1. If the dimensions of 0.3 x 8mm are not secured, retouching is re-
quired with the aid of an oil stone.
1) Stroke adjustment
Loosen the set screw
, and turn the thread tension assembly
.
Turning it clockwise increases the movable distance and thread draw-
ing amount.
2) Adjustment of thread take-up spring tension
Turn the thread tension post
using a thin driver with the set screw
tightened to adjust the thread take-up spring
tension. Turning
it clockwise increases the thread take-up spring
tension, and turn
it counterclockwise decreases the tension.
(Caution) Set the stroke of the thread take-up spring
shorter
for thin threads with thread number #50 or higher.
o If the stroke of the thread take-up
spring is larger than the specified
value:
Length of remaining needle
thread is shortened, causing the
needle thread to slip off the needle
at the sewing start.
o If the stroke of the thread take-up
spring is smaller than the speci-
fied value:
Needle thread breakage will oc-
cur at the time of thread trimming
when using a thin thread.
(Caution)
If the thread take-up spring
interferes with the L-shaped
thread guide
, the thread take-
up spring
may fail to return to
the initial position before thread
trimming, and the length of re-
maining needle thread may be
short. If such a trouble occurs,
bend the section
C
C
C
C
C
of the thread
take-up spring
to widen the
clearance
B
B
B
B
B
.
– 60 –
Adjustment Procedures
Results of Improper Adjustment
Adjustment Procedures
Results of Improper Adjustment
Part No.
Name of part
Remarks
0.8
14103253
Shuttle race ring A
Optional
1.3
14103352
Shuttle race ring B
Standard
1.7
14103659
Shuttle race ring C
Optional
1.9
B1817210DAD
Shuttle race ring D
Optional
Dimension A
(mm)
