dunster

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?