JUKI LK-1900AN Engineer's Manual page 57

Adjustment procedures
1. If the dimensions of 0.3 x 8 mm are not secured, retouching is
required with the aid of an oil stone.
Dimension A
Part No.
(mm)
0.8 14103253
1.3 14103352
1.7 14103659
1.9 B1817210DAD
Adjustment procedures
The standard stroke of thread take-up spring 1 is 8 to 10 mm, and
the pressure at the start is 0.1 to 0.3N.
1) Adjusting the stroke
Loosen setscrew 2 , and turn thread tension asm. 3 .
Turning it clockwise will increase the moving amount and the
thread drawing amount will increase.
2) Adjusting the pressure
To change the pressure of the thread take-up spring 1 , insert
a thin screwdriver into the slot of thread tension post 4 while
screw 2 is tightened, and turn it. Turning it clockwise will in-
crease the pressure of the thread take-up spring 1 . Turning it
counterclockwise will decrease the pressure.
Example of the thread tension
When using the sewing machine for the first time, adjust the thread
tension referring to the table below.
Thread
Tetoron thread #50 Wool
Spun thread #50 Wool
Spun thread #60
T/C broad
(Thread clamp OFF)
Cotton thread #50 Denim
Cotton thread #20 Denim
Name of part
Inner hook
presser A
Inner hook
presser B
Inner hook
presser C
Inner hook
presser D
Needle thread
Material
tension setting
30 to 35
50 to 55
30 to 35
35 to 45
35 to 45
Results of Improper adjustment
Remarks
Conforming to
Specifications F
and M as stan-
dard
Conforming to
Specifications S
as standard
Conforming to
Specifications
H as standard
Optional
Results of Improper adjustment
Thread take-up spring moving amount
[Thread drawing amount]
10 mm [13 mm]
10 mm [13 mm]
8 to 10 mm [11 to 13 mm]
10 mm [13 mm]
8 to 10 mm [11 to 13 mm]
– 45 –
Strength
0.1N
0.2N
0.1N
0.1N
0.1N