Maintenance; Adjusting The Needle-To-Hook Relation - JUKI LBH-1790 Instruction Manual

6. MAINTENANCE

Adjusting the needle-to-hook relation

WARNING :
To protect against possible personal injury due to abrupt start of the machine, be sure to start the
following work after turning the power off and ascertaining that the motor is at rest.
q
0.05 mm
q
e
A
B
C
w
Adjust the needle-to-hook relation when the needle
enters the center of the needle hole in the throat plate.
(1) Needle bar height
1) Bring down the needle bar to the lowest point.
2) Insert the part [1] A of timing gauge into the gap
between the bottom end of needle bar and throat
plate, where the bottom end of the needle bar
touches the top of the part[1] A of the timing gauge.
3) Loosen needle bar connection screw q, and adjust
the height of the needle bar.
(2) Set the needle to hook relation in the following
way :
1) Rotate the hand pulley in the correct direction until
the needle starts to go up from its lowest point.
2) Insert the part [2] B of the timing gauge into the
gap between the bottom end of the needle bar and
the throat plate, where the bottom end of the needle
bar touches the top of the part [2] B of the timing
gauge.
3) Loosen setscrew C of the hook sleeve, and align
blade point of the sewing hook with the center of
needle hole. Make adjustment so that a clearance
of approx. 0.05 mm is provided between the needle
and the blade point of the hook.
(3) Adjusting the bobbin case positioning stopper
Adjust with setscrew e so that the contact of the top
end of bobbin case positioning stopper q and the end
of inner hook w is 0 to 0.2 mm.
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