Adjusting The Needle-Thread Tension; Opening The Needle-Thread Tensioner - Duerkopp Adler 69 Operating Instructions Manual

5.3

Adjusting the needle-thread tension

Pre-tensioning mechanism (subclass 69-FA-373)
On subclass 69-FA-373 the needle thread needs to be under residual tension for the
thread cutter to function reliably when the main tensioner 2 is open.
This residual tension is created by the pre-tensioning mechanism 1.
The pre-tensioning mechanism 1 also determines the length of the needle-thread end
after the thread has been clipped.
The pre-tension 1 should be set lower than the main tension 2.
–
Adjust pre-tensioning mechanism 1 by turning the knurled nut.
–
After major changes to preliminary tension 1 the main tension 2 should also be
adjusted accordingly.
Main tension
The main tension 2 should be set as low as possible.
The looping of the threads must be in the centre of the material (see fig. a).
With thin material excessive thread tension can cause unwanted gathering and thread
breakage.
–
Adjust the main tensioner 2 so that the stitches are uniform.
5.4

Opening the needle-thread tensioner

Automatic
The main tensioner 2 is opened automatically:
–
when the thread is severed (subclass 69-FA-373).
–
when the foot is raised (pedal 1 position backwards)
Manual
The main tensioner 2 is opened manually:
–
when the release lever 3 is pressed towards the arm.
The main tensioner 2 remains open for as long as pressure is maintained on the
release lever 3.
–
when the sewing feet are raised mechanically with the knee lever (see chapter 5.9).
–
when the sewing feet are locked in the raised position (see chapter 5.10).
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