HIGHLEAD GC24698-25L User manual

Parts Catalog
SHANGHAI HUIGONG NO.3 SEWING MACHINE FACTORY
GC24698-25L/-25R
Long Arm Post Bed Compound Feed Split
Lockstitch Sewing Machine
Instruction Manual

----- CONTENTS -----
Preparation for operation···············································································································1
1. Safety precautions ·································································································································1
2. Precaution before Starting Operation ·································································································1
3. Precaution for Operating Conditions ··································································································1
Cautions on use·········································································································································1
1. Lubrication ············································································································································1
2. Cautions on operation ··························································································································2
Operation ·····················································································································································2
1. How to attach needle ·····························································································································2
2. How to wind the lower thread ··············································································································2
3. Selection of Thread ····························································································································· 2
4. How to route the upper thread ············································································································3
5. Adjustment of stitch length and reverse sewing ·················································································3
6. Balance of thread tension ·····················································································································3
7. Upper thread tension ····························································································································4
8. Adjustment of pressure of presser foot ·······························································································4
9. Timing between rotating hook motion and needle motion ································································4
10. Adjustment of Feed dog height ············································································································4
11. Walking foot and presser foot vertical stroke adjustment ································································5
12. Safety clutch device ·······························································································································5
Specifications ················································································································································6
PARTS LIST ·················································································································································7
A. ARM BED MECHANISM ···················································································································7
B. THREAD TENSION REGULATOR MECHANISM ·······································································9
C. ARM SHAFT MECHANISM ············································································································11
D. PRESSER FOOT MECHANISM ·····································································································13
E. THRED TAKE-UP LEVER & NEEDLE BAR MECHANISM ·····················································16
F. STICH REGULATOR MECHANISM ·····························································································19
G. LOWER AND FEEDING SHAFT MECHANISM ··········································································21
H. FEED BAR MECHANISM ················································································································24
I. HOOK SADDLE MECHANISM ···································································································· 26
J. OIL LUBRICATION MECHANISM ·······························································································28
K. ACCESSORIES ··································································································································30
L. PNEUMATIC CONTROL UNIT ······································································································33

Preparation for 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) Never operate the machine before filling the machine’s oil pan.
2) When a new sewing machine is first turned on, verify the rotational direction of the pulley with the
power on.
3) Verify the voltage and phase (single or three) 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.
Cautions on use：
1. Lubrication (Fig.1, Fig.2)
When a new sewing machine is
used for the first time, or sewing
machine left out of use for a long time is
used again, replenish a suitable amount
of oil to the portions indicated by arrow
in the fig.
Note: Filling the oil to the fount
timely (Fig.3). Use white spindle oil.
—1 —

2. Cautions on operation
1) When the power is turned on or off, keep foot away from the pedal.
2) It should be noted that the brake might not work when the power is interrupted or power failure
occurs during sewing machine operation.
3) Periodically clean the machine.
Operation
1. How to attach needle (Fig.4):
Note: Before attach needle, be sure to turn off the power.
Loosen the needle clamping screw；Hold the needles so that the two
needles side with the long grooved (faces each other), and insert it as deeply as
it will go into the needle clamping holes, tighten screws.
2. How to wind the lower thread (Fig.5):
Strength of winding：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 A 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 B.
(6)Adjustment of thread winding amount, Adjust by loosening screw C and moving the adjustment plate D
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.
3. Selection of Thread（Fig.6）:
It is recommended to use “S” twist thread in the left needle (Viewed from front), and “Z” twist thread in the
right needle.
When discriminate use of needle thread is impossible, use “Z” twist thread in the needle. For bobbin thread,
“S” twist thread as well as “Z” twist thread can be used.
—2 —

4. How to route the upper thread (Fig.7, Fig.8):
1) Pass each upper thread through thread guideA
Note: when thin slippery thread (polyester thread for example) is used pass the thread through thread
guide B as show in Fig.7
2) With the take-up lever located at the upper most position, pass each thread in the order in Fig.8.
Note: Pressing the upper thread loosening button, the upper
thread can be pulled out easily.
5. Adjustment of stitch length and reverse sewing (Fig.9 Fig.10):
1) Rotate the stitch length adjusting dial to change the stitch length
2) If the reverse lever/push-button is depressed, reverse sewing will take place.
6. Balance of thread tension (Fig.11):
—3 —

