Hello! Speaking of a 15 I could really use some help with one. I am new to the forum/only slightly less new to sewing. Def new to fixing vintage machines. Some background: got the machine from a friend who bought it overhauled from a guy who does that. I believe I have threaded both the upper and bobbin correctly, although that could be wrong. It is a treadle machine, serial number puts it at a 1936, not sure what the 15-xx number would be. After the first needle downstroke, as it attempts to cycle upward, it puts a lot of tension on the upper thread and breaks it when enough force is applied. I've done as much sherlocking as my newb sewing brain can muster and am lost for ideas about what's going on. I've played with the tension quite a bit, but again, nothing is necessarily being done correctly yet. Any ideas/advice/magic would be much appreciated.
Jake