1. DOUBLE NEEDLE
CHAIN STITCH

2. STITCH CLASS 400 : MULTI THREAD CHAIN STITCH
This stitch type is formed by inter-looping of two or more groups of thread.
Stitch formation in the stitch type 401

4. MACHINE COMPONENTS Thread tension mechanism Thread tension Nut
Tension post holder
Thread Eye-let ( 5 nos. )
Thread take-up plate
Needle Thread Guard
Needle bar and lever Mechanism
Needle lever
Needle Bar guide and clamp
Ball joint

5. Feed Mechanism
Feed-dog
Feed rocker arm
Rear puller
Feed-dog slots
Looper Mechanism
Looper
Looper Rocker
Take-up Rod
Looper Holder Bracket

6. Presser Foot Mechanism Presser Bar Presser Screw Lifter Lever Spring
Presser Foot Lifter Lever
Presser Bar Guide
Presser Bar Spring
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7. NEEDLES Schmetz- UY113GS Organ – UO113GS Groz-beckert- TVx64
Needles and needle sizes
Schmetz
UY113GS
Nm 75
Nm 80
Nm 90
Nm 100
Organ
UO113GS
#11
#12
#14
#116

8. THREADING Threading of the machine is very important
Incorrect threading may cause:
Skip stitch
Thread breakage
Uneven stitch formation

9. MACHINE SPEED Chain stitch machine can have a speed up to 8000rpm
Model
Max. speed
Standard speed
DBF1404P
4500
4000

10. FEED MECHANISM Unison Feed Mechanism:
It is a combination of three feed mechanisms
Conventional feed mechanism
Needle feed mechanism
Alternating presser foot

11. TIMING OF THE LOOPER TO NEEDLES
Angle for installing the looper and position of the looper holder bracket
There should be a clearance of 0~0.1mm between the point of the looper and the scarf of the needle

12. LOOPER LEFT – RIGHT MOVEMENT and LOOPER SETTING DISTANCE

13. ADJUSTING THE TIMING OF THE RETAINER LOOPER
Position of the retainer loop
There should be a clearance of 0.5mm between the needle and the point of the retainer looper. Adjustment is made by loosening b as shown in the fig.

14. Timing of the retainer looper to the needle
When the needle, moving from top to bottom of
Its stroke, enters the triangle of the looper thread, the retainer Looper should be at the extreme right end of its travel
The clearance between the retainer looper and the right side of looper should we 0.5 mm.
The clearance between the retainer looper and the top surface of the looper blade at 0.1mm

15. ADJUSTING THE NEEDLE GUARD
Position of the needle guard
When the needle is closest to needle guard, there should be clearance of 0~0.1mm between the right side of the needle and the guard.

16. ADJUSTING THE FEED DOG & STITCH LENGTH
When needle bar is at top of its stroke, the feed dog teeth should be 1~1.2mm above the top surface of the needle plate.
Stitch length
The stitch length can be adjusted from 2 to 5 mm.
Stitch length (mm)
Number of stitches
Within1”
within 30mm 2 13 15 3
8.5 10 5 6

17. ADJUSTING THE PRESSER FOOT
Presser foot pressure should be as light
as possible yet, sufficient to feed the fabric.
Position of the presser foot
Accurate placement so that the needle can drop correctly
to the centre of the needle drop hole on the presser foot

18. ADJUSTING THE STITCH FORMATION
Thread tension adjustment
It can be adjusted by adjusting the mount tension devices on the machine
( The tension should be as light as possible ).
Position of the needle thread eyelets
Secure needle thread eyelets should be at the top end of the slot.
( The needle thread eyelets can be raised to tighten the needle thread )

19. APPLICATION OF DNCS Inseam of jeans, trousers In Jackets seams
Sewing sides of slacks
Hemming or welting garment parts
Attaching lining tapes
Joining seat of slacks

20. VARIATIONS IN DNCS Variations in bed type
Cylindrical bed- feed of the arm
Raised bed
Flat bed
Variations in number of needles
2 needle double needle chain stitch machine
4 needle double needle chain stitch machine
12 needle double needle chain stitch machine
33 needle double needle chain stitch machine