I just spent two weeks cleaning up a flamingo pink 1977 Schwinn Sierra which someone gave me. I am new to repairing bikes, and converting it to a single speed was something that I've been dying to learn how to do. (I