Adjust the tension of the upper thread and bobbin thread for better balance when sewing.Note: If a tension gauge is used, the correct bobbin tension is 20-25g. If the bobbin does not fall, loosen the screw until the bobbin is just barely holding its own weight. If the bobbin falls to the ground, it is too loose and you will need to tighten the screw (on the tension spring). The ideal tension should be when the bobbin does not move, or is very slow releasing thread. Hold the bobbin by the thread hanging out of the case to check the tension.If bobbin case has a middle thread guide or pigtail, do not thread through at this time. Pull bobbin from under hole of tension spring.Slide the thread under the tension spring.
#Brother db2 b790 3 manual install#
Install a new bobbin of correct size into bobbin case.This is to ensure consistency once proper tension is set. Make sure that the bobbin case and spring are clean before beginning this procedure.If too much thread shows, turn dial clockwise. If too much shows, turn dial counter-clockwise. If using sew outs to check for tension, ensure that there is 1/3 bobbin showing in the back of the sew out.Note: This method is an alternate to using a thread-tension gauge, or doing sew outs to test tension.It is meant to get the upper thread relatively close to the correct tension(provided that the Trim Tail Length setting on the machine is still at its standard or default setting). Then re-evaluate whether to tighten or loosen more. A1/2 turn at a time should be used until the next trim takes place. If the thread is too short, loosen the rotary-tension knob by turning it counter-clockwise. (The thread extends 70mm past the needle hole.) If the thread tail length is too long, tighten the rotary tension knob by turning it clockwise. The lower or rotary tension knob should be set so that after the machine trims (and before it color-changes off of the needle), the thread-tail length should be even with (or 3/8" below) the bottom of the presser foot.This is the standard adjustment and should remain in this position. The pretension knob, or top knob, should be screwed down until the top of the adjustment knob is even with the bottom of the slot (on the tension-knob stud).Insert the bobbin into these durable metal bobbin cases.