Sometimes you find yourself taking the bobbin case of a Slant-o-Matic out, maybe to remove an errant thread, clean the lint out or whatever.  Strangely, putting it back in isn’t as easy as taking it out.   Or maybe you thought it was good, but the machine’s locked up, or it just doesn’t look / feel right.

There’s “groove” on the bobbin case, it needs to straddle the ledge on the inside of the hook. It’s really easy to seat the bobbin case under the ledge but this isn’t correct. When the bobbin case is correctly positioned, it will almost “disappear”. The bobbin case will be flush with the top of the hook, all you’ll see is a seam between the two. Once it’s in place, and you put the “positioning arm” back into place, it will hold everything tight.

Here’s a photo for you of a properly seated bobbin case:

Notice how it sits flush, and there’s only a thin seam to show there are two pieces? That’s correct. Now slide the black retaining lever (positioning arm – in place in this photo) into place and you’re ready to sew.