There can be so many reasons for the thread to break. I just got in from my shop - I had an old White ZZer machine I just got. I fooled and fooled with it. Gave up and worked on a Kingston made by Brother 15 clone. Thread kept breaking - two in a row???. Hint. They came at the same time... So since I was lazy and didn't do it, I changed out the needles. AHA. Maybe I wouldn't have had to rebuild the tensions and fool around with the bobbin tension and look for burrs all over the place after all. NAH - needed to do that anyway. Oh well, two very nice working machines. Then I got out an old Atlas - guess what - that one's needle was in backwards too. Go figure. These all must have come from the same place. At any rate all three work just fine now. The Atlas is sure ugly but a good working machine. I just looked - I had 10 calls today while I was trying to work. No wonder I was distracted. GGGGRRRRRRRRR. Next time the voice mail will get them.