JUKI MO-6800S Series Engineer'S Manual Download Page 36

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(14) Replacing the upper and lower knives and adjusting the overedging width

WARNING :

Turn OFF the power before starting the work so as to prevent accidents caused by abrupt start of the

sewing machine.

Standard adjustment

1) Replace the upper knife
2) Replace the lower knife
3) Adjusting the overedging width
4) Resharpening of the knife

0.5 to 1.0mm

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62°

15°

Summary of Contents for MO-6800S Series

Page 1: ...40159525 No E419 02 ENGINEER S MANUAL High speed Overlock Safety Stitch Machine MO 6800S Series...

Page 2: ...d other important information which are not covered in the Instruction Manual When carrying out the maintenance work on the sewing machine be sure to refer also to the Instruction Manual and the Parts...

Page 3: ...eedle changing bobbin changing or oiling and cleaning Electrical shock danger label DANGER This indication is given where there is an immediate danger of death or serous injury if the person in charge...

Page 4: ...eath JUKI assumes no responsibility for damages or personal injury or death resulting from the machine which has been modified or altered Education and training 1 In order to prevent accident resultin...

Page 5: ...rth cable in order to prevent accident caused by earth leakage IV Motor 1 Be sure to use the specified rated motor JUKI genuine product in order to prevent accident caused by burnout 2 If a commercial...

Page 6: ...t that can result in personal injury or death 9 Be sure to periodically clean up the air vent of the fan and inspect the area around the wiring in order to prevent fire accident of the motor 10 In ord...

Page 7: ...to protect against accident that can result in personal injury In addition be sure to select appropriate tools 3 In prevention of accident that can result in personal injury make sure after the comple...

Page 8: ...ne parts when replacing any of the machine parts JUKI assumes no responsibility for any accident caused by any part other than JUKI genuine one In addition in the event you cannot replace parts within...

Page 9: ...pecified After the completion of assembly work be sure to check that screws and nuts are not loosened before starting test run 6 In prevention of accident that can result in personal injury make sure...

Page 10: ...t start of the ma chine make sure to turn OFF the power to the machine when you leave your machine 9 In the event of a power failure be sure to turn OFF the power to the machine to protect against pos...

Page 11: ...ON BEFORE OPERATION Read and understand well the content of this instruction book Know the functions of major parts and understand the notices Truely realize the meanings of all warning tags Realize a...

Page 12: ...adjusting the overedging width 24 1 Replace the upper knife 24 2 Replace the lower knife 24 3 Adjusting the overedging width 24 4 Resharpening of the knife 24 15 Adjusting the thread cam equipment Ap...

Page 13: ...Lower bushing type 11 Needle DC 27 Standard Excluding some of subclass machines 12 Presser lifting amount 5 to 7 mm 13 Presser foot pressure 44 1 N 4 5 kg 30P 36 5 N 3 7 kg 60H 54 N 5 5 kg 14 Stitch a...

Page 14: ...2 2 Names of major parts Presser foot lifting lever Presser foot asm Thread stand Oil gauge Pulley Cloth plate cover...

Page 15: ...ight materials such as denim or the like 6 Heavy weight materials 9 Overedging width code A 1 5 mm D 3 0 mm E 4 0 mm F 5 0 mm H 6 0 mm In the case that the machine code is 6845 it is possible to use F...

Page 16: ...machine MO 6814S 2 H 9 1 MO 6814S 3 H MO 6814S 4 H 11 8 12 10 5 MO 6814S 30P 10 4 10 6 9 1 Safety stitch machine MO 6816S 3 H 7 6 MO 6816S 50H 11 8 12 9 MO 6816S 60H 12 6 12 8 9 8 MO 6816S 30P 10 4 10...

Page 17: ...crank to turn until it settles by itself Then tighten the clamping screw to fix the forked crank at that posi tion o Any other needle height than specified here will badly affect the action of the low...

