JUKI MO-6800S Series Engineer's Manual page 27

Adjustment procedures
1) For 1-needle or 2-needle overlock machine
1. Adjust needle guard ❸ with setscrew ❺ of the needle guard so
that it lightly comes in contact with the needle ❷ (bend needle ❷
by 0 to 0.05 mm) when the needle ❷ is at the lowest point of its
stroke.
2. When the needle ❷ is at the lowest point of its stroke, loosen
setscrews ❻ of the needle guard and move needle guard ❹ to
adjust the clearance provided between needle guard ❹ and the
needle ❷ should be 0.1 to 0.2 mm.
2) For safely stitch machine
1. Loosen setscrews  of the needle guard, and adjust the clear-
ance provided between needle guard ❾ and the needle ❷ so
that it lightly comes in contact with the needle ❷ (bend needle ❷
by 0 to 0.05 mm).
2. Adjust the clearance provided between needle guard  and the
needle ❷ to 0.1 to 0.2 mm with setscrews ❽ .
Results of Improper adjustment
Excessively close contact
o
between the needle guard ❸
and the needles ❷ will lead to
needle bend or stitch skipping.
Excessive clearance between
o
the needle guard ❸ and the
needle ❷ will cause the blade
point of looper to come in con-
tact with the needles ❷ , leading
to needle or blade point break-
age, or other troubles.
Excessive clearance between
o
the needle guard ❹ and the nee-
dle ❷ will cause stitch skipping
due to needle shake. On the
contrary, insufficient clearance
will cause the needle guards to
catch the needles ❷ between
them, leading to wear on the
needle guards and scratches on
the needles.
If the clearance between the
o
needle guard ❾ and the needles
is too large, the blade point of
double chain looper will come
in contact with the needles ❷ ,
causing the breakage of the
needles, causing the breakage
of the needles or blade point of
looper.
No clearance left between them
will cause them to come in
excessively close contact with
each other, and wear on the
needle guard and scratches on
the needles will occur.
Excessive clearance left be-
o
tween the needle guard  and
the needles will cause stitch
skipping due to needle shake,
and insufficient clearance will
cause the needle guards to
catch the needles between
them, leading to wear on the
needle guards and scratches on
the needles.
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