—
—
8
14) Adjustment of forward/backward stitch length
(1) Loosen screw
①
on the right of the adjustment arm.
(2) Turn the eccentric shaft
②
and adjust.
(3) The forward stitch length will increase and the backward
length will decrease when the eccentric shaft
②
is turned
counterclockwise.
(4) The forward stitch length will decrease and the backward
length will increase when the eccentric shaft
②
is turned
clockwise.
15) Adjustment of knife engagement
a.
Position of fixed knife
(1) As a standard, the dimension between the fixed
knife's end and the needle center is 2.5mm.
(2) The standard relation of the knife (left) and fixed
knife is shown in the figure. As a standard, Di-
mension A is 0.3mm.
(3) When Dimension A is too large, the three piece
of threads will be cut, and can cause the needle
thread to come out from needle after trimming. If
too small, the thread may not be trimmed cor-
rectly.
(4) Adjust by adjusting the installation of the fixed
knife.
b. Knife engagement amount
(1) When the sewing machine is rotated while the
solenoid is activated, the knife (left) will be rotated by
the thread trimming cam.
As a standard, the knife engagement amount should be
1.5 to 2.0mm when the knife (left) moves the most.
(2)Adjust by adjusting the installation of the drive arm.
c. Adjustment of knife engagement pressure
(1)As a standard, the knife (left) and fixed knife should
start contacting at the position shown in the figure.
2) To adjust the engagement pressure, loosen the lock nut
②
and then adjust the adjustment screw
①
.
Summary of Contents for GC1998-MCDZ
Page 13: ...A ARM BED AND ITS ACCESSORIES 11...
Page 16: ...B NEEDLE BAR AND THREAD TAKE UP MECHANISM 14 14...
Page 18: ...C FEEDING AND FEED LIFTING MECHANISM 16 16...
Page 21: ...D STITCH REGULATOR MECHANISM 19 19...
Page 24: ...E KNIFE MECHANISM 22...
Page 26: ...F PRESSER FOOT MECHANISM 24 24...
Page 29: ...G THREAD TRIMMER MECHANISM 27 27...
Page 32: ...H TOUCH BACK AND DETECTOR MECHANISM 30 30...
Page 34: ...I MOTOR MECHANISM 32 32...
Page 36: ...J OIL LUBRICATION MECHANISM 34 34...
Page 38: ...K ACCESSORIES 36 36...
