JUKI MB-373 Manual page 19

Adjustment Procedures
™ Make adjustment after tilting the machine head by loosening
two nuts 3 and moving connecting screw 4 back and forth.
Loosen nuts 3 so that thread trimming connecting joint 5
becomes almost horizontal.
™ If the above distance is too large, the timing of the thread
trimming will be delayed, and excessively long thread will
remain on the wrong side of a fabric.
On the contrary, if the distance is too small, thread will be
trimmed too early, often resulting in poor tightness of the
final stitch (easy break), trimming two threads together due
to failure of thread separation, or failure to trim thread.
™ Make adjustment by bending thread separating claw 1.
™ Install button clamp lifting rod 1, spring 2, washer 3,
cushion 4, and washer 5 in the numerical sequence as
shown in the figure on the previous page.
™ After confirming that the stop motion is set fully, bring the
jaw of the machine arm to a close contact with the top surface
of washer 5, leaving no play. Then, firmly tighten screw 6.
3
4
5
19
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Results of Improper Adjustment
™ If the adjustment value is small (10
mm or less), the thread separating
claw will come in contact with the
counter knife or the yoke slide insert
due to overrunning of the moving
knife at the time of stop motion
resulting in breakage of the thread
separating claw.
™ If the adjustment value is large (15
mm or more), the thread separating
claw will come in contact with the
yoke slide insert during machine
running resulting in breakage of the
thread separating claw.
(Caution)
The thread trimming connecting
mechanism is reset by the pressure
springs of the button clamp jaw
levers. Accordingly, the thread
trimming connecting mechanism
may not be reset when the pressure
springs are disengaged. Do not
operate the machine when making
adjustment with the pressure
springs disengaged.
™ If the thread separating claw is too
high, the claw may fail to separate
the thread on the needle from that
on a fabric. As a result, thread may
not be trimmed, or the both threads
are trimmed together, causing
thread slippage from the needle in
the subsequent stitching start.