Page 18: ...rlock machine MO 6814S 2 H MO 6814S 3 H MO 6814S 4 H 4 1 4 3 MO 6814S 30P 3 7 3 9 Safety stitch machine MO 6816S 3 H MO 6816S 50H 4 1 4 3 MO 6816S 60H MO 6816S 30P 3 7 3 9 Caution The dimensions given...

Page 19: ...forth Turn fine adjustment screw clockwise to move lower looper away from the needle Turn it counterclockwise to move lower looper closer to the needle o Excessive returning amount of the lower looper...

Page 20: ...rface A of the frame and the upper end of the upper looper holder pin should be as shown below when the upper looper holder is at the highest point of its stroke Unit mm Model H 1 needle overlock mach...

Page 21: ...dimension H from the bottom surface A of the frame to the top surface of upper looper holder pin before tightening the clamping screw of the upper looper ball arm Refer to 4 19 Positioning the upper...

Page 22: ...ck machine MO 6804S 10 8 4 8 5 2 2 needle overlock machine MO 6814S 2 H 10 5 5 4 5 7 MO 6814S 3 H MO 6814S 4 H 12 MO 6814S 30P 10 5 Safety stitch machine MO 6816S 3 H 10 8 4 8 5 2 MO 6816S 50H 12 MO 6...

Page 23: ...ion ing the clearance of 0 05 to 0 2 mm between the upper looper and the lower looper at the time of their crossing Caution The upper looper and the lower looper shall not either touch nor collide to...

Page 24: ...S 30P 1 4 1 9 Caution The dimensions given in the table are standard ones to be used to adjust the looper They are intended to be used for reference and should be changed more or less in accordance wi...

Page 25: ...ce between the double chain looper and the needle 1 Loosen clamping screw of double chain lopper driving arm 2 Turn fine adjustment screw to adjust the clearance by moving double chain lopper driving...

Page 26: ...edle bend needle by 0 to 0 05 mm when the needle left needle for the 2 needle model is at the lowest point of its stroke The clearance between needle guard and the needle is 0 1 to 0 2 mm when the nee...

Page 27: ...ance between the needle guard and the needle will cause the blade point of looper to come in con tact with the needles leading to needle or blade point break age or other troubles o Excessive clearanc...

Page 28: ...ent accidents caused by abrupt start of the sewing machine Standard adjustment 9 Adjusting the tilt of the feed dog WARNING Turn OFF the power before starting the work so as to prevent accidents cause...

Page 29: ...high the needles will be deflected and broken when sewing heavy weight materials The feed dogs will tend to suffer scratches when sewing light weight mate rials Puckering will frequently occur o If th...

Page 30: ...1 7 Stretching 1 0 9 Max Gathering 1 4 Stretching 1 0 6 11 Longitudinal position of the main feed dog WARNING Turn OFF the power before starting the work so as to prevent accidents caused by abrupt st...

Page 31: ...mm 60H 21 5 mm 4 When adjusting the maximum stretching adjust main feed pin differential feed adjusting lever to the highest position 5 When adjusting the maximum gathering adjust main feed pin diffe...

Page 32: ...rn OFF the power before starting the work so as to prevent accidents caused by abrupt start of the sewing machine Standard adjustment 1 Adjusting the presser foot position 2 Adjusting the lift amount...

Page 33: ...of the presser foot 1 Turn the pulley to lower the feed dog until the bottom of the presser foot horizontally comes in contact with the throat plate 2 Provide a 1 mm clearance between presser foot lif...

Page 34: ...FF the power before starting the work so as to prevent accidents caused by abrupt start of the sewing machine Standard adjustment The upper knife shaft should be positioned 24 mm above the top surface...

Page 35: ...n from the top surface of the throat plate to 24 mm Caution Be sure to fully tighten the clamping screw since the upper knife shaft is subjected to high load o Improperly positioned upper knife arm sh...

Page 36: ...h WARNING Turn OFF the power before starting the work so as to prevent accidents caused by abrupt start of the sewing machine Standard adjustment 1 Replace the upper knife 2 Replace the lower knife 3...

Page 37: ...dead point 2 Loosen the screw and move the lower knife holder to the left Then tighten the screw a little 3 Loosen the screw and move the upper knife holder left or right till reaching the desired wi...

