Needle-To-Hook Relationship; Height Of The Feed Dog - JUKI DDL-900B Instruction Manual

22. Needle-to-hook relationship

WARNING :
Be sure to turn the power OFF before the following work in order to prevent personal injury due to
unintentional starting of the sewing machine.
❶
❸
❹
B
A
❷
Dimension F (mm)
DDL-900B
If the clearance between the blade point
of hook and the needle is smaller than the
specified value, the blade point of hook
will be damaged. If the clearance is larger,
stitch skipping will result.

23. Height of the feed dog

WARNING :
Be sure to turn the power OFF before the following work in order to prevent personal injury due to
unintentional starting of the sewing machine.
❶
C
A
D
B
F
E
❺
0.04 to 0.10
❷
0.75 to 0.85 mm (S type)
1.15 to 1.25 mm (H type)
Adjust the timing between the needle and
the hook as follows :
1) Turn the handwheel to bright the needle bar
down to the lowest point of its stroke, and loosen
setscrew ❶.
Adjusting the needle bar height.
2) [For a DB/DP needles]
Align marker line A on the needle bar ❷ with the
bottom end of the needle bar lower bushing ❸,
then tighten clamping screw ❶ of the needle bar
connection.
[For a DA needle]
Align marker line C on the needle bar ❷ with the
bottom end of the needle bar lower bushing ❸,
then tighten clamping screw ❶ of the needle bar
connection.
Adjusting position of the hook ❺.
3) [For a DB/DP needles]
Loosen three setscrews of the hook, turn the
handwheel and align marker line B on ascending
the needle bar ❷ with bottom end of the needle
bar lower bushing ❸.
[For a DA needle]
Loosen three setscrews of the hook, turn the
handwheel and align marker line D on ascending
the needle bar ❷ with bottom end of the needle
bar lower bushing ❸.
4) After making the adjustments mentioned in the
above steps, align the blade point E of hook ❺
with the center of needle ❹. Provide a clearance
of dimension F (reference value) between the
needle ❹ and the hook ❺, then securely tighten
three setscrews of the hook.
To adjust the height of the feed dog :
1) Loosen screw ❷ of crank ❶.
2) Move the feed bar up or down to make adjust-
ment.
3) Securely tighten screw ❷.
If the clamping pressure is insufficient,
the motion of the forked portion becomes
heavy.
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