Adjusting The Looper; Adjusting The Height Of The Needle - JUKI MF-7900 Instruction Manual

6. adjusting the looper

WarNING :
to protect against possible personal injury due to abrupt start of the machine, be sure to start the fol-
lowing work after turning the power off and ascertaining that the motor is at rest.
1
a
[Lateral position]
The relaton between clearance a between looper 1
and the center of rght-hand needle and the needle
gauge s as shown n the table.
2-needle
Needle gauge Return amount a Needle gauge Return amount a
3.2 4.3
4.0 3.9
4.8 3.5
5.6 3.
6.4 2.7
Loosen clamp screw 2 and laterally adjust looper
holder 3 n accordance wth the table.

7. adjusting the height of the needle

WarNING :
to protect against possible personal injury due to abrupt start of the machine, be sure to start the fol-
lowing work after turning the power off and ascertaining that the motor is at rest.
B
1
a
2
) Equally adjust clearance a between needles 1 and
needle holes 2 n the throat plate.
2) Adjust the needle bar heght so that the top end of
the left-hand needle eyelet algns wth the bottom
end of looper when the looper travels from the
extreme rght poston to the left untl the top end B
of the looper protrudes from the left end of the left-
hand needle by approxmately  to .2 mm. Then,
remove rubber cap 4 from the face plate, and
tghten needle bar connecton setscrew 3 .
6
1
unit : mm
3-needle
5.6 3.
6.4 2.7
c
– 8 –
2
5
3
[Longitudinal position]
Adjust so that the clearance between blade pont 5 of
the looper and medum needle 4 s 0 to 0.05 mm when
the top end of the looper comes from the extreme rght
poston to the center of the medum needle. After the
adjustment, tghten clamp screw 2 to fix the looper.
* The blade pont of the looper comes n contact wth
the rght-hand needle when rear needle guard 6
does not work. So, be careful.
4
A
Reference : Heght from the top surface of the throat
plate A to the top end of left-hand needle,
c when the needle s n the hgher dead
pont s as shown n the table.
2-needle
Needle gauge Heght of left-
hand needle, c
3.2 8.9
4.0 8.6
4.8
8.
5.6 7.8
6.4 7.3
4
3
unit : mm
3-needle
Needle gauge Heght of left-
hand needle, c
5.6 7.8
6.4 7.3