That piece is called the bobbin case control lever, and it opens and closes as the hook turns. Turn the hand wheel until it opens, and feed the thread through. Then let the machine pick up the bobbin thread. If it doesn't open, it may need to be adjusted slightly.
No one lives forever, the trick is creating something that will.
Last edited by DanTwoLakes; 11-22-2014 at 12:19 PM.