When you go for the bobbin case be advised there is two kinds. One has a short slot and the other has a wide slot.
The short slot is usually found on end loading machines where the bobbin case moves left to right with the needle.
The long slot is usually found on front loading machines where the bobbin case is stationary and the needle alone moves.
Putting a short slot bobbin case in a front loader will be disastrous to the needle.
Sew-Classic has both types.
Joe