"The springs are the key to this item. The thread holders are relatively easy to find but I was convinced I could find some generic springs at my local big box home improvement store. In my case I really only needed the springs. Not the case. The generic spring assortment I bought contained springs which are either too short, too long, or not the correct weight. Shows Singer sourced it’s stuff carefully. Thank goodness for folks like you who support us weird vintage sewing machine rehab geeks. Frank J Taylor"
New Replacement Fold Down Spool Pins & Springs Fits Singer Model 500, 500A, 503, 503A