SINGER W510 - Manual (Page 20)

TENSION
The top tension (Fig. 45) consists of discs
between which the upper thread passes.
The numbered tension dial regulates how
tightly the thread is being held. When
necessary, adjust the top tension dial in
relation to the red line, turning to a lower
number to loosen and to a higher number
to tighten the upper thread tension. The
top tension is engaged only when the
presser foot is down for sewing. Normal
top tension is usually about 5.
The bobbin thread tension is controlled
by a small screw on the side of the bobbin
case. (Fig. 46) This screw may be turned
with the small screw driver to the right
to tighten and to the left to loosen the
bobbin tension.
46
• Adjusting the Thread Tensions
The tensions may have to be adjusted for
47
CtJi Idin
: - ... .■.. Use a new
needle the correct size for the thread and
fabric being sewn. (See chart page 12)
It is best to test the tension on a scrap of
the fabric you are using for construction.
Always use a double thickness and always
sew on the bias when testing tensions.
The tensions are correct when the upper
thread and lower thread interlock be­
tween the two layers of fabric with the
loops not showing on top or bottom.
(Fig.47-A)
Adjust as follows:
1. If the seam is puckered both top and
bobbin tensions are too tight. Loosen
both tensions slightly.
2. If top thread lays on the fabric with
bottom thread looping over it, the top
tension is too tight.(Fig.47-B).Loosen
the top tension slightly.
3. If the bottom thread lays on the fabric
with the upper thread looping over it,
top tension is too loose.(Fig.47-C).
Tighten top tension slightly.
(B)
Top tension too tight
(C)
Top tension too loose
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