Mysterious problem with newly wound bobbin in 440QE
 

I had a strange problem with my Bernina 440QE today. I think I've solved it, but I'm still not sure I understand it. I was sewing along when my bobbin ran out of thread. I decided it was a good time to clean and oil the machine, so I did, and then I wound the same bobbin I had been using, with the same type of thread. I replaced the bobbin case into the machine and used the threaded needle to pull up the bobbin thread. But the bobbin thread wouldn't move any further! I tried several times fiddling with the bobbin and bobbin case. I verified that the thread would move smoothly out of the bobbin when it was inserted into the bobbin case before it was put in the machine, but seemed stuck after the bobbin case was inserted into the machine. I finally decided maybe that bobbin was somehow damaged (though I couldn't see how that could be possible). I tried another bobbin that I had wound previously, and it worked just fine. So I rewound the thread from the first bobbin onto another bobbin, and again had the same problem as before. About then I noticed that the newly wound bobbins seemed to be fuller and more tightly wound than the old one. I've wound bobbin this full often in the past without any issues, but I wound another bobbin, only about 1/3 as full, and that bobbin is working just fine. Now I don't know for sure what the problem was. Did the bobbin winder suddenly change how it winds bobbins? Will there be problems again if I wind a fuller bobbin? I guess time will tell. Has anyone else had a similar problem?

That's bizarre! This doesn't address your issue but is related: the last time I had my Bernina serviced, I noticed that the bobbin winder came back set so it doesn't fill the bobbins as full as it did previously, so there must be some way to internally set to specifications when to stop winding. I think over time the bobbin winder had gradually worked to the point it was filling the bobbins too full.

Interesting. I guess it's possible that after time and use the sensors would let the bobbin fill overly full. Let us know what happens, Dunster.

I don't know about this model of Bernina but have you tried a prewound bobbin? They are wound tight and full according to bobbin size. My older Bernina stitches better with pre wound bobbins.

There's a tiny hole near your bobbin winder, with a screw inside it. That's where we adjust how full the bobbin gets.

Thank you, Annette. That's good to know. I'd never heard that before and it's something I could do myself

Yes, I thank you too. I usually stop the bobbin from winding before it's very full. I know that my longarm has a problem with bobbins that are too full, and I've adjusted the standalone bobbin winder that I use for the large bobbins so that it stops in time. I didn't realize that I could make a similar adjustment on the Bernina.

Learn something new every day! Thanks for the info Annette.

Wonder if this will also work on Singer Heavy Duty machines. Will have to get it adjusted after the move as it now "clicks". Don't know why but I immediately stopped sewing and pulled the plug so I don't ruin it. I'm still working on my projects for the Children's Hospital just not yet sewing the quilts tight--basting everything by hand.

Berninas can’’t use pre-wound bobbins. The bobbins are just enough different to prohibit it. The possible exception are the quilting machines. I think at least one of them uses standard M bobbins.