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Adjustment Procedure
4) Adjusting the knife unit
[1] For checking the knife unit
1. Check to make sure that the power switch is in the OFF state.
Remove the gauge (presser foot, throat plate and feed dog) from
around the needle.
2. In the standby state of loop spreading knife ❶, the distance from
center of needle A to the tip of loop spreading knife ❶ is 5.5 to
6.5 mm. (Refer to Fig.1-a)
3. At the time of 2, the thread trimming drive arm ❹ gets contact
with the screw ❸.
When there is a gap, loosen the screw ❺ and make the thread
trimming drive arm ❹ keep in contact with the screw ❸ to tighten
the screw ❺. (Refer to the Fig. 1-b.)
4. The purpose of adjustment of the aligning position of loop
spreading knife ❶ and thread trimming knife ❷ (far end of the
hole in loop spreading knife ❶ and the tip of thread trimming
knife ❷) is to align the aforementioned aligning position with
center of needle A. (Refer to Fig.2)
* There is seldom an actual margin of adjustment because it is
used for the creak of the Phillips -head screw.
5. The amount of engagement between loop spreading knife ❶ and
thread trimming knife ❷ is S type : 2.0 ± 2.5 mm, H type : 2.5 to
3.0 mm as measured from center of needle A. (Refer to Fig.3)
Results of Improper Adjustment
○ Be aware that, if the distance be-
tween loop spreading knife ❶ and
center of needle A is reduced,
thread loop is likely to interfere with
loop spreading knife ❶.
* Refer to "3.-(11)-4)-[2]. Adjustment
of the knife unit" for how to adjust
it.
○ Be aware that, if the aligning posi-
tion of the loop spreading knife and
the thread trimming knife does not
align with center of needle A, the
length of thread remaining on the
material after thread trimming will
be longer.
○ Be aware that, if the amount of
engagement between them is in-
sufficient, faulty thread trimming
can occur.
Refer to "3.-(11)-4)-[2]. Adjustment
of the knife unit" for how to adjust
it.
○ The needle thread may be trimmed
excessively short in the case thread
which is likely to cause unstable
thread loop formation is used or
thread trimming is carried out at a
position where there is no material.
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