Hello! First post, sewing newb here. If this post is more appropriate elsewhere, my apologies in advance, and some direction would be appreciated. I just procured a recently overhauled 1936 singer model 15. It seems to cycle beautifully, although won't stitch more than once without breaking the upper thread. From all I can gather it seems to be a tension issue, for which my ignorance can not figure out a fix. Being a bicycle mechanic and used to problems being rather big and easy to spot, this tiny, perfectly orchestrated, although fairly simple machine is blowing my mind. Any advice on how to troubleshoot this would be so appreciated. I look forward to learning from you all!
jake