JUKI HZL-12Z User manual

Page 1/19
Original issue
Jun. 2012
Service Manual
HZL-12Z
Model
HZL-12Z

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Original issue
Jun. 2012
Service Manual
HZL-12Z
Model
TABLE OF CONTENTS
1. DISASSENBLING OUTER PARTS
2. FEED DOG HEIGHT
3. NEEDLE HEIGHT
4. HOOK OF NEEDLE THREADER
5. PRESSERFOOT HEIGT
6. NEEDLE POSITION, STRAIGHT STITCHING
7. NEEDLE SIDE MOTION
8. FEED DOG CLEARANCE TO NEEDLE PLATE
HOLE
9. NEEDLE TIMING TO SHUTTLE
10. NEEDLE CLEARANCE TO SHUTTLE
11. SHUTTLE SHAFT RATTLE
12. THREAD TENSION
13. ADJUSTING MOTOR BELT TENSION
14. ADJUSTING BUTTONHOLE PITCH BALANCE
*The parts in the pictures can be looked differently as what they are.

Page 3/19
Original issue
Jun. 2012
Service Manual
HZL-12Z
Model
１．DISASSENBLING OUTER PARTS (1)
(1) Removing a face cover
Take out 2 screws and remove a face cover.
(2) Removing a front cover
1. Take out 2 screws on a bottom surface.
2. Take out 4 screws of a back face.

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Original issue
Jun. 2012
Service Manual
HZL-12Z
Model
1. DISASSENBLING OUTER PARTS (2)
3. Take out 2 screws of a thread guide plate.
Loosen one of them and take off thread guide plate.
4. Take out 2 screws and take off a switch cover.
5. Remove front and back covers with a small screw driver.
Just loosen it.

Page 5/19
Original issue
Jun. 2012
Service Manual
HZL-12Z
Model
1. DISASSENBLING OUTER PARTS (3)
6. Extract a length control dial
7. Take off a side-on connection putting a hand in a hole of length control dial.
Take off a connection of a needle bar.
8. Take off a front cover.(Including a shuttle cover)
Disconnect this connector, and you can
take off a front cover.

Page 6/19
Original issue
Jun. 2012
Service Manual
HZL-12Z
Model
1. DISASSENBLING OUTER PARTS (4)
(3) Taking off a back cover.
1. Pull out a switch cover after taking out screws.
2. Pull out a back cover backwards and take it off.
*It is possible to do test sewing by attaching a thread guide plate(set).

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Original issue
Jun. 2012
Service Manual
HZL-12Z
Model
2. FEED DOG HEIGHT
〔Checking〕
1. Set the stitch length control at “maximum”.
2. Turning a hand wheel by hand, bring up feed dogs totheir top position.
3. Check if feed dog height is 0.89 – 1.09 mm from upper surface of a needle plate.
〔Adjustment〕
1. Under checking condition, while pushing a feel lifting lever(1) against a pin(3) of a
shuttle adjust lever(2), correct feed dog height by loosening 2 screws(4) and
turning an adjusting nut(5).
Lift a screw driver down(Clockwise direction) →Feed dogs become high
Lift a screw driver up(Anticlockwise direction) →Feed dogs become low
0.89 - 1.09mm
1
2
3
4
5

Page 8/19
Original issue
Jun. 2012
Service Manual
HZL-12Z
Model
3. NEEDLE HEIGHT
〔Checking〕
1. Set the zigzag width at “maximum”.
2. Turning a hand wheel by hand, bring a needle to its right hand and lowest position.
Then bring it to the center of a needle plate eyehole by turning the zigzag width
control dial.
3. Check if height of a needle tip is the same level as bottom surface of a gage.
* Bottom surface of a gage is 11.17mm from the centre of a shuttle.
* Top surface of a gage is 11.47mm from the centre of shuttle.
〔Adjustment〕
1. Remove a face cover.
2. Remove a thread guide plate(set).
3. Loosen a screw(2) of a needle bar clamp(1), and correct needle bar height by sliding
it up and / or down.After adjustment, tighten a screw(2) securely.(When tightening a
screw, a needle must be facing front.)
11.17 - 11.47mm
from center of a shuttle race
Needle position is center
and lowest
1
2

Page 9/19
Original issue
Jun. 2012
Service Manual
HZL-12Z
Model
4. HOOK OF NEEDLE THREADER
〔Checking and adjustment〕
Adjust position of a hook by using one of accessories, a small screw driver when
a hook is not aligned.

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Original issue
Jun. 2012
Service Manual
HZL-12Z
Model
5. PRESSER FOOT HEIGT
〔Checking〕
1. Raise a presser foot lifter.
2. Lower feed dogs below the upper surface of a needle plate by turning a hand
wheel.
3. Check if clearance between a presser foot and a needle plate is approx. 5.5 mm.
〔Adjustment〕
1. Raise a presser foot lifter.
2. Loosen a screw(2) of a presser bar bracket(1), and correct presser bar(3)
height by sliding it up or down.
3. After adjustment, tighten a screw(2) securely, keeping a presser foot in parallel
with feed dog direction.
5.5mm
1
2