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JUKI LH-4128 Instruction Manual

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ENGLISH
LH-4128, 4128-7
LH-4168-7, 4188-7
INSTRUCTION MANUAL

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Summary of Contents for JUKI LH-4128

  • Page 1 ENGLISH LH-4128, 4128-7 LH-4168-7, 4188-7 INSTRUCTION MANUAL...

  • Page 2: Table Of Contents

    5-6. One-touch reverse feed switch lever (for touch-back) ................... 25 6. MAINTENANCE ......................25 6-1. Changing procedure to bottom feed and the adjustment (LH-4128 without thread trimmer only)..... 25 6-2. Changing procedure to needle feed (for LH-4128 only) ................. 27 6-3.

  • Page 3: Specifications

    2 mm by knee lfter, 5.5 mm by hand lfter lever, 9 mm by knee lfter wth wper Lubrcaton New Defrx Ol No.  • LH-4128 / 4128-7 - Equvalent contnuous emsson sound pressure level (L ) at the workstaton : A-weghted value of 83.5 dB ;...

  • Page 4: Name Of Each Component

    2. NAME OF EACH COMPONENT !5� 1 Separately drven needle 6 Pedal !1 Bobbn wnder changeover swtch 7 Knee lfter lever !2 Thread stand 2 Thread take-up cover 8 Power swtch !3 Ol supply openng 3 Fnger guard 9 Hand swtch !4 Reverse feed control lever 4 Thread tenson controller !0 Operaton panel...

  • Page 5: Installation

    3. INSTALLATION 3-1. Installing the bottom cover The bottom cover should rest on the four corners of the machne table groove. Fx two head support rubber seats 1 on the front sde A to the protrudng secton of the 23.5 mm 19.5 mm machne table usng nals 2 .

  • Page 6: Opening And Closing Of The Control Box (Sc-910)

    In case the AK-devce s not provded, attach head support rod 9 to the machne table. Place urethane filter !0 on A . Then put sheet- metal (fine-mesh sheet) type filter !1 on the urethane filter. Place sheet-metal (fine-mesh sheet) type filter !2 on B .

  • Page 7: Adjusting The Height Of The Knee Lifter

    3-3. Adjusting the height of the knee lifter WARNING : Turn OFF the power before starting the work so as to prevent accidents caused by abrupt start of the sewing machine. The standard heght of the presser foot lfted usng the knee lfter s 2 mm. You can adjust the presser foot lft up to 3 mm usng knee lfter adjust screw 1 .

  • Page 8: Connecting The Cord

    3-6. Connecting the cord (1) LH-4128,4128-7,4168-7,4188-7 Pass the cords 1 of the thread trmmng solenod, reverse-sttchng solenod, etc., and the cords of the synchronzer 2 , safety swtch 3 , machne head 4P connector 4 , motor sgnal 5 , motor output 6 through hole A n the table to route them down under the machne table.
  • Page 9 Optional unit A @5� (2) 4168-7,4188-7 In addton to “3-6. (1)”, connect the cords below. Pass separately drven needle changeover swtch cord @1 , separately drven needle solenod cord @2 and separately drven needle sensor cord @3 through hole A n the table to route them down under the machne table.

  • Page 10: Managing The Cord

    3-7. Managing the cord Fx all cables comng from the machne head wth cable clp band B attached to te-mount [Connection of the connector for CP panel] Exclusve connectors are prepared for connecton of the connector for CP-60. Payng attenton to the orentaton of the connector, connect t to connector !4 located on the crcut board.
  • Page 11 Close front cover !5� whle payng attenton to pnchng of the wre. Lghtly press porton B and nsert front cover !5� wth “clck”. After that, fix it with the screw !2 . !5� Connect motor output cord 6 to connector !6 located on the sde of the box.

  • Page 12: Adjusting The Knee Lifter Detection Seat (Asm.)

    3-8. Adjusting the knee lifter detection seat (asm.) Turn ON the power. Conditions : LED starts lighting at presser Press knee p ad plate 7 and lft the presser foot lift of 5 mm. foot by 5 mm from the top surface of throat plate.

