I have a 457 Singer sewing machine . It has a knob on the front base of the machine that has the letters d, r, f. This knob does something but I don't know what. Can anyone help me figure this out?

Check this page for some tips.

http://www.howtomendit.com/questions.php?id=92

Use search to find your model.


In the mean time here is a exploded diagram of your machine. I suggest you save it for future reference.


http://www.tandtrepair.com/Schematics/457.pdf

If you look lower on the initial page you will see where you can order the owners manual. It can be downloaded for a fee.