My thread keeps breaking on my Bernina 800dl serger
Is the thread aerial raised up ensuring a good thread flow?
Which thread is breaking, needle or looper? If you can establish which thread is breaking, then check that tension dial, turn it to zero and clean between the tension discs by sawing a selvage edge of cotton fabric offcut between the two discs to remove any fibres, dirt or debris.
Now turn all dials to zero, unthread the needles, and pull on each thread, feeling if there is any resistance. If there is, check back through the thread path and find where the thread is catching.
Serger threads flow very fast and the thread path can't be compromised or the thread snagged.
Check the thread path from the cone to the sewing foot, and ensure that the thread is not catching on something, or getting caught around the cone, cone holder or aerial somewhere in the path. Look at the thread cone, has the thread feeding off got looped around itself somewhere? Open up front of the serger and look at the thread going through the loopers, is something misthreaded here, sometimes there is a part that slides on a looper to make threading easier, just check it is all threaded up correctly. There should be a threading diagram inside the serger cover usually showing the paths.
Rethread the needle(s) and pull all the threads under the pressure foot, lower the foot, turn tensions back to 5, then chain off and test sew.
If no joy after trying all this, I'd take it for a ride in the car to the shop.
Apr 14, 2011 |