  • Page 13: Preparation Of The Sewing Machine

    • When you use a new sewing machine or a sewing machine after an extended period of disuse, use the sewing machine after performing break-in at 3,000 sti/min or less. • For the oil for hook lubrication, purchase JUKI New Defrix Oil No. 1 (Part No. : MDFRX1600C0).

  • Page 14: Cleaning The Filter

    4-2. Cleaning the filter Lubrication to hook Circulation Plunger Lubrication Circulation To ensure longer service life of your machine, be sure to periodically (approximately once every three months) clean up the above-stated filter section (urethane filter , circulation filter , plunger filter and plunger filter 2 ).

  • Page 15: Adjusting The Amount Of Oil In The Hook

    Loosen needle clamp screws 2 and pck up two needles 1 n the way that ther grooves 3 are facng outwards. Insert the needles nto the needle clamp as far as they wll go. Tghten needle clamp screws 2 firmly. LH-4128, 4128-7 – 3 –...

  • Page 16: How To Take Out The Bobbin Case

    nsde. Put the thread on bobbn threads slack preventer sprng 4 . [LH-4128 and 4128-7] LH-4128, 4128-7 Set a bobbn to the bobbn case so that the bobbn turns n the drecton of arrow mark A.

  • Page 17: Threading The Machine Head

    4-7. Threading the machine head WARNING : Turn OFF the power before starting the work so as to prevent accidents caused by abrupt start of the sewing machine. LH-4188-7 Intermediate thread guide !1 - L !2 - M !3 - N 8 - I !5�...

  • Page 18: Thread Tension

    4-8. Thread tension Needle thread tenson Bobbn thread tenson Turn thread tenson nut No. 2 1 clockwse to Turn tenson adjustng screw 2 clockwse to ncrease or counterclockwse to reduce the ncrease or counterclockwse to reduce the needle thread tenson. bobbn thread tenson.

  • Page 19: Adjusting The Stitch Length

    (2) When you want to change the tension of the thread take-up spring Tenson of thread take-up sprng 1 on the rght s adjustable by turnng sprng stud !3 to the rght to ncrease or to the left to reduce. Tenson of thread take-up sprng 4 on the left s adjustable by turnng sprng stud !4 to the rght to ncrease or to the left to reduce.

  • Page 20: Winding The Bobbin Thread

    4-11. Winding the bobbin thread Insert the bobbn deep nto the bobbn wnder spndle 1 untl t wll go no further. Pass the bobbn thread pulled out from the thread tenson controller located on the rght sde of the thread stand as shown n the fgure and wnd clockwse the end of the bobbn thread on the bobbn several tmes.

  • Page 21: Adjusting The Needle Stop Position

    4-12. Adjusting the needle stop position WARNING : Turn OFF the power before starting the work so as to prevent accidents caused by abrupt start of the sewing machine. (1) Stop position after thread trimming The standard needle stop poston s obtaned by algnng marker dot A on the pulley cover wth whte marker dot B on the handwheel.

  • Page 22: Pedal Pressure And Pedal Stroke

    4-13. Pedal pressure and pedal stroke WARNING : Turn OFF the power before starting the work so as to prevent accidents caused by abrupt start of the sewing machine. (1) Adjusting the pressure required to depress the front part of the pedal Ths pressure can be adjusted by alterng the poston of lever 4 of pedalng pressure adjust sprng 1 .

  • Page 23: Oparation Of The Sewing Machine

    5. OPARATION OF THE SEWING MACHINE 5-1. Pedal operation The pedal is operated in the following four steps: The machne runs at low sewng speed when you lghtly depress the front part of the pedal. The machne runs at hgh sewng speed when you further depress the front part of the pedal.

  • Page 24: Hand Lifter

    5-2. Hand lifter When you want to keep the presser foot n the lfted poston, turn hand lfter 1 n the drecton of the arrow. By so dong, the presser foot rse 5.5 mm. When you want to lower the presser foot, lower the hand lfter.

  • Page 25: Thread Tension Release Changeover When Using The Knee Lifter

    5-4. Thread tension release changeover when using the knee lifter For LH-428-7, LH-468-7, LH-488-7 the knee lfter or AK devce s not nterlocked wth the thread tenson release of thread tenson controller at the tme of delvery. When releasng the thread tenson, press lever 1 to rse the dsks.

