Yes, there is such a thing! Have you ever been stitching along just fine, run out of thread, changed out your bobbin and suddenly found your tension going crazy?
Chances are you have found a bad bobbin in you collection.
Your tension should not change wildly whenever you change bobbins because if your top and bobbin thread stays the same, the stitch should remain consistent.
And who would even consider that a bobbin could be bad? I have never had this experience until quilting on the Juki and it's the only machine it's ever happened on.
So what do I mean by "bad"?
Well, with how much a bad bobbin effects tension, I assume that these bobbins weren't manufactured properly and may be slightly lopsided, making the bobbin spin unevenly in the case.
A good way to test is to load your bobbin into your machine and tug on it. The thread should glide freely and smoothly with no resistance. If it glitches up on you, try quilting a little on a sample square. If your tension is wildly out of whack, it's time to look for another bobbin.
I experienced this little annoyance today and unfortunately didn't realize it until I'd already stitched a very large part of this Dresden block.
See how part of the paisley designs are wanting to pull up and pucker? That's all due to this bad little bobbin.
On a regular quilt, I would have needed to rip all of this out because the stitches were so badly out of tension on the back.
So what do you do when you've identified a bad bobbin?
My first reaction was to throw that nasty little tension mangler in the trash, but then I reconsidered it and pulled him back out again.
It's not the bobbin's fault that he's gimpy and there are many uses other than putting it into your machine.
You can use bad bobbins to wind small amounts of thread for hand quilting, applique, or binding projects rather than take an entire spool of thread.
I really like to do this because I always use a magnetic pincushion and the metal bobbin case will stick to it and not get lost in the couch while I'm stitching.
You do need to know and be able to easily tell your bad bobbins from the good. Trust me, after this frustrating experience yesterday, this gimpy guy is never seeing inside of my machine again!
I labeled it as "bad" in big letters with a permanent magic marker on both sides.
I also went through and tested 3 other bobbins and found one to produce exceptionally smooth, beautiful stitches, so I labeled it with a "G" for good.
It's always good to know which bobbins produce your best stitches so when you're quilting with something finicky, like metallic thread, you can use a bobbin that won't make you tear your hair out.
So here's to weeding out all the gimpy, bad bobbins from your stash!
Let's go quilt!