This is am old singer but the bobbins are not round...
they are about 1" long and skinny.
does this strike a "I know what it is"
with anyone ???

I have one also. They used to use them in treadle cabinets, but there are some like mine that has an electric motor. I would rather use it in a treadle cabinet as the motor turns it to fast and the shuttle can't keep up. The bobbin is a shuttle bobbin.

is it used for regular sewing ?

Yes it is, they do only straight stitch sewing. I had a Singer Treadle once that I sewed naugehyde purses on and it would go through 8 layers of material. Wish I still had it.

IT is called a shuttle bobbin or bullet bobbin case. They sew beautifully...
BTW, Keep the old bobbins for the machine, new bobbins to fit that bobbin case are just a hair off. You need to sand the tips a bit to make them fit.

I sewed my first quilt with a Singer treadle machine that had the shuttle bobbin My dad bet me I wouldn't finish it-- I did-- Bet was he had to by the backing Still got the quilt and the machine that was in "82 OHHH my said to much

My grandmother's Franklin has a bobbin like that.

piney