································29
F. Presser foot mechanism ·································································································32
G. Top feed mechanism·······································································································35
H. Presser foot mechanism ·································································································38
I. Thread trimmer mechanism·························································································40
J. Touch back mechanism··································································································43
K. Motor mechanism···········································································································45
L. Oil lubrication mechanism····························································································47
M. Accessories ·······················································································································49

—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 used,.
(3) The power must be turned off before tilting the machine head, installing or adjusting the machine, or
when replacing.
(4) Avoid placing fingers, hairs bars etc. nears the pulley, bobbin winder pulley, when the machine is
operation. Injury could result.
(5) Do not insert fingers into the thread take-up cover, under/round the needle, or pulley when the
machine is in operation.
(6) If a mini motor cover, finger guard, and/or eye guard are installed, do not operate the machine
without these safety devices.
2) Precaution 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) Precaution for Operating Conditions
(1) Avoid using the machine at abnormally high temperature (35℃or higher) or low temperatures (5℃
or lower). Otherwise, machine failure may result.
(2) Avoid using the machine in dusty conditions.
2. SPECIFICATIONS
Material weight GC1918-MDZ
Max. speed 4000rpm
Stitch length 0 to 4mm
Needle bar stroke 31.8mm
Presser foot
clearance
Hand Lifter 4 mm
Knee lifter 11 mm
Needle type DB×1 #14
Hook (for thread trimming) Full rotation automatic lubrication (standard)
Touch back yes
Thread trimming method Left knife rotating, right knife fixed engagement type
Working dimensions 300×135 mm

—2—
3. PREPARETION BEFORE START TO OPERATE
Adjustment of needle bar stop position
Adjust of "UP" position
When the pedal is kicked down by heel, the machine
stops at "UP" position. If the marks deviate larger than
3mm adjust as follows.
(1) Loosen the screw1 and 2.
(2) Run the machine and stop at "UP" position. Then turn
the magnet base counter clockwise until the
screws 4 on the upside and then tight the screws.
(3) When the 1st mark of pulley is align with the timing
mark arm, tighten the screw 2, then tight the screw 1.
4. PRECAUTIONS FOR STARTING TO OPERATE
1) Lubrication
Before starting sewing machine operation,
fill oil for hook lubrication into the oil tank.
(1) Remove the rubber plug from the oil port,
and fill the oil from the oil port.
(2) Fill in oil until the tip of the oil level indicator
matches the line in the oil check window.
(3) When done filling the oil, set the rubber plug
into the oil port.
(4) If the tip of the oil level indicator drops below
the line in he oil check window during operation,
replenish the oil.

—3—
(5) Oiling 15 to 20 drops once a week.
2) Adjustment of the amount of oil for
hook
turn the oil level adjustment screw, and adjust
amount of oil for hook..
3) Periodical cleaning
a. Machine
(1) Remove the throat plate and clean the feed dog.
(2) Assembling is to be made by screwing in the
screw by 2 to 3rotations by hand at first, then
tightening them evenly by use of a long size
screw driver.
3) Lay down the machine head and clean the hook
and inner bobbin case.
b. Maintenance of motor
Remove dust from the motor filter every one or
two month. (If operation is continued with the
filter clogged with lint or dust, the motor might
overheat.)
c. Control box
Remove dust from the connector (If the
connector covered with dust, machine might
misoperation.)

—4—
5. HOW TO USE THE MACHINE
1) How to attach needle
Note: Before making the following adjustment, be sure to
switch off the power source.
Insert the needle up to the bottom of needle clamp and
tighten the screw keeping the long groove side of needle
forward the left．
Note: if snapping of thread occurs during back Sewing with
polyester threads，it may be avoided by fitting the
needle with the long groove Shifted to the front side．
Use DB×1 or DA×1 needle.According to fabric & thread ,please choose the size of needle as follows.
Size of Needle No. of thread Fabric
#9 #100 to #80 Extra thin fabric such as de Chin, Georgette, Organdy.etc
#11 #80 to #60 Thin fabric such as Silk, Calico, Poplin. etc.
#14 #60 to #50 General fabrics such as Cotton,Wooden fabric ,etc.
#16 #50 to #30 Thick Cablico,Thick wooden fabric, Water proof cloth, thin leather,ect.
#18 #40 to #20 Thick fabric such as Suiting and Coat material, thin Pouches, Denim , ect.
2) Threading
Raise the thread take-up lever to its highest position and thread the upper thread in the following order.
3) Adjusting of stitch length and reverse
lever
(1) Rotate the drop feed dial while depressing the
reverse lever and then, pressing the push lever,
when making the stitch length shorter.
(2) If the reverse lever is depressed, reverse sewing
(backward sewing) will take place.

