Check spring

[Shuttlebug]

I am still having problems with loops and double stitching on the bottom with thread breaking. I am beyond frustrated. I think I have it down to a big loop and then the thread snaps.. I am 1/3 of the way through a row. Half way into that 1/3 I hurt a little pop. I stopped and didn't see anything so I continued. Then I heard another pop and I stopped and the thread had broken. When I checked underneath I noticed a long thread at the first pop location. The thread had broken beneath the needle plate. It left about a three inche tail, but since it broke below the thread was still in the needle and kept sewing. The next one the thread made a loop and then broke and pulled out of the needle. I have spent all day checking for burrs, cleaning, adjusting, etc.

I saw somewhere that it could be the check spring. When I pull the thread through the needle the check spring seems to be working fine. I noticed a couple of times when I was testing tension that the check spring did not always come back up after the needle was out of the fabric until I moved the head a little. Is this normal or is there something wrong with my check spring?

[JenniferBernard]

The check spring sounds suspicious to me. Did you clean behind the tension disks? You can pull the disks out and run a rag behind and between them. Sometimes my thread gets a loop in it where it goes through the 3 guides right before the tension disks. The loop is very hard to see but I noticed it because my top tension was pulling really hard.

[jimerickson]

Your check spring (take up spring) is not working as it should.  If is isn't dragging on the head of the machine, it needs the tension on it increased.  To increase the tension, you need to take the tension assembly out of the machine, loosen the screw that holds the assembly together, rotate it clockwise about 1/4 turn, tighten the screw, and re-install the assembly in the machine.  When you put it back in the machine, make sure it sits out far enough that the take up spring never rubs on the machine head, and that the top of it's travel  is at about the 10:30 - 11:00 position.

 

You also need to check how deep the bobbin basket retainer finger (the black finger that keeps the bobbin basket from rotating) is set.  It should be in no more than 1/3 of the depth of the slot.  If it is deeper in than that, the thread loop can catch on it, which will cause the thread to break.  Good luck.  Jim