Standard Adjustment; Height Of The Needle Bar; Positioning The Needle And The Looper - JUKI MB-373 Manual

2. STANDARD ADJUSTMENT

(1) Height of the needle bar

The upper engraved line should be aligned with the bottom of lower bushing 3 when the needle bar is
at its lowest position.
Standard needle for MB-373 : TQ x 7
Standard needle for MB-377 : TQ x 1

(2) Positioning the needle and the looper

1) Looper timing
When the needle bar is ascending from its lowest
position and the lower engraved line on the needle
bar is aligned with the bottom of the lower bushing,
the looper's blade point should coincide with the
center of the needle. (When the needle bar is
ascending.)
2) Clearance between the needle and looper
The clearance is 0.01 to 0.1 mm when the looper's
blade point coincides with the center of the needle.
3) Clearance between the needle guide and needle
The clearance between needle guide 6 and
needle is 0 to 0.1 mm when the needle bar is at its
lowest position.
Standard Adjustment
3
Engraved line
Height of the needle bar
Clearance between needle and looper
Clearance between needle and looper
2
− −
Looper timing
Lower bushing
Engraved line
Looper's blade
point coincides
with center of
needle.
0.01 to 0.1 mm
Looper's blade point
6
8
0 to 0.1 mm
For TQ x 1
For TQ x 7