I§]. Bight Adjustment - Singer 812U Instruction Manual

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Bight adjustment
Since bight depends on cloth trímrning width and the width of the throat plate's chain off fínger, cloth trímming
width must be changed at the same time in case of changing bight by more than I
mm.
1. To increase bight
•
(l)
Loosen movable knife holder set
screw
0,
move knife holder
@)
to right as much as necessary,
and retighten the set screw
0
securely.
(2) Loosen stationary knife holder
set screw f)) , and make the sta-
tionary knife pushed against the
movable knife by the stationary
knife holder spring.
(3) Tum the pulley until the rnov- .
able knife dose to its lowest
position and retighten the sta-
tionary knife holder set screw
f)).
2. To decrease bight
(l) Loosen the stationary knife hold-
er set screw
f)) ,
move knife holder
~
to left as much as necessary,
and temporari1y tighten the set
screw
f).
(2) Loosen the movable knífe holder
set screw
0,
move the knife hold-
er until the movable knife con-
tacts the stationary knife, and
retighten the set screw
0
secure-
ly.
•
.~
(3) Loosen temporari1y tightened set
screw
f),
make sure that the
stationary knife is pushed against
the movable knife, tum the pulley
until the movable knife close to
its lowest position, and retighten
set screw
f) .:
7.94mm
(Stationary knife)
, 1.5 mm
"--2mm
(Movable knife)
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In case of angle knife,
please unfasten screw
o
and do same ad-
justment.
Angle knife
Caution:
lf the knife cutting performance has dropped, sharpen
the movable knife or stationary knife as shown in right.
Ll]. Stitch length and
differenti~1
feed adjustment
The numerals on the scales ofmain feed arm
~
and differential feed arm
flI
indicate stitch length in millimeters,
but actual stitch length varies with the kind and thickness of the material and the differential feed.
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