Turn the dial back to the position your manual calls normal, which is around 4 on most machines, and treat the bobbin separately. On a computerised machine there is usually a reset in the settings menu that returns every stitch to its factory value.
Why this comes up. Tension faults are usually threading faults, and the standard response is to turn the dial. After a bad session the machine may sit several numbers away from where it started, and now genuinely misbehaves.
The order to reset in.
One: put the top dial back to normal. If your dial carries no marking, the manual states the position.
Two: leave the bobbin alone unless you moved it. The small screw on the bobbin case is set at the factory and rarely needs touching. If you did move it, the traditional check is the drop test — a full bobbin in its case should slip a few centimetres when the thread is jerked gently, and not fall freely.
Three: rethread completely with the foot up, fit a new needle, and clean the race.
Four: sew a test line on doubled scrap with contrasting threads.
Then mark your normal position. A dot of correction fluid or a small mark against the dial makes it obvious at a glance, and it stops the drift starting again.
If normal is wrong on a machine that has never been serviced, the fault is usually lint packed between the tension discs.
Questions people actually ask
I have lost the manual.
Most manufacturers publish manuals for current and older machines. Failing that, set the dial to the middle of its range and test from there.
How do I clean between the tension discs?
Raise the presser foot to open them, then run a folded strip of thin fabric or a length of thread through the gap. Never use a metal tool.
Last reviewed 2026-08-11