Beisler 739-23-1 Manual - Manual (Page 13)

2.5 Adjustment of needle thread tension
Main tension
The main tension 1 must be set to the lowest possible value.
The looping of the threads must be positioned at the centre of the
sewing material.
In thin materials, excessive thread tensions can result in gathering or
breaking threads.
The main tension 1 must be adjusted in such a way that a regular stitch
pattern is achieved.
–
To increase tension
Turn knurled nut clockwise
– To reduce tension
Turn knurled nut anticlockwise
2.6 Opening of needle thread tensioner
Automatic
Upon cutting of the thread, the needle thread is automatically lifted.
1-13