—5—
(3)Touchback switch
a. With the push-button (touchback switch) pressed
lightly during sewing, reverse sewing can be done.
Reverse sewing will take place while the push-button is
pressed.
When the push-button is released, reverse sewing turns
into forward sewing.
b. When the push-button is turned 180 degrees in the
direction of the arrow, the switch will be locked, and
backward sewing will not take place even if the button
is pressed.
4) Adjusting of the thread guide
1 2 3
Thread guide position
Left Middle Light
Materials Heavy Medium Light
Thread(Ref.)
Polyester
Cotton
Vinylon #30 or more
Polyester #50 to #60
Polyester
#50 to #60
Cotton
Vinylon
#50 to #80
Refer to the table above, and adjust according to the stitching conditions, the material and thread
5) Adjusting of thread tension

—6—
6) Adjusting of upper thread tension
(1) Upper thread tension can be adjusted by thread
tension nut.
(2) Upper thread is to be adjusted according to the
lower thread tension.
(3) For special fabric sewing with special thread, the
desired tension can be obtained by adjusting the
strength and operating range of thread take-up
spring.
7) Adjusting of lower thread tension
(1) Lower thread tension can be adjusted by screw (A).
(2) In the case of cotton thread #60, the thread
tension can be checked as the following. Hold the end
of pulled out thread and if the bobbin case fall slowly,
the tension is proper.
8) Adjustment of remaining needle thread
length after thread trimming
(1) Turn the pretension nut ①and adjust.
(2) When turned clockwise, the length of thread left
in the needle will be short.
When turned counterclockwise, the length of the
thread left in the needle will be long.

—7—
9) How to wind the lower thread on the
bobbin
(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 ①in 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 ③and moving the
adjustment plate ④
a. The thread winding amount will decrease when
moved in the direction of a.
b. The thread winding amount will increase when
moved in the direction of b.
10) Adjustment of feed dog height and inclination
(1) As a standard, the eccentric shaft ①mark on the left of the horizontal feed arm is set to the direct
left side, and the feed dog height is set to 0.8mm (maximum) as shown in the figure.
(2) To adjust the feed dog height and inclination,
loosen the screw ③, and turn the eccentric
shaft ④, loosen the screw ②at the left of the
horizontal feed arm, and turn the eccentric shaft
①.
(3) When the eccentric shafts are set to "DOWN"
position, puckering may be avoided and free
loop is less likely to occur.
(4) When the eccentric shafts are set to "UP"
position, misalignment of fabrics is less likely to
occur and yarn severance may be avoided.

—8—
11) Adjustment of feed timing
(1) Adjust by changing the position of the vertical feed
eccentric ring.
(2) As a standard, the vertical feed timing Is set to when
the screw ①on the bearing bushing is linear with
screw ②on the vertical feed eccentric ring.
(3) When the eccentric ring is moved in the direction of
a, the vertical feed dog will rise earlier.
(4) When the eccentric ring is moved in the direction of
b, the vertical feed dog will rise later.
12) Adjustment of forward/backward stitch
length
(1) Loosen screw ①on the right of the adjustment arm.
(2) Turn the eccentric shaft ②and adjust.
(3) The forward stitch length will increase and the
backward length will decrease when the eccentric
shaft ②is turned counterclockwise.
(4) The forward stitch length will decrease and the
backward length will increase when the eccentric
shaft ②is turned clockwise.
13) Adjustment of knife engagement
a. Position of fixed knife
(1) As a standard, the dimension between the fixed
knife's end and the needle center is 2.5mm.
(2) The standard relation of the knife (left) and fixed
knife is shown in the figure. As a standard,
Dimension A is 0.3mm.
(3) When Dimension A is too large, the three piece of
threads will be cut, and can cause the needle thread to
come out from needle after trimming. If too small,
the thread may not be trimmed correctly.

