Thread keeps breaking

SOURCE: CONSEW 206RB5 TOP THREAD NOT FORMING STITCHES AND BREAKING

you have your thread tension too tight that's why it is pulling the bottom stitch all the way through it looks good from the bottom but not good on top. Its pulled the stitch all the way through the material.
I had my own upholstery shop 18 yrs and tension gets you every time.Just loosen the top tension.

SOURCE: thread breaking on Simplicity Denim Star

Hi, when your thread breaks or frays right before in goes through the eye of the needle:

1. Change your needle - after awhile, the eye can wear down and cause your thread to break or fray, eventhough it looks like the thread isn't even going through the needle. When you change your needle, make sure to install a needle that is compatible with the thread you are using (see below).
   
2. If your thread still frays or breaks, make sure you've threaded your machine correctly. Most machines have a hook or bar right above the needle that your thread need to pass thru before you put the thread thru the eye of your needle. Sometimes that spot above the needle is really hard to get to, and sometimes the thread slips out. Always a good idea to double check. If you are still having problems, the needle you are using is probably the wrong size.
   

There are lots of needles on the market, and lots of threads. You need to make sure your needle is compatible with the thread you use for each project.

The most common needles are size 80 and 90 universal needles, which are fine for most sewing projects. But if you are using a specialty thread, you need to use a needle that is designed to work with that particular thread. For example, top stitching needles have a larger eye than a universal needle, because top stitching thread is thicker than sewing thread. The same is true for metallic thread - needles made for metallic thread an eye designed to allow the thread to pass thru without fraying. Further, if you using fine thread, you need a small needle.

FYI - unfortunately, thread sizes do not correspond directly with needle sizes. Small needle numbers indicate a needle with a small eye. But the smaller the thread size, the larger the thread. For example, size 50 thread is very fine and would usually be used with a size 70 needle. Size 30 thread is fairly thick and would probably be used with a size 90 top stitch needle.

Hope this helps, and remember, you should always change your needle after about 10 hours of sewing, no matter what size needle you are using. If you have more questions, please post again. Thanks, Ginny

SOURCE: My lowerlooper thread keeps breaking. I can only

The lowerloop thread kept getting cut by the upperlooper.....I rethreaded the machine in order and then made sure that the lowerlooper thread was UNDER the part of the machine that makes the looks the loopings (silver part that comes to a point on the right side of the needles...sorry I don't know what to call it) and the upperloop was ON TOP of the same part.....it started working great. I actually have very nice tight stitches now.

SOURCE: top thread keeps breaking

This sounds like a backwards needle. Take out the needle and when you re-insert it back in, make sure that put the flat side to the back.

SOURCE: thread keeps breaking

check to see if there are any burrs in that area