|When students have problems with their sewing machines that won't form stitches, almost always, the problem is that they have not inserted their bobbin correctly. It must unwind in only one direction and if you have it going the wrong way you are almost guaranteed problems sewing after a few stitches, so make sure you are inserting it correctly by referring to your sewing manual. Then use a sharpy marker and place an arrow for the correct direction somewhere on your machine or put a note on your machine
if you would rather not write on it. Even seasoned stitchers do this!
It doesn't seem to matter how many times I tell a student this. I think I will make a huge sign reminding them because I'm tired of repeating myself...