—9—
(4) Adjust by adjusting the installation of the fixed knife.
b. Knife engagement amount
(1) When the sewing machine is rotated while the
solenoid is activated, the knife (left) will be rotated
by the thread trimming cam.
As a standard, the knife engagement amount should
be 1.5 to 2.0mm when the knife (left) moves the most.
(2) Adjustbyadjustingtheinstallationofthedrivearm.
c. Adjustment of knife engagement pressure
(1) As a standard, the knife (left) and fixed knife should
start contacting at the position shown in the figure.
(2) To adjust the engagement pressure, loosen the lock
nut ②and then adjust the adjustment screw ①.
14) Adjustment of top feeding
(1) The top feeding amount will increase when turning the top feeding dial clockwise ((+) side), and
decrease when turning counterclockwise ((-) side). It may be possible to make the magnitude of the top
feeding amount the standard aim, in accordance with the position of the top feeding indicator o the top
feeding scale plate.
(2) The intermittent ruffling stopper dial, regulates the maximum top feeding amount, when using the
intermittent ruffling sewing unit (option).
(3) Set the intermittent ruffling stopper dial to MAX.(8 mm) in case of no intermittent ruffling sewing unit
(option) used.
(4) Set the intermittent ruffling stopper dial to MAX. as follows:

—10 —
a. Set the top feeding dial to 3 or more.
b. Turn the intermittent ruffling stopper dial clockwise fully.
c. The position, such as the dial strikes and does not turns any more, is “MAX.” position. (The scale "8"
comes just above.)
d. Reset the top feeding dial to the desired scale.
15) Adjustment of sewing shift
(1) In case of the lower cloth longer at the sewing end:
Adjust the sewing shift by turning the top feeding dial
counterclockwise ((-) side).
(2) In case of the upper cloth longer at the sewing end:
Adjust the sewing shift by turning he top feeding dial
clockwise ((+) side).
(3) Ruffling sewing
Turn the top feeding dial clockwise ((+) side) with
using pusher type gauge and separator.
The ruffling sewing is possible by increasing the
top feeding amount.
16) Adjustment of feed timing
(1) When the thread take-up, set the second screw of
camup.
(2) When regulation, open rubber plug in the back, adjust
The installed position of the cam.

—11 —
17) Presser adjustment of top feed dog
(1) Press down the top feed adjusting knob. The presser to
the top feed dog will become stronger when turning .
the knob clockwise, and weaker when turning
counter-clockwise. (Rotate the top feed presser
adjusting knob in such condition as engaged firmly,
after depressing downward.)
(2) The height A is approx. 51 mm as standard, when the
top feed adjusting knob is depressed downward, with
the presser foot bottom contacted to the throat plate
after dropping the presser foot down.
(3) The stronger the top feed dog pressure becomes, the
better the top feed efficiency will become. The weaker
the top feed dog pressure becomes, the worse the top
feed efficiency will become.
(4) It should be avoid to make the top feed dog pressure
stronger too much, because the cloth may result in slip or damage due to the presser foot lifted up by the
top feed dog.
18) Position adjustment for presser bar base
(1) Set the feed dog position lower then the
needle plate surface.
(2) Raise the presser foot lifter.
(3) Insert the 4 mm block chip between the
presser foot and the needle plate.
(4) Fasten the screw A of the presser bar base
so that the bottom of the presser foot touch
the 4mm block chip.

—12 —
(5) When fasten the screw A of the presser bar base, adjust
the clearance B between the feed rocker bar bushing and
the presser bar base evenly and set the presser foot in
proper condition that the needle position is on the center
line of the slot of the presser foot.
(6) Make sure the presser bar base can be moved up and
down smoothly by removing the presser spring. If it can
not move smoothly, adjust again with same procedures
mentioned above.
(7) Set back the presser spring.
19) Gauge installation
(1) Gauge removal
a. Remove the needle by loosening the needle set screw A.
b. Remove the presser foot by loosening the presser foot set screw B. (It is very easy to remove the presser
foot by raising the Top feed dog up.)
c. Remove the Top feed dog by removing the
Top fed dog sescrew C.
d. Remove the throat plate by removing the
throat plate set screw D. (It is very easy to
loosen or tighten the throat plate set screw
D by using the driver plate included in the
accessories.)
e. Remove the Drop feed dog by removing the
Drop feed dog retaining screw E.
(2) Gauge installation
a. The installation should be conducted in the
reverse order of
the gauge removal.
b. Confirm the height of the Drop feed dog
after installation.
.

