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 17 

    

10

10

10

10----4 Overlap of the upper and lower knives

4 Overlap of the upper and lower knives

4 Overlap of the upper and lower knives

4 Overlap of the upper and lower knives    

When upper knife J is at the bottom of its stroke, 
adjust the overlap of the upper and lower knives as 
shown in the illustration.    To increase the overlap, 
loosen screw K on the upper knife lever and move 
the upper knife in the direction of arrow X. 
To decrease the overlap, move the upper knife in the 
direction of arrow Y.  When the correct overlap is 
achieved, tighten screw K. 

 
 
 
 
 
 
 

10

10

10

10----5 Adjusting the stroke of the upper knife

5 Adjusting the stroke of the upper knife

5 Adjusting the stroke of the upper knife

5 Adjusting the stroke of the upper knife    

Set the stroke of the upper knife at approximately 
8mm.  To change the stroke, loosen nut L on the 
upper knife adjusting lever pin. 

 

■ 

To decrease the stroke, move lever pin M in the 

direction of Y. 

 

■ 

To increase the stroke, move lever pin M in the 

direction of X. 

 

After the adjustment, tighten nut L securely. 
Adjustment of the stroke will change the overlap of 
the upper and lower knives. 
Be sure to achieve the correct overlap by referring to 
10-4. 

 
 
 
 

10

10

10

10----6 Resharpening the knives

6 Resharpening the knives

6 Resharpening the knives

6 Resharpening the knives    

Since the upper knife is made of a superalloy, there 
is no need to resharpen it about one year. 
If cutting does not occur, resharpen the lower knife. 

 
 
 
 

 

 

 

 

 

 

 

 

 

 

Summary of Contents for DX9900-4U

Page 1: ...INSTRUCTION Industrial Sewing Machines DX9902 3U DX9900 4U First published July 1997 No 970038 ...

Page 2: ...starting the machine check to make sure the pulley cover safety cover etc are secured 3 Before adjusting cleaning threading the machine or replacing the needle be sure to turn off the power 4 Never start the machine with no oil in the reservoir 5 Refer to the parts list as well as this instruction manual before maintenance If the machine includes a thread trimmer read and study the instruction man...

Page 3: ... 12 7 4 Stitch length 12 8 PRESSER FOOT 8 1 Presser foot pressure 13 8 2 Position of the presser foot foot lift 13 9 STITCH FORMATION 9 1 Position of the needle thread guides 14 9 2 Position of the thread guide on the needle thread take up 14 9 3 Timing of the needle thread take up 14 9 4 Position of the thread support 15 9 5 Adjusting the looper thread take up 15 9 6 Adjusting the amount of the l...

Page 4: ...ng the needle 2 Replacing the needle To replace the needle check the needle carefully to see that the scarf is turned to the rear of the machine see the illustration Then install the needle correctly 1 1 1 1 3 Threading the machine 3 Threading the machine 3 Threading the machine 3 Threading the machine Thread the machine correctly by referring to the illustration below Threading the machine incorr...

Page 5: ...machine pulley turns clockwise as the handwheel does as seen from the machine pulley 2 2 2 2 2 Motor belt 2 Motor belt 2 Motor belt 2 Motor belt Motor 3 phase 2 pole 400W clutch motor Belt M type V belt Select the proper motor pulley according to the machine speed refer to the motor pulley outer diameter on the table below Adjust where to position the motor by pressing the finger onto the middle o...

Page 6: ... 3 Replacing the oil and the oil element placing the oil and the oil element placing the oil and the oil element placing the oil and the oil element To extend machine life be sure to replace the oil after the first 250 hours of operation To replace the oil follow the procedures below 1 Remove the V belt from the motor pulley and then remove the machine from the table 2 Remove screw D and then drai...

Page 7: ...4 4 SEWING MACHINE INSTALLATION 4 4 4 4 1 Cutting the machine table 1 Cutting the machine table 1 Cutting the machine table 1 Cutting the machine table ...

Page 8: ...elt cover correctly by referring to the illustration 5 TIMING OF THE LOOPER TO THE NEEDLES 5 5 5 5 1 Angle and height 1 Angle and height 1 Angle and height 1 Angle and height for installing the looper for installing the looper for installing the looper for installing the looper To obtain the proper angle and height insert the looper fully into looper holder A and then tighten screw B The proper an...

Page 9: ...le holding the timing pulley upper by hand 5 5 5 5 3 Looper setting distance 3 Looper setting distance 3 Looper setting distance 3 Looper setting distance Adjustment should be made by referring to looper A When the needle is at the bottom of its stroke with the looper at the extreme right end of its travel setting distance B from the point of the looper to the center of the right needle varies acc...

Page 10: ...ooper front 5 Needle looper front 5 Needle looper front to to to to back relationship back relationship back relationship back relationship 2 3U When point B of the looper reaches left needle C there should be a clearance of 0 2 0 3mm between point B of the looper and left needle C When point B of the looper reaches right needle E they should slightly touch with each other Adjustment is made by lo...

Page 11: ...ight increases Then the point of the looper touches the right needle Skip stitching may occur when the looper moves to the right A thread chain is not produced smoothly When the timing mark is at point D The clearance between the point of the looper and the left needle increases Skip stitching may occur when the looper moves to the left The needle extremely touches the back of the looper causing n...

