Main motor jammed due to stuck bobbin threads

Thread nesting on the bottom (wrong) side is typically top thread not being pulled back by the take up lever due to insufficient (or zero) top thread tension.

If it is the bobbin thread, then test the bobbin thread tension. Most likely the thread has escaped the bobbin tensioner spring or the tensioner needs adjusted.

To be certain it is bobbin thread, as a test try using a contrasting color of top thread.

Follow manufacturers instructions to adjust bobbin tensioner spring.


See following video on testing tension

https://m.youtube.com/watch?v=YF7EOCvpHLg&feature=youtu.be

Sounds like thread or lint has got on the centre spindle of the hook. and jammed bobbin inside case. unclip race and remove hook and bobbin assembly. remove feed dogs and all tangled thread. machine should then be freed up

Is it forming a stitch at all? Do you have your needle set properly and are you certain it is the correct size. it sounds like the hook isn't catching the loop formed by the needle. If changing the needle doesn't help. it might be time for a clean and adjust.

try changing the needle
make sure the needle & thread & fabric are correct for each other
make sure ever thread guide is being used
try adjusting the top tension

This happened to me. I took apart the bobbin and there were no threads stuck. It moved freely, but the hand wheel was still stuck. So I checked the belt between the handwheel and the motor. I tugged on it (while the machine is off) and tugged on the belt to turn the handwheel. It took a couple tuggs to make the handwheel move, but once it started moving, it seemed to unfreeze. And I was back to normal. I can’t tell you what happened, but it’s fine now.

If the thread is getting jammed under the FABRIC then it means the TOP thread is threaded wrong. Just the opposite of what we think it should be. If the thread is looping on the TOP of your fabric it's the BOBBIN thread that's not threaded right. If it's a front loading bobbin, the thread should go over the top of the bobbin to the right before placing it in the bobbin case. Hope this helps!

That use to concern me too! I thought it signalled a problem, but my bobbin case has always been loose and that was not what was causing my thread and fabric jam. Usually what causes the jam is an incorrectly wound bobbin, wrong needle or old needle, old thread, or a slightly warped bobbin that is hard to see/detect. Change everything out--needle, thread, bobbin...this usually does the trick!

you might have a bent needle

I would take it to a mechanic.

Remove the bobbin, bobbin case as well as the shuttle hook. There are black pins/holders that hold the shuttle hook. After you remove these 3 components, make sure there are no thread stuck in between the 2 hook pieces as well as the bobbin shaft. Most of them time, there are either fabric or thread stuck. If not, make sure the needle is not hitting the feed dog or the hook.