I am trying to sew a pair of jeans. I threaded the thread on top right and i believe that the bobbin is threaded correctly, but when i start sewing, the thread in the bobbin compartment gets jammed and tangles up.

Your thread may be too large for the machine to use. Try using the highest setting on the tension.

Between 3 and 4

The top thread breaks
1. the needle thread is not threaded properly
2. The needle thread tension is to tight
3. The needle is bent or blunt
4. The needle is incorrectly inserted
5. The needle thread & the bobbin thread are not set under the presser foot when starting to sew
6. the threads were not drawn to the rear after sewing
7. The thread is either to heavy or to fine for the needle
8. Try a different spool or cone of thread

Bobbin thread breaks
1. There is a right way & wrong way to insert the bobbin in the case --when you insert the bobbin in if it doesn't stitch correctly turn the bobbin over see if that helps or bobbin case is not inserted correctly
2. Lint has collected in the bobbin holder
3. The bobbin is damaged & doesn't turn smoothly
4. Lower thread tension is two tight

The top thread breaks

1. the needle thread is not threaded properly

2. The needle thread tension is to tight

3. The needle is bent or blunt

4. The needle is incorrectly inserted

5. The needle thread & the bobbin thread are not set under the presser foot when starting to sew

6. the threads were not drawn to the rear after sewing

7. The thread is either to heavy or to fine for the needle

8. Try a different spool or cone of thread


Bobbin thread breaks


1. There is a right way & wrong way to insert the bobbin in the case --when you insert the bobbin in if it doesn't stitch correctly turn the bobbin over see if that helps or bobbin case is not inserted correctly


2. Lint has collected in the bobbin holder


3. The bobbin is damaged & doesn't turn smoothly


4. Lower thread tension is two tight

if the sewing machine has a top loading bobbin, you may have to have the sewing machine checked to see if there is something wrong with the bobbin case or the hook and hook race.
I suggest try a new needle--one for the fabric being sewed
also try another bobbin
rethread the sewing machine top and bobbin, using every thread guide.

are you using a denim needle for sewing jeans?
where is the thread getting caught up at?
make sure the bobbin is turned the right direction in the bobbin case

try changing the needle
rethread the machine top & bobbin
make sure to use every thread guide
make sure the bobbin is turned the right direction in the bobbin case
if the bobbin is turned the wrong way in the bobbin case it will
cause sewing problems,,( believe me,,)
make sure the top thread has not come off the thread take up lever

first let's deal with the needle becoming unthreaded, Keeping the needle threaded is easy, always keep thread tails of 3 to 6 inches on the top thread & bobbin at all times, & make sure the thread tail are pulled behind the needle before you start to sew,, this will ensure that the thread will not come out of the needle when you start to sew.

you mention the fabric is thin,, do you have a needle that's right for the fabric your sewing?
thin fabric needs a different needle than blue jeans fabric, check your top tension & see what the setting is on, usually 3 to 5 is good.

when the needle & thread are right for the fabric then the sewing is good.

also clean under the needle plate & bobbin area for loose threads or lint

also it's a possibility that the machine could be out of time & would need to be serviced by a sewing machine repair shop-as they have the tools for the job

Hi! Sounds like you're doing everything right to me, so let's see.

By not getting a straight stitch on the bottom, do you mean that the bobbin thread is loopy? If so, then most likely you have to reset the tension. Get a scrap of jeans material and practice on that....it would be great if you could use different color threads on top and in the bobbin, but that might not be practical if you don't have the jeans thread in different colors already.

You'll be adjusting the top tension, because even tho the top stitch looks perfect, it may not be tight enough to pull the bobbin thread up into the fabric where it belongs.

Sew a couple of inches on your scrap, then stop and check the bobbin thread. If it's loopy, you can also see the top thread on the underside. (Which is why using two colors is helpful.) With the pressure foot down, tightened the top tension just a bit. Sew a few more inches and check again. Keep on sewing, checking, and adjusting until you can't see any (or almost any) top threads on the bottom or bobbin threads on top.

Here are a couple of other ideas to check:

1. Make sure your bobbin is inserted correctly. If I happen to put one in backwards by mistake, the bobbin will make a lot of clanking noises.

2. Using your flywheel, lower the needle all the way through the stitch-making process to see if it's hitting anything along the way.

3. Oil your machine.

4. Make sure all the screws etc on your throat plate (also called needle plate) are tight. (I've had mine get loose and that will definitely throw a knock into the works!)

Check out these ideas and let me know if anything works, or if the problem is still there, ok?

Happy Sewing!

Robbie

hi there.
this is all i could find.go to this link and see if it helps you out.
Bobbin thread won come up with top thread Google Search

Y have broken the clip for the bobbin case you need to replace the bobbin case and oil up your machine properly.good luck.my email is nicodhem@yahoo.com to keep me posted.