Operating instructions

4.10 Thread tension
The machine head has been set in the factory for sewing buttonholes
with flat bartacks and with raised lips.
Pre-tension
The pre-tension
4
is always active. It serves for stabilising the needle
thread. It should be set to the minimum value ( 5-10 g ). The
pre-tension
4
has scarcely any influence on the seam pattern.
Main tension
The main tension
5
is active when sewing both buttonhole lips. But the
main tension
5
it is out of action when bartacking and when cutting the
threads.
Bartack tension
The bartack tension
6
is opened only when cutting the threads. It is
remains closed during the entire remaining sewing process.
Buttonhole lip tension
The buttonhole lip tension is produced jointly by the main tension
5
and by the bartacking tension
6.
About 1/3 of the buttonhole lip tension
should be produced by the bartacking tension
6
.
Adjustment
–
Thread the needle thread so that it does not pass through the main
tension
5
.
–
Start the sewing process.
4
5
6
16