If you happen to be lucky enough to own an old  Singer Model 221 sewing machine, also known as a Featherweight, you might be interested in this...I fix Featherweights!  Cleaning, repairing, inspecting, adjusting and lubricating...I can keep your little beauty "singing."  This service is limited to the Greater Washington DC area.  Email me if you are interested...

Answer to Betty's Question regarding "Rat's nest at the bobbin"

The number one most likely cause is a position finger  that is not in the correct position.

The "Position Finger" is that piece of metal sitting at the twelve o'clock position on the bobbin face.  When the throat plate is removed to dust in this area, the finger is free to swivel, but when the throat plate is replaced, you have to be careful to adjust the position finger so that it is locked into the throat plate.

In other words...Does your machine look like this picture?  If not lift the throat plate to reposition the position finger.