Testing and adjusting tension :---When there is perfect balance of
tension between the upper and lower threads , the stitches lock
or meet together in the middle of the thickness of the cloth .
when the upper tension is too tight , the spool thread lies
straight on the top of the fabric and the upper thread
appears like loops on the upper side of the cloth . If the
upper tension is to loose , the upper thread lies straight
on the upper side of the fabric and the upper thread
appears like loops on the underside .An easy method of recognising tension is to stitch diagonally
across a square of fabric folded on , and then to stretch the cloth firmly between your fingers
until one or both threads break . The thread which is broken is always the one with tighter
tension . If the tensions are balanced break together and require more force to break . To
increase or decrease upper tension , turn the screw on the tension regulator with the presser
foot down .In turning this screw remember that right is tight and left is loose . Usually there will be
numbers written on the tension dial . To increase tension you should turn towards the higher
numbers and to decrease , towards the lower numbers .
Avoid changing the lower tension unless you are sure that the
tension cannot be corrected completely by adjusting the top one alone .
The lower tension is adjusted by turning the small screw on the
bobbin case using a screw driver . usually the screw is turned to the
right to tighten and to the left to loosen . Make a very slight turn only
each time .