7、Upper thread tension (Fig.12):
1) The upper thread can be adjusted based on the lower thread tension.
2) Adjustment can be done by rotating the thread tension nut.
—4 —
8. Adjustment of pressure of presser foot (Fig.13):
1) Pressure should be adjusted according to the material
to be sewn.
2) Turning the pressure adjusting screw to adjust the
pressure of presser foot
9. Timing between rotating hook motion
and needle motion (Fig.14):
1) Set stitch length to “6”;
2) When needle is lifted 2.4mm from the lower dead
point, the following position relationship should be
maintained:
·The upper edge of needle eye should be 2.3mm below
the hook point
·The hook point should be located at the center of
needle axis.
·Gap between the hook point and the side face of needle should
be 0.05 mm
10. Adjustment of Feed dog height (Fig.15):
Height of feed dog should be adjusted for individual fabrics with the
following cautions:
1) Fabric will be damaged if the feed dog extends too high or
pressure of presser foot is too large
2) Even stitch length cannot be assured if the feed dog is too low
or pressure of presser foot is too small

3) Feed dog height should be measured at the point where the needle
is at the top position.
For light fabric: Approx 0.8mm
For usual fabric: Approx 1.0mm
For heavy fabric: Approx 1.2mm
Adjustment procedure:
1) Lay down the machine bed toward the other side;
2) Turn the balance wheel by hand stop when the feed dog is raise to its highest position from the surface of
needle place;
3) Loosen the Screw and adjust the height of the feed dog;
4) After adjusted, tighten the screw.
The feed dog height is factory-adjusted to 1.2mm
11. Walking foot and presser foot vertical
stroke adjustment (Fig.16):
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:
1) Loosen the special bolt;
2) The vertical strokes of presser feet become minimum
when the crank rod is moved downward and set;
3) The vertical strokes of presser feet become minimum
when the crank rod is moved upward and set;
4) After the adjustment, tighten the special nut.
The vertical strokes of presser feet can be adjusted within a range from 2mm to 6mm.
12. Safety clutch device (Fig.17, Fig.18)
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 operation.
1) Function of safety clutch:
A. When the safety clutch acts, the cog belt pulley will be unloaded.
Then the rotation of hook shaft will stop. The arm shaft only will
rotate. Stop the operation of machine.
B. Clean the thread thoroughly which is caught into the hook.
C. Turn the cog belt hub 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 (Fig.18)
A. 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;
—5 —
B. The balance wheel will stop by the gear plate, but turn the
balance wheel more firmly;

—6 —
C. Release the push button, the safety clutch device is set.
3) Force applied to the safety clutch (Fig.18)
A. The force applied to the safety clutch is the smallest when the mark of eccentric pin faces the center of
the lower shaft. The force proportionally increases as the mark faces the outside;
B. To adjust the force slide the timing belt, loosen the set screw, and turn the eccentric pin;
C. After the adjustment, tighten the set screw.
Specifications:
Model
Spec GC24698-25R/GC24698-25L
Material weight Medium Heavy material
Max. sewing speed 1200rpm
Stitch length 0-7mm
Needle bar stroke 33.4mm
By hand 8mmPresser
foot stroke By knee 16mm
Alternating movement 2-6mm
Stitch-length adjusting Dial type
Alternating movement Automatic
Needle DP×17（22#--24#）
Motor Servo Motor 550W

