patricej

if your needle thread keeps breaking
-you may have a tension issue of some kind or
-your needle and thread may not work and play well together

singers are generally good machines but they can be a bit persnickity. consider starting from the bottom up.

take out the bobbin. in fact, take off the stitch plate and make sure the area under and around your bobbin case is clear of gunk, fluff, and other shmutz.

now, make sure you're using the right weight thread in your bobbin. a 50-wt or 60-wt thread is more likely to perform well in a singer than anything heavier.

moving up, check to make sure the entire top thread path is clean and clear of junk. there could be a snippet or two of old thread or bits of lint stuck in there somewhere.

the next thing is to ensure you are using a nice sharp needle. my singer throws a hissy fit if the needle is dull.

are you using a brand of needle your machine gets along with?

is the needle the right size for the thread you're using? try using the next larger size needle.

now that you're all cleaned and re-threaded, top and bottom, attach the foot you normally use for piecing. test everything with two layers of scrap fabric.

if all goes well, test again with two scrab fabs with a layer of batting in between (test sandwich).

now, put the walking foot back onto the machine, making sure the little arm thingie is resting on top of the needle screw. run your test sandwich back through a few times. fiddle with the foot pressure and top tension if you need to. it shouldn't require drastic adjustments to work.

if everything goes well until you attach the foot, and you're absolutely positive the foot is attached correctly, then you can be reasonably certain there's something wrong with the foot.