Your model 221 is called a Singer Featherweight. It recently underwent a large surge of demand for quilters - who only need the straight stitch for a standard quilt.

The machine is small enough and light enough that it can be carried to quilting club meetings and sewing events. For a while, it commanded pretty high prices.

It is also famous for the quality of the stitch that it makes. I think you are seeing that. Looks like professionally sewn clothing.

Part of that quality comes from being designed for only straight stitches. The needle just ploughs along straight ahead. The zigzag and other modern machines are designed to allow the needle to be moved from side to side, and as a result there is often some extra mechanical play that shows up as a poorer quality stitch.

With good care and frequent oiling and lubrication, you machine could last another 50 or 100 years still cranking out great stitches.

Enjoy.

I passed up the chance to buy one for about $15 four years ago. I didn't know what it was back then, and because of that was afraid to buy it. Fixed up, those things could go for over $200 at one time.

Enjoy.