A. ARM BED MECHANISM
— 7 —

Fig.
No. Part No. Description
GC24698-25R
GC24698-25L
Remarks
A01 HA300B2090 Rubber plug 22
A02 HA300B2170 Screw 15 15 SM11/64（40）×9
A03 H4716B8001 Oil guide plate 11
A04 H4717B8001 Thread take-up cover 11
A05 H4715B8001 Rubber plug 11
A06 H4718B8001 Arm side cover (left) 11
A07 H2000B2010 Rubber plug 11
A08 H7117B8001 Arm side cover 22
A09 HA700B2060 Screw 2 2 SM11/64（40）×8
A10 H2400B2100 Thread guide 11
A11 HA307B0673 Rubber plug 11
A12 H4715H8001 Push button 11
A13 H4714H8001 Spring 11
A14 H007013050 E-type ring 11
A15 H2000M0090 Cap 33
A16 H3200B2100 Screw 11
SM9/64（40）×6.5
A17 H3212B0066 Thread guide 11
A18 H3000D2160 Screw 11
SM9/64（40）×4.5
A19 H4726B8001 Thread guide 11
A20 H4727B8001 Face plate 11
A21 H2400B2080 Screw 22
SM3/16（28）×12.1
A22 H2400B2070 Thread guide 11
A23 H4730B8001 Guide mounting plate 11
A24 H2400B2060 Spacer 11
A25 H3200B2060 Oil guide plate 11
A26 H7007D7101 Bobbin winder 11
A27 H7014D7101 Down-lead complete 11
A. ARM BED MECHANISM
—8 —

B. THREAD TENSION REGULATOR MECHANISM
— 9 —

Fig.
No. Part No. Description
GC24698-25R
GC24698-25L
Remarks
B01 H2504C6510 Screw 2 2 9/64（40）×3
B02 H3221B3142 Tension releasing plate 11
B03 H3221B6812 Tension releasing spring 11
B04 H4705C8001 Screw 11
B05 H4706C8001 Lever 11
B06 HA7311C306 Screw 1 1 9/64（40）×7
B07 H4707C8001 Mounting plate 11
B08 H007013050 E-type ring 1 1 GB/T896 5
B09 H3221B6820 Mounting plate 11
B10 HA300C2030 Screw 2 2 11/64（40）×8
B11 H3221B6810 Nut 22
B12 H4708C8001 Spring 11
B13 H4709C8001 Push button 11
B14 H3221B0683 Thread tension stud 1 1 11/64（40）×14
B15 HA112B0693 Thread tension disc 22
B16 H3221B0684 Spring 11
B17 HA710B0671 Thumb nut 11
B18 H3221B0682 Pin 22
B20 HA106B0676 Screw 1 1 9/64（40）×6
B19 H3306B0661 Thread guide 11
B21 HA310B0702 Tension releasing disc 11
B22 H4710C8001 Spring 11
B23 HA115B7010 Thumb nut revolution stopper 11
B24 HA310B0701 Thumb nut 11
B25 HA310B0705 Thread tension disc 22
B26 H3221B6817 Pin 11
B27 H3221B0686 Thread tension stud 1 1 1/4（40）×23
B28 H32481B721 Thumb nut 11
B29 H32481B621 Take-up spring guide 11
B30 H32481BE21 Plate complete 11
B31 H4713C8001 Thread take-up spring 11
B32 H32481BD21 Plate complete 11
B33 H4804C8001 Thread tension stud 1 1 9/64（40）×2.9
B34 H4805C8001 Thread tension stud 1 1 1/4（40）×14.5
B35 H3230K0751 Screw 1 1 11/64（40）×10
B36 H3221B6817 Pin 11
B37 H4769E8001 Pin 11
B38 H3200B2100 Screw 1 1 9/64（40）×6.5
B39 H3221B6819 Stopper 11
B. THREAD TENSION REGULATOR MECHANISM
—10 —