  • Page 26: Separately Driven Needle Changeover Switch (For Lh-4168-7 And 4188-7)

    5-5. Separately driven needle changeover switch (for LH-4168-7 and 4188-7) 1 Left-hand needle changeover swtch When ths swtch s pressed, left-hand needle goes up. When t s pressed agan, the needle comes down. Separately 2 Rght-hand needle changeover swtch driven When ths swtch s pressed, rght-hand needle changeover...

  • Page 27: One-Touch Reverse Feed Switch Lever (For Touch-Back)

    Release the swtch lever for forwatd sewng. 6. MAINTENANCE 6-1. Changing procedure to bottom feed and the adjustment (LH-4128 without thread trimmer only) Prepare the gauge for bottom feed. Temporarily set needle rocking rod fixing base 1 contaned n the accessores to hole 2 of the machne frame wth washers 3 and setscrews 4 .
  • Page 28 Loosen nut 5 after adjustng the feed dal to “0”, move needle bar rockng rod 6 from needle bar rockng rod arm 7 to needle rocking rod fixing base 1 , and fix it with nut 5 . After replacng the feed dog and the throat plate wth the components for bottom feed, adjust the position of needle rocking rod fixing base 1 so that the needle center algns wth...

  • Page 29: Changing Procedure To Needle Feed (For Lh-4128 Only)

    6-2. Changing procedure to needle feed (for LH-4128 only) The procedure s the reverse of “6-. Changng procedure to the bottom feed”. Loosen nut 5 , move needle bar rockng rod 6 from needle rocking rod fixing base 1 to needle bar rockng rod arm 7 , and temporarily fix it with nut 5 .

  • Page 30: Adjusting The Inner Hook Guide

    Turn OFF the power switch and ascertain that the motor totally stopped before starting the work so as to prevent personal damage caused by abrupt start of the sewing machine. [LH-4128, 4128-7 and 4168-7] LH-4128, 4128-7, 4168-7 Standard adjustment value of the openng of the nner hook stopper s 0.3 mm.

  • Page 31: Needle-To-Hook Relation

    6-4. Needle-to-hook relation [ LH-4168-7, 4188-7 ] Determne the heght of needle. Set the sttch dal to 2.5 on the scale. Turn the handwheel to brng the needle bar to the lowest poston. Remove cap 1 , loosen setscrews 2 n needle drve arms 3 , adjust engraved marker lnes 5 -A whch are the fourth from the bottom of needle bars 4 to the bottom end...
  • Page 32 [Reference dimension] Needle clamp height at needle bar lower dead point S, F type G type Throat plate Throat plate installing plane installing plane LH-428, 428-7 LH-468-7 S type LH-468-7 G type LH-488-7 Dmenson A 5. ± 0.5 mm 5.8 ± 0.5 mm 4.6 ±...
  • Page 33 [ LH-4128, LH-4128-7 ] Determne the needle bar heght. Set the sttch dal to 2.5 on the scale. Turn the handwheel to brng the needle bar to the lowest poston. Then, loosen needle bar connectng stud clampng screw 1 .

  • Page 34: Adjusting The Height And The Inclination Of The Feed Dog

    C of feed bar arm algns wth engraved marker dot B of feed bar shaft. (Engraved marker dot A s for LH-3500.) · LH-488-7 : Engraved marker lne s level. [LH-4128, 4128-7, 4168-7] [LH-4188-7] Level 6-6. Adjusting the presser foot Confirm the grounding when replacing the presser foot.

  • Page 35: Move (Adjustment) Of The Hook Shaft Saddle When Replacing The Gauge

    6-7. Move (adjustment) of the hook shaft saddle when replacing the gauge Move of the hook shaft saddle when replacng the gauge can be performed wth ease by only loosenng screws 1 and 2 . It s not necessary to re-adjust the hook tmng. 6-8.

  • Page 36: Adjusting The Position Of The Moving Knife

    6-9. Adjusting the position of the moving knife Algn counter knfe base 1 wth plane A of counter knfe 2 . Loosen clamp screw 3 located n the rear of machne bed and adjust so that dstance 2 between the top end of movng knfe B at the tme of watng and the top end of counter knfe 4 s dmenson B.

