9
Pre-tension
When the main tensioner 2 and supplementary tensioner 3 are open the
needle thread must be under slight residual tension. This residual tension is
produced by the pre-tensioner 1.
The pre-tensioner 1 simultaneously affects the length of the end of the
se
vered needle thread (the starting thread for the next seam).
Basic setting:
– T
urn adjusting knob 4 until its front is flush with bolt 5.
Shorter starting thread:
– T
urn adjusting knob 4 clockwise.
Longer starting thread:
– T
urn adjusting knob 4 counter-clockwise.
Main tension
The main tensioner 2 should be set to the minimum possible tension.
The cross-over point of the thread should be in the centre of the material.
When using thin material, excessive thread tension can cause unwanted
ga
thering and thread breakage.
Adjust the main tensioner 2 so that an even stitch pattern is produced.
– I
ncrease tension - turn the adjusting knob clockwise.
– Decrease tension - turn the adjusting knob counter-clockwise.
Supplementary tension
The supplementary tensioner 3 can be switched in to effect a rapid change in
ne
edle-thread tension during operation e.g. with thickened seams.
Set the supplementary tensioner 3 to be lower than the main tensioner 2.
3.2.1 Function of the main thread tension and the supplementary thread tension in rela-
tion to the sewing foot lift for subclass 667-180312 and 667-180322
Button 1 (see chapter 3.15) on the machine's keypad can be used to activate
or deactivate the supplementa
ry thread tension at any time. Parameter F-299
must be set to "1" for this.
1 = Thread tensioner mechanically opened
0 = Thread tensioner me
chanically closed
If the supplementary thread tensioner is open, the status of the sewing foot lift does not change.
If the machine is turned off, the supplementary thread tension remains at its previously set state.
Sewing foot lift in the seam Sewing foot lift afterthread
trimming
Parameter
Setting
Main
th
read
tensioner
Supple-
mentary
th
read
tensioner
Main thread
te
nsioner
Supplemen-
tary thread
tensioner
F-196=0
F-196=1
F-196=2
F-196=3
0
1
0
1
0
1
0
1
0
0
1
1
0
0
1
1