Page 12: ...e 3 3 5mm The amount of the looper front to back movement is factory set properly for needle count 14 Nm90 If you use needle counts 11 Nm75 adjust the amount as required Remove the inside cover Loosen nut B while holding screw A for the looper front to back adjusting pin with a screwdriver Then move the front to back rod front or back To increase the amount move alignment mark D on the front to ba...

Page 13: ...djustment should be made on other double chainstitch machines These adjustments are made by loosening screws C and D The clearance between the left needle and the needle guard rear should be approximately 0 2mm 6 6 6 6 2 Position of the needle g 2 Position of the needle g 2 Position of the needle g 2 Position of the needle guard rear 004U uard rear 004U uard rear 004U uard rear 004U Height of the ...

Page 14: ...eed dog height tilt 1 Feed dog height tilt 1 Feed dog height tilt 1 Feed dog height tilt Height When the feed dog is at the top of this stroke the feed dog teeth should be parallel with and 1 0 1 2mm above the top surface of the needle plate To make this adjustment loosen screw A and move the feed dog up or down Tilt When the feed dog is at the top of this stroke the feed dog should be parallel wi...

Page 15: ...length is adjustable from 1 4 to4 5mm The following table shows the number of stitches within 1 inch 25 4mm according to the stitch length Stitch length mm No of stitches within 1 4 5 5 5 4 0 6 5 3 0 8 2 0 12 1 0 18 To change the stitch length Turn adjusting knob A or position lever B as required The readings show the stitch length On the DX Series the feeding amount can be changed mechanically up...

Page 16: ...osition of the presser foot foot lift 2 Position of the presser foot foot lift Fit the presser foot onto the presser bar so that the needle can drop correctly to the center of the presser foot needle drop hole Position of the presser foot Loosen screw A Adjust by moving the presser foot left or right while checking to make sure the needle drops correctly to the center of the presser foot needle dr...

Page 17: ...osition of the thread guide on the needle thread take up up up up When the needle bar is at the bottom of its stroke needle thread take up bracket a should be level and the distance from the center of the screw B to the thread guide of needle thread take up A should be 55mm To make this adjustment loosen screws B and C To tighten the needle thread move needle thread take up to Y To loosen the need...

Page 18: ...the looper thread take oper thread take oper thread take oper thread take up up up up When the point of the left needle has reached approximately half of the looper blade from the top of its stoke the looper thread should be removed from the highest point A on the looper thread take up Adjustment is made by loosening screw B 9 9 9 9 6 Adjusting the amount of the looper thread to be supplied 6 Adju...

Page 19: ...lower knife A flush with the top surface of the needle plate Then tighten screw B 2 Loosen screws G on the collar left that was tightened temporarily The upper lower knives are overlapped by the spring pressure 3 Place a thread between the upper and lower knives Check for the cutting action by turning the machine pulley by hand 4 Bring the upper knife to the top of its stroke Tighten screws G on t...

Page 20: ...g the stroke of the upper knife 5 Adjusting the stroke of the upper knife 5 Adjusting the stroke of the upper knife Set the stroke of the upper knife at approximately 8mm To change the stroke loosen nut L on the upper knife adjusting lever pin To decrease the stroke move lever pin M in the direction of Y To increase the stroke move lever pin M in the direction of X After the adjustment tighten nut...

Page 21: ...s 1 Installing the rollers 1 Installing the rollers 1 Installing the rollers Install tension roller bracket A as shown in the illustration Install roller brackets B properly on the underside of the table Install tension bracket C on the underside of the table see the illustration ...

Page 22: ...on may be changed causing trouble 4 When the start of sewing comes close to guide B press the knee switch The fabric is removed from the tape guard and the guide Then keep on sewing while checking the fabric is fed neatly and the start of sewing is aligned with the end of sewing 11 11 11 11 3 Adjusting the rollers 3 Adjusting the rollers 3 Adjusting the rollers 3 Adjusting the rollers Position ten...

Page 23: ...ion each elastic tape so that it cannot touch each needle see the illustration Adjustment is made by loosening screws A from the hole on guide holder upper cover B and moving the guide holder upper to the left or right as required Adjusting the hem width Loosen screws A and B Position fabric guide right C and fabric guide front D according to the hem width Adjustment is made by moving C and D to t...

Page 24: ...the stopper To position or remove the fabric raise hand lever A With the hand lever lowered adjust stopper B so that the clearance between the upper and lower pullers is 0 5mm Then tighten nut C 12 12 12 12 2 To adjust the puller pressure 2 To adjust the puller pressure 2 To adjust the puller pressure 2 To adjust the puller pressure The puller pressure should be as light as possible yet be suffici...

Page 25: ...3 REPLACING THE TIMING BELT 13 13 13 13 1 Marks on the timing belts 1 Marks on the timing belts 1 Marks on the timing belts 1 Marks on the timing belts The X Series is available in timing belts of A B and C according to the distance between the upper and lower shafts A indicates the longest timing belt 13 13 13 13 2 To remove the timing bel 2 To remove the timing bel 2 To remove the timing bel 2 T...

Page 26: ... looper to the extreme right end of its travel by turning the machine pulley Bring the needle bar down to the bottom of its stroke by hand 4 Then place the belt onto the timing pulley on the upper shaft Tighten two screws A 5 Bring the needle bar up to the top of its stroke by turning the machine pulley Check to make sure mark P on the handwheel is aligned with alignment mark O on the bed 6 To mak...

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