JUKI LK-1900B series - ( 41) a Djustment of the Shuttle Upper Spring Position (LK-1903 B-BS, 1900 B-BS, 1900 B-BF, 1903 BN-BS, 1900 BN-BS, 1900 BN-BF) and the Lower Thread Holder Position (LK-1903 BN-BS)

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(41) Adjustment of the shuttle upper spring position (LK-1903B-BS, 1900B-
BS, 1900B-BF, 1903BN-BS, 1900BN-BS, 1900BN-BF) and the lower thread
holder position (LK-1903B-BS, 1903BN-BS)
WARNING :
As the work is performed while the power is ON, never touch the switches other than the necessary
one so as to prevent accidents caused by the malfunction of switches.
Standard adjustment
1. Shuttle upper spring
❷
(LK-1903B-BS, 1900B-BS, 1900B-BF)
In regard to the right and left positioning, secure coincidence between the center of the needle
❺
and
that of the groove width
C
.
For the front-rear positioning, join the rear end of the needle
❺
and the corner portion
A
.
2. Lower thread holder
❸
(LK-1903B-BS)
The amount of overlapping with the shuttle upper spring
❷
should be adjusted so that cotton thread
#30 can pass smoothly when it is pulled in the direction of the arrow
E
. After the best positioning has
been secured, fasten the two setscrews
❹
.
(Caution) If part
B
and
F
is damaged, this is the cause of thread breakage, hangnail of thread,
stain on thread, etc. Therefore, this part should be polished by the use of a buff or the
like. In particular, the rear side should be handled with care.
❶
❺
❶
❷
❸
❹
A
B
F
C
D
E
[LK-1903B-BS]
❶
❶
❷
A
B
C
❺
[LK-1900B-BS, 1900B-BF]