  • Page 37: Replacing The Bobbin Thread Slack Preventer Spring (For Lh-4168-7 And 4188-7)

    6-10. Replacing the bobbin thread slack preventer spring (for LH-4168-7 and 4188-7) Loosen screw 1 and remove bobbn thread slack preventer sprng 2 from the groove on the bobbn case. Ft bobbn thread slack preventer sprng 2 whch replaces the removed sprng n the bobbn case through the groove.

  • Page 38: Stop Of The Needle Bars And Angle Of Corners For Corners Stitching (For Lh-4168-7 And 4188-7)

    6-12. Stop of the needle bars and angle of corners for corners stitching (for LH-4168-7 and 4188-7) (1) Stop of the needle bars When separately drven needle changeover swtch 1 s pressed durng sewng, the left-hand needle bar stops, and when 2 s pressed, the rght-hand needle bar stops.

  • Page 39: Position Of The Wiper

    OFF the power. Otherwise, error No. E220 or error No. E221 is displayed again. 2. For replenishing grease to the specified places below, use JUKI GREASE A TUBE (Part No. 40006323) or JUKI GREASE B TUBE (Part No. 40013640) supplied as accessories.
  • Page 40 WARNING : Turn OFF the power before starting the work so as to prevent accidents caused by abrupt start of the sewing machine. (1) Replenishing grease to the needle bar drive cam section Remove the top face cover, and remove the rubber caps attached to the npples 1 .

  • Page 41: Cleaning The Inside Of The Needle Bar Bushing

    6-16. Cleaning the inside of the needle bar bushing WARNING : Turn OFF the power before starting the work so as to prevent accidents caused by abrupt start of the sewing machine. [ LH-4168-7, LH-4188-7 ] Insde of the needle bar bushng should be cleaned once every sx months. Tlt the sewng machne.

  • Page 42: Stitch-To-Angle Table By Gauge (Pitch And Mm Conversion Table)

    7. STITCH-TO-ANGLE TABLE BY GAUGE (PITCH AND mm CONVERSION TABLE) /8"(3.7mm) 5/32"(3.96mm) Number of Number of sttches sttches Turnng Turnng angle angle 3/6"(4.76mm) 7/32"(5.56mm) Number of Number of sttches sttches Turnng Turnng angle angle /4"(6.35mm) 9/32"(7.4mm) Number of Number of sttches sttches Turnng...

  • Page 43: Gauge Sets

    8. GAUGE SETS (1) LH-4128 Throat plate Throat plate Needle gauge Feed dog (Throat feed) (Lower feed) Cord 1 . 7 1 . 9 2 . 2 m m nch Ref.No. P a r t N o . Ref.No. P a r t N o .
  • Page 44 Needle gauge Needle clamp asm. Presser foot asm. (Tip - divided) (Tip - divided) (Lower feed) Cord (Wire Type) (Hole Type) nch Ref.No. P a r t N o . Ref.No. P a r t N o . P a r t N o .
  • Page 45 (3) LH-4128-7 Needle gauge Throat plate Feed dog Presser foot asm. (Tip - divided) (Tip - divided) 3 . 2 m m 1 . 9 1 . 7 Cord (Option) nch R e f . N o . R e f . N o .
  • Page 46 (4) LH-4168-7 Needle gauge Throat plate Feed dog Presser foot asm. (Tip - divided) (Tip - divided) 3 . 2 m m 1 . 9 1 . 7 Cord (Option) nch Ref.No. Ref.No. P a r t N o . Ref.No.
  • Page 47 (5) LH-4188-7 Needle gauge Throat plate Feed dog Presser foot asm. (Tip - divided) (Tip - divided) 2 . 4 1 . 9 Cord 3 . 2 m m nch Ref.No. P a r t N o . Ref.No. P a r t N o .

  • Page 48: Troubles And Corrective Measures

    9. TROUBLES AND CORRECTIVE MEASURES TROUBLES CAUSES CORRECTIVE MEASURES Thread 1 There s a sharp edge or burr on the ™ Remove sharp edge or burr using a fine breakage thread path, needle pont, hook blade sandpaper. Polsh the surface of the (Thread s pont or bobbn case restng groove on bobbn case restng groove on the throat...

This manual is also suitable for:

Lh-4188-7Lh-4128-7Lh-4168-7

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