Abstract: The bobbin case which is received by the looper has an upstanding generally cylindrical wall which surrounds the looper-thread bobbin. Forming part of the wall is a free-standing finger against which an end of a leaf spring rests. The looper thread, which has been withdrawn from the looper-thread bobbin and wrapped around the finger, is pulled through the constricted place between the leaf spring and the finger and then conducted through a threading slot provided by a radially-extending cam on the outer surface of the wall. The looper thread then comes against an inclined, downward-facing shoulder provided on the outside of the wall, slides down the shoulder, and passes finally into a long horizontal slot in the wall. The looper thread exits the bobbin case at an end point of the horizontal slot for being dependably caught by a thread catcher of a thread-cutting device.