I've been following this newsgroup for a while, but have never found anything on this problem. Am I the only one, or have others run into it?
I have a Brother PC-8500, which I like very much. I wind my own bobbins, with Brother bobbin thread.
I was buying compatible bobbins (not exactly the same), but I found, as I wound them, they would sometimes split. You could hear slight cracking noises as the bobbins were wound. I overlooked it at first (the bobbin was more warped than split) and had some tension issues until I realized the bobbin was cracked and uneven.
So, I bought a bunch of true Brother bobbins on eBay. They seemed stronger, but again, last night, while winding a bobbin, I heard the slight cracking noise, and, sure enough, the bobbin popped wide open, into two parts.
I don't think the bobbin tension is too high, because, when the bobbins _don't_ crack, I get excellent results on the stitch-outs. But I can't believe bobbins are meant to have that short a life. Has anyone else experienced this?