Did you check the bobbin case for threads? And have you oiled and greased it? I just finished cleaning up a featherweight that hadn't been used for years and found that it was so dry that the disks underneath the bobbin race(?) needed to be taken out and cleaned thoroughly; the little grooves in it were packed with gunk and caused the thread to jam. Even a small piece of thread lodged behind it will stop the needle from moving up or down and the hand wheel won't budge either. I put a dap of Tri Flow between the disks before putting it back together and problem was solved. It runs great now. Just my two cents.