Thanks again for the ideas. I have a newer machine and don't want to take chances with the magnetic thing, but it sounds like a good idea for some machines.
I have a Pfaff expression 2 and I am sure there ought to be a mark on here at the 1/4 somewhere, but when I measure all of the marks, none is 1/4 inch. Not to worry, I will buy a new foot today, plus my husband fixed mine and my sister lent me one. I am back in business, for sure!