SINGER W4910 Euroflair - Manual (Page 16)

Ihread tension
Correct and incorrect thread tension
In order to easily understand the importance of correct
thread tension, you can try different thread tensions by
sewing on a scrap of fabric. Begin by using an excessively
loose tension, i.e. set the tension dial near “0”. Look at
the fabric and you will find that the lower thread lies
straight and the upper thread is drawn underneath the
fabric. If, however, you set the dial at the highest num­
ber, the opposite will occur, or the seam may pucker.
The thread tension is correct when the threads inter­
lock in the middle of both layers of fabric.
Please note that even the best quality thread may vary
m thickness. When sewing in fine fabrics, the knot may
sometimes be visible.
Always check that the thread tension is correct by first
sewing on a scrap of the same fabric, folded double, that
you intend to work with.