Feed Timing; Needle-To-Hook Timing - JUKI HZL-30Z Service Manual

4-7 Feed timing

After checking the feed dog height and needle bar height, perform this adjustment.
The feed timing will affect the tightness of the needle thread.
How to adjust
* Adjust so that the tip of the needle aligns with the top surface of the throat plate when the feed dog meets with the top
surface of the throat plate. The tolerance is within the range of the tip of the needle to the lower end of the needle hole.

4-8 Needle-to-hook timing

Remove the throat plate, base plate, free arm bottom cover.
How to check
How to adjust
Caution
1. Attach HA x 1 #14 needle.
2. Loosen two screws in the main shaft pulley.
3. Turn the hand wheel and lower the needle bar to align the
tip of the needle with the top surface of the throat plate.
4. Turn the hook driving shaft and move the hook driving
shaft in the direction of rotation so that the top end of
the feed dog aligns with the top surface of the throat
plate in the direction where the feed dog comes down
from the highest point.
5. Temporarily tighten the screws in the main shaft pulley
and check again.
6. After performing this adjustment, check also "Needle-to-hook timing".
1. First, make sure that the needle entry position and the height of the needle bar have
been properly adjusted.
2. Select the straight stitch (left needle position).
3. Then turn the hand wheel by hand to bring the needle bar to the lowest point of its
stroke.
4. Further, gradually raise the needle bar by hand and stop it at point C where the
center of the needle aligns with the top end of the blade of the hook.
5. At this time, make sure that dimension D from the top end of the blade of the hook to
the upper end of the needle eyelet is 1.06 to 1.26 mm. When the dimension is not
proper, perform the adjustment below.
1. Loosen the setscrew in the hook drive gear which is hidden as observed from the
bottom side of the sewing machine when the center of the needle aligns with the top
end of the blade of the hook.
2. Loosen the setscrew in the hook drive gear and move it in the direction of rotation so
that dimension D from the top end of the blade of the hook to the upper end of the
needle eyelet is 1.06 to 1.26 mm when raising (3.27 mm) the needle bar from the
lowest point of its stroke.
At this time, the backlash with the gear on the hook side changes according to the
position of the hook drive gear in the direction of the hook driving shaft. Adjust the
hook drive gear by temporarily tightening the setscrew while taking care of both
directions of rotation and shaft.
Backlash is small.
Backlash is large.
3. After confirming the adjustment, securely tighten both of the setscrews.
• DimeAfter adjusting the hook, wipe out the race face of the hook or the bobbin case
with alcohol since there may be a case where dirt, oil, grease, etc. stick on the race
face of the hook or the bobbin case. Otherwise, running noise, noise from the bobbin
case, noise of slip-off of the thread, etc. will happen.
D
1.06
to
1.26 mm
Torque is large, and rumbling noise occurs.
Clattering noise and skipped stitch occurs.
C
Screw No.1
Screw No.2
3.27 mm
-11- -11- -11- -11- -11-
Upper side in the rear
Main shaft pulley
Outer hook
Backlash
Small
Front side
Hook
drive gear
Large