C. UPPER SHAFT MECHANISM
— 11 —

Fig.
No. Part No. Description
GC24698-25R
GC24698-25L
Remarks
C01 HA307C0662 Set screw 11
SM1/4（40）×6
C02 H33111C104 Crank 11
C03 HA105D0662 Set screw 11
SM1/4（40）×4
C04 HA100C2060 Screw 11
SM9/32（28）×13
C05 HA100C2070 Screw 11
SM9/32（28）×14
C06 H4708D8001 Set screw 1 1 SM1/4(24)×13
C07 H32111B104 Felt 11
C08 H32111B204 Arm shaft bushing (left) 11
C09 H7004D8001 Arm shaft 11
C10 H3205C0661 Spring flange 33
C11 HA113F0684 Screw 33
SM15/64（28）×8.5
C12 H3205C1021 Pulley 11
C13 HA100F2130 Screw 11
SM15/64（28）×14.5
C18 H7104D8001 Cog belt 11
C19 HA104F0654 Screw 11
SM15/64（28）×10
C20 H4713D8001 Link 11
C21 H4714D8001 Pin 11
C22 H4716D8001 Spring 11
C23 H007013025 E-type ring 11
C24 H4717D8001 Link 11
C25 H4718D8001 Pin 11
C26 H4719D8001 Link 11
C27 H4715D8001 Pin 11
C28 H4720D8001 Bushing 11
C29 H4721D8001 Screw 11
SM15/64(28)×10.5
C30 H4722D8001 Pulley 11
C31 H4723D8001 Screw 22
SM15/64(28)×4.5
C32 H007009300 Retaining ring C-type 1 1 GB/T894.1 30
C33 HA700R0060 Washer 11
C34 HA700R0050 Support spring 11
C35 HA700R0040 Spacer B 11
C36 H4928L8001 Speed command disk F20 (up) 11
C37 HA700R0030 Spacer A 22
C38 H4930L8001 Speed command disk F11 (down) 11
C39 HA110D0672 Screw 22
SM15/64（28）×12
C40 H4931L8001 Pulley (complete) 11
C41 HA703R0067 Washer 11
C42 HA703R0065 Detector bracket (complete) 11
B39 H3221B6819 Stopper 11
C. UPPER SHAFT MECHANISM
—12 —

D. PRESSER FOOT MECHANISM
— 13 —

Fig.
No. Part No. Description
GC24698-25R
GC24698-25L
Remarks
D01 H4705E8001 Feed lifting rock shaft 11
D02 H4707E8001 Bushing 22
D03 H0030580608 Nut 1 1 (M6×0.75)
D04 H4706E8001 Set screw 2 2 SM1/4（24)×7
D05 H4709E8001 Crank 11
D06 H3115F0671 Screw 11
SM1/4（28）×16
D07 H2013J0065 Washer 11
D08 H2014J0066 Connecting rod 11
D09 H2000J2100 Screw 1 1 M6(0.75)×24
D10 H4713E8001 Oil wick 11
D11 H20111C106 Holder 11
D12 H007009250 C-type ring 11
D13 H4714E8001 Eccentric 11
D14 HA307C0662 Screw 22
SM1/4（40）×6
D21 H3100G2170 Screw 1 1 SM1/4（24）×17
D22 H4730E8001 Lever spring 11
D23 H4729E8001 Screw 11
SM15/64（28）×79
D24 H4727E8001 Twist spring 11
D25 H4728E8001 Knee lifting lever 11
D26 H3100G2130 Screw 1 1 SM1/4（24）×7
D27 H4726E8001 Nut 11
D28 H4725E8001 Screw 11
SM1/4（24）×19
D29 HA111G0683 Screw 2 2 SM11/64(40)×12
D30 H4723E8001 Guide 11
D31 H4754E8001 Presser bar 11
D32 H4744E8001 Bushing 11
D33 H3200E2020 Screw 1 1 SM1/8(44)×9
D34 H4746E8001 Spring bracket 11
D35 H4768E8001 Thread releasing plate 11
D36 H2404I0034 Screw 11
SM9/64（40）×8.5
D37 H4748E8001 Lift lever 11
D38 H4767E8001 Spring 11
D39 H4752E8001 Bracket 11
D40 H4749E8001 Screw 1 1 SM11/64（40）×8.5
D41 H0207E8001 Bell crank 11
D42 H2004J0655 Screw 11
SM3/16（28）×10
D43 H4717E8001 Roller 11
D44 H4718E8001 Screw 11
SM11/64(32)×6
D45 H2004J0662 Screw 1 1 SM1/4(40)×5
D46 H4719E8001 Link 11
D47 HA100E2150 Screw 22
SM11/64（40）×10
D48 H4722E8001 Washer 22
D49 H4721E8001 Bell crank guide 11
D. PRESSER FOOT MECHANISM
—14 —