Page 38: ...ing the work so as to prevent accidents caused by abrupt start of the sewing machine Standard adjustment 1 Adjusting the thread cam 2 Adjusting the thread cam thread guides A and B and the thread cam...

Page 39: ...nail with setscrew so that the straight section of the forked portion is leveled 3 Positioning the chain looper thread guide 1 Fix the chain looper thread guide by the setscrew so that a thread path...

Page 40: ...osing looper cover with upper knife in its lowest position of its stroke 17 Adjusting the cloth chip cover WARNING Turn OFF the power before starting the work so as to prevent accidents caused by abru...

Page 41: ...ct with looper cover receiving bracket Now fix the guide plate by tightening setscrew Adjustment procedures Results of Improper adjustment 1 Loosen the setscrew 2 Turn the stopper screw to adjust a lo...

Page 42: ...e bar lubricating pin WARNING Turn OFF the power before starting the work so as to prevent accidents caused by abrupt start of the sewing machine Standard adjustment 0 1 to 0 3mm Thickness gauge 0 1 t...

Page 43: ...needle bar stroke 4 Tighten the setscrew 60H 1 Bring the needle bar to the lower dead point 2 Loosen the setscrew 3 Adjust a position of the needle bar lubricating pin so that a clearance provided be...

Page 44: ...tandard adjustment 1 Orientation of the lubricating pin Oil inlet A of upper looper lubricating pin should face upward A B 2 Setting the lubricating pin The clearance provided between upper looper lub...

Page 45: ...nt part of the oil wicks in the upper loop er holder pin should face to the side of the upper looper lubricating pin In addition the oil wicks should not be hubbly to the end face B of the upper loope...

Page 46: ...to prevent accidents caused by abrupt start of the sewing machine Standard adjustment 1 Positioning the needle thread take up lever and the needle thread guide MO 6804S MO 6814S MO 6816S 6mm 5 5mm 7...

Page 47: ...take up lever and the needle thread guide Unit mm MO 6814S MO 6816S A B C A B C D Excluding 30P and 60H 6 5 6 5 5 8 5 8 14 12 30P 6 5 6 5 5 11 5 11 13 13 60H 7 5 8 14 13 2 Positioning the looper threa...

Page 48: ...cation and drainage WARNING Turn OFF the power before starting the work so as to prevent accidents caused by abrupt start of the sewing machine Standard adjustment 1 Lubrication oil 2 Drainage and ref...

Page 49: ...er lines on the oil gauge tighten the oil sight window 2 Before using a new sewing machine for the first time after the purchase or the sewing machine which has not been used for an extended period of...

Page 50: ...en the frame and the upper looper guide support section in the illustration Be careful not to allow the sealant to run to the rear Apply a sealant to bottom surface Apply a sealant to bottom surface M...

Page 51: ...lane D of the feed mechanism cover Apply a sealant evenly to the portion of feed bar presser E of the feed mechanism cover Side cover Apply a sealant evenly to the mounting plane F of the side cover D...

Page 52: ...r belt is that the belt can be pressed in about 10 mm by a finger 3 Refer to the table shown below for the size of pulley and the sewing speed The above applies to both the machine with table fixed ty...

Page 53: ...00265 1 Fully sunken type Support plate bolt set asm 70000884 1 To extend the usage term this machine has equipped an oil filter Clean up this oil filter once every month and change it with a new one...

Page 54: ...tilting or returning it to its original position If only using one hand to move the machine the weight of the machine head may cause slipping and you may get hurt Maintenance Cycle Maintenance Items...

Page 55: ...1 5 9 8 3 9 4 0 1 5 9 8 3 9 4 0 1 5 9 8 4 0 7 0 0 7 8 5 9 2 4 0 1 5 9 8 4 9 4 0 1 7 8 5 9 5 7 0 0 0 0 7 9 9 7 0 0 0 0 8 0 4 7 0 0 0 0 8 0 4 D C X 2 7 1 6 2 D C X 2 7 2 1 2 D C X 2 7 1 6 2 7 0 0 0 0 8...