—13 —
20) Adjustment of upper horizontal forked arm
(1) Set the drop feed dial to "3",
and the intermittent ruffling
stopper dial and the Top
feeding dial to MAX. (8),
respectively.
(2) The clearance A between the
upper horizontal forked arm
and the arm (the side cover
attaching surface) is to be
adjusted to approx. 5.5 mm,
when the lower end of the
upper horizontal forked arm
comes nearest to the left side.
(3) The adjustment should be
conducted at the setscrew C
by loosening the screw B.
(4) Tighten the screw B and
screw C securely after adjusting.
21) Adjustment of front back positions for presser foot
(1) the attaching hole A is a elongated hole.
(2) The distance B between the presser foot long
groove and the needle drop center is to be
adjusted to approx. 1 mm , when installing
the presser foot by using the screw C.
22) Adjustment of clearance between top feed dog and presser foot
(1) Set the top feeding amount to MAX.(8 mm) position.
(2) Rotate the pulley, until the clearance A (the clearance between the top feed dog and the presser foot,
when the top feed dog comes nearest to the left side, in case of the pusher type gauge) or the clearance
B (the clearance between the top feed dog and the presser foot, when the top feed dog comes nearest
to the right side, in case of the puller type gauge) will become the minimum.

—14 —
(3) Remove the side cover from the back side of the arm.
(4) Loosen the setscrew C on the upper horizontal arm.
(5) Move the top feed dog, so that the dimension A (in
case of the pusher type gauge) or the dimension B
(in case of the puller type gauge) becomes 1.0 mm.
(6) Tighten the setscrew C on the upper horizontal arm.
Caution: It is recommended to tighten the setscrew C,
while pushing the upper horizontal arm lightly
to the direction of the arrow mark E so that no
play occurs on the upper rocker shaft D to in
the direction of the thrust.
23) Adjustment of vertical motion for top feed dog

—15 —
(1) Remove the side cover from the back .side of the arm.
(2) Set the horizontal feeding amount of the top feed dog
to approx. 3 mm.
(3) Set the top feed dog at the most highest position by
turning the pulley.
(4) Loosen the setscrew A on the top feed vertical arm.
(2) Adjust the rising dimension D with the roller B on the
top feed vertical arm pushing the bell crank C, so that
it becomes the dimensions as follows:
In case of the pusher type
top feed dog 3.0 mm
Incase of the puller type
top feed dog 1.6 mm
(6) Tighten the setscrew A securely after adjusting.
24) Adjustment of top feed arm and top feed lever
(1) Set the drop feed dial A to "0".
(2) Adjust the dimension B to 6.5 mm or more by turning the top feed dial.
(3) Loosen the setscrew C on the top feed arm.
(4) Adjust the link E up and down so that the shouldered pin D will be arranged sideways.
(5) Align the top feed indicator F on the top feed lever with the zero point on the top feed scale plate.
(6) Tighten the setscrew C on the top feed arm securely.

—16 —
25) Intermittent ruffling unit operating method
(1) Operating method
a. When it comes to the position to make the ruffle sewing, the ruffling sewing can be done by operating
Pneumatic Button 1.
b. As the pedal is reverted, it returns to the ordinary sewing.
(2) Adjustment of ruffling amount
a. Press Pneumatic Button 1 and confirm the top
feeding indicator 4 moves.
b. The value indicated with the indicator 4 when
Pneumatic Button 1 is not operated, means the
upper feed pitch under the ordinary sewing state.
c. The value indicated with the indicator 4 when the
Pneumatic Button 1 is fully pressed, means the max.
upper feed pitch at the intermittent ruffling sewing.
d. Max. upper feed pitch at the intermittent ruffling
sewing is adjusted by turning the intermittent
ruffling stopper dial 2. The pitch is extended with
a right turn while it is reduced with a left turn.
e. To confirm the max. upper feed pitch at the intermittent ruffling sewing, press Pneumatic Button 1,will
watching the value of the indicator 4 pointed on the scale plate 3.

A.ARM BED AND IT'S ACCESSORIES
─ 17 ─