Adjustment Of The Upper Thread Tension; Change Of The Hook Bobbin, Threading And Setting Of The Bottom Thread Tension - Duerkopp Adler 527 Instruction Manual

6.4 Adjustment of the upper thread tension

(Fig. 1, 2, 5)
The tension of the upper and that of the bottom thread must be
mutually adjusted in such a way, so that the stitch locking is being
done in the middle of the sewn material (Fig. 5). The tension of the
upper thread is to be adjusted by turning a bit the nut of the tensioner
(M, Fig. 2). In turning the nut to the right (in the clockwise direction),
we increase the tension of the upper thread, in turning it in the
opposite direction, we reduce the tension of the thread.
When the machine is provided with a thread cutter of thread (version
-105), its correct function is to be given major attention in adjusting
correctly the thread tension. It is necessary to set correctly the
auxiliary tensioner (L, Fig. 1) the function of which influences the
length of the upper thread end which is projecting from the needle
eye after having cut the thread. When correctly setting of the tensio-
ner, the quality of the initial stitches is good and no unthreading of
the thread out from the needle occurs. When increasing the adjusted
tension of the auxiliary tensioner this end is shorter (the seam
starts are of better quality), but there is an increased danger that this length will not be sufficient for starting further stitching,
when the thread would leave the needle eye. In the opposite case, namely with a too small tension, the given ends are uselessly
too long which worsens the quality of the stitch start on the rear side of the sewn material.
6.5 Change of the hook bobbin, threading and setting of the bottom thread tension (Fig. 6, 7)
Caution!
Do not start the machine before placing the hook covers in their working (protective) position.
Before changing the bobbin in the hook, switch off the main switch and put your feet off the pedals on the stand to
avoid the machine start by treading the pedal.
Using the flap (F), remove the bobbin case from the hook.
Put the full bobbin (A) into the bobbin case (B) and guide the thread through the groove (C) under the braking spring (D) and then
into the hole (E).
Let free about 5 – 6 cm of the thread end. It is recommended to turn the bobbin in the arrow direction when pulling the thread.
After having inserted the bobbin case into the hook be sure in assuring this by the flap (F). As usual, by means of the the upper
thread, we thread the bottom thread above the throat plate.
The tension of the bootom thread is regulated by a screw (G). In turning it in the (+) direction, the pulling power increases, in the
(-) direction it is reduced. When the tension of the bottom thread is correctly adjusted, then a good stitch laying is generally being
ensured by the respective adjustment of the upper thread tension by means of the tensioner nut.
F
Fig. 6
4
D
C
G
D
C
Correct adjustment
of the tension of both
threads
Incorrect adjustment
Incorrect adjustment
Fig. 5
+
-
B
A
E
F
Fig. 7