Fig.
No. Part No. Description
GC24698-25R
GC24698-25L
Remarks
D50 H4753E8001 Screw 1 1 SM11/64（40）×17.5
D51 H4708D8001 Set screw 2 2 SM1/4(24)×13
D52 H7905E8001 Lifting presser 1
D52 H7105E8001 Lifting presser 1
D53 HE204I8001 Finger gusrd 11
D. PRESSER FOOT MECHANISM
—15 —

E. THRED TAKE-UP LEVER & NEEDLE BAR MECHANISM
— 16 —

Fig.
No. Part No. Description
GC24698-25R
GC24698-25L
Remarks
E. THRED TAKE-UP LEVER & NEEDLE BAR MECHANISM
E01 H24211DN05 Oil wick 11
E02 H4706F8001 Needle bar guide bracket stud 11
E03 H4707F8001 Screw 1 1 5/16（28）×10.4
E04
E05
E06
E07
E08
E09
E10
E11
E12
E13
E14
E15
E16
E17
E18
E19
E20
E21
E22
HA100C2020
H24211DN05
H24211DM05
H3504B0651
H2405D1112
HA110D0672
H24211D405
H24211D305
H2405D0662
H4716F8001
H4717F8001
H4719F8001
H32111D304
H4721F8001
H3204D6513
H4722F8001
H32111D604
H4806F8001
H4725F8001
Set screw
Oil wick
Thread take-up lever support stud
Thread take-up lever
Thread take-up slide brock
Screw
Oil wick
Plug
Needle bar crank pin
Oil wick
Needle bar connecting link
Needle bar rock frame
Screw
Washer
Felt
Needle bar connecting stud
Screw
Needle bar
Vibrating presser bar
1
1
1
1
1
1
1
1
1
1
1
1
6
2
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
6
2
1
1
1
1
1
15/64（28）×10
15/64（28）×12
3/32（56）×4
9/64（40）×8.5
E23
E24
E25
E26
E27
H3400C2020
H3200I2030
H3400C2010
H4726F8001
H4753E8001
Bolt
Washer
Needle bar guide
Vibrating presser bar link
Screw
1
2
1
11
11
11
2 11/64（40）×17.5
E28
E29
E30
E31
H4728F8001
H4729F8001
H4730F8001
H3410C301P
Vibrating presser bar guide
Spring
Vibrating presser spring guide
Square block
1
1
1
1
1
1
1
1
E32
E33
E34
E35
H3406C0671
H3406C0672
H4734F8001
H3204B0652
Screw
Needle bar vibrating crank(left)
Washer
Bushing
1
1
1
2
1
1
1
2
15/64(28)×10
E36
E37
E38
E39
E40
H602040240
H7004F8001
H7107F8001
H2012N0652
H7108F8001
Taper pin
Needle bar vibrating shaft
Nut
Screw
Screw
1
1
1
1 GB/T117 4×24
11
11
1 1/4（24）×16
1 5/16（24）×5
E41
E42
E43
H32311D406
H7104F8001
H7105F8001
Oil wick
Needle bar vibrating crank(right)
Connecting link
1
1
1
1
1
1
—17 —

Fig.
No. Part No. Description
GC24698-25R
GC24698-25L
Remarks
E44 H3129F0693 Thread guide 11
E45 HA100C2170 Screw 1 1 1/8（44）×4.5
E46 H3129F0691 Screw 1 1 3/32（56）×2.5
E47 H7106F8001 Vibrating presser foot 11
E48 HA700F2100 Screw 1 1 11/64（40）×7
E. THRED TAKE-UP LEVER & NEEDLE BAR MECHANISM
—18 —