Page 56: ...ht of pin Center to center A B C D E H I F J G K 1 needle over lock machine MO 6804S 10 4 10 6 10 8 4 8 5 2 48 4 39 0 3 7 3 9 68 1 2 needle over lock machine MO 6814S 2 H 9 1 10 5 5 4 5 7 50 3 MO 6814...

Page 57: ...needle is too thin for the thread Replace the needle by a proper one 1 5 Needle heat 5 A The needle gets very hot depending on the type of materials number of plies and sewing speed and causes the thr...

Page 58: ...ke up 2 A The looper thread take up or thread guide has been improperly positioned causing excessive thread tension Refer to the pertinent Standard Adjustment 2 3 Thread tension 3 A The looper thread...

Page 59: ...has been improperly positioned causing the needle point to strike it Refer to the pertinent Standard Adjustment 3 5 Needle No 5 A The needle is too thin for the materials Replace the needle with a thi...

Page 60: ...eedle or DC 1 is used Replace the bent needle Correctly orient and attach the needle Use a DC 27 needle Use a DC J27 needle for a stretchy thread 5 5 Needle guards 5 A Incorrect height or clearance pr...

Page 61: ...amount 5 A Too much lower looper thread is fed giving slack of thread Slightly lower the looper thread take up left to decrease the amount of thread Slightly raise the looper thread take up right to...

Page 62: ...ent Standard Adjustment 8 2 Needle 2 A The needle is bent or attached with wrong orientation DC 1 needle is used Replace the bent needle Remove the cause for the needle bend Correct the orientation of...

Page 63: ...sion a little 9 6 Threading 6 A The area around the thread cam has threaded erroneously Correct the threading 10 Triangle double chain needle thread stitches are skipped The needle fails to catch the...

Page 64: ...Adjustment of loopers for producing chain off thread without materials re quires higher accuracy Refer to the pertinent Standard Adjustment 11 4 Thread tension 4 A The thread tension is too low Sligh...

Page 65: ...nt of the double chain looper or cam timing is early or wrong threading Refer to the related Standard Adjustment for the returning amount of the double chain looper or cam timing See the threading dig...

Page 66: ...shown below 15 1 Looper thread ten sion 1 A The upper and lower looper thread ten sions are not enough Slighrly increase the upper and lower looper thread tensions 15 2 Looper thread take up 2 A The l...

Page 67: ...n done erroneously Refer to the threading diagram 19 2 Adjustment of the looper thread take up 2 A The height of the looper thread take up left is not correct Raise the looper thread take up left to i...

Page 68: ...A The thread cam timing is too late Advance the cam timing Refer to the pertinent Standard Adjustment 21 6 Feed dogs 6 A The leading edge of the feed dog teeth has been rounded off Replace the feed d...

Page 69: ...10 A A 830 550 303 257 205 125 105 60 455 435 590 515 460 335 400 300 255 235 159 105 65 A 19 5 420 355 303 81 185 A 370 1200 773 613 355 255 230 R 4 0 R 4 0 R 2 0 R 4 0 2 R20 R20 R 2 0 45 5 25 5 3 40...

Page 70: ...2 0 830 550 470 303 257 205 125 105 1200 773 613 355 255 230 420 355 303 81 590 515 460 335 400 300 255 235 159 105 65 19 5 10 3 40 12 2 47 4 2 2 5 13 4 10 R20 R 2 0 60 185 A A A A A A Note This part...

Page 71: ...0 10 4 5 40 3 4 28 4 13 3 9 5 13 R R 2 4 8 R 1 0 2 R 5 0 2 R 2 5 4 R 3 0 350 320 283 165 150 120 80 20 455 425 375 350 330 300 265 110 95 85 30 50 80 600 580 575 475 450 340 270 225 690 655 555 535 51...

Page 72: ...206 8551 JAPAN PHONE 81 42 357 2371 FAX 81 42 357 2274 http www juki com An environmental management system to promote and conduct the following 1 Eco friendly development of products and technologies...

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