Cautions In Operation; Maintenance; Adjusting The Height Of The Needle Bar - JUKI LK-1900A Instruction Manual

6. Cautions in operation

(1) When the error indicator lamp lights up, be sure to check the cause of trouble and take a proper corrective
measure.
(2) Do not draw, by hand, the material being sewn during sewing. Doing so will cause the needle shift from
the correct position. If the needle moves from the correct position, press the
will return the needle to the normal origin.
(3) Do not turn OFF the power in a state that the needle is lowered. The presser comes down and the wiper
interferes with needle. As a result, there is a danger of needle breakage or the like.
Reference for the sewing speed to be applied
Sewn product / thread / needle
8-layered denim / Cotton thread #50 / DPx5 #16
8-layered woolen gabardine / Polyester filament #50 / DPx5 #14
8-layered denim / Cotton thread #20 / DPx17 #19
Overlapped sewing of 6 x 12-layered denim / Cotton thread #20 / DPx17 #19
Tricot + shoulder strap (3 + 1) layered section / Polyester spun #60 / DPx5 #11
* To prevent the thread breakage due to the needle heat, set the sewing speed referring to the above table
in accordance with the sewing conditions.
* For sewing the foundation or the like, lower the height of the needle bar to prevent the stitch skipping.
(Refer to the item "Adjusting the height of the needle bar")

[7] MAINTENANCE

1. Adjusting the height of the needle bar

WARNING :
Turn OFF the power before starting the work so as to prevent accidents caused by abrupt start of the
sewing machine.
Bring needle bar to the lowest position of its stroke. Loosen needle bar connection screw
that upper marker line
lower . For F type only, adjust the needle bar to the position where it is lowered by 0.8 mm to 1 mm from
the center of upper marker line
After the adjustment, make sure that there is no uneven torque.
When stitch skipping occurs in accordance with the sewing conditions, adjust the height of the needle
bar so as to lower it by 0.5 to 1 mm from the needle bar engraved line
: Engraved line
for DP x 5
: Engraved line
for DP x 17
is for H and W types only
engraved on the needle bar aligns with the bottom end of needle bar bushing,
engraved on the needle bar.
Head type / Sewing speed
S (Standard) / 3,000 rpm
S (Standard) / 2,300 rpm
H (Heavy-weight material)/3,000 rpm,
W (Double-capacity hook)/2,700 rpm
H (Heavy-weight material) / 2,500 rpm
F (Foundation) / 2,000 rpm
: Upper
engraved line
31
key two times. This
F type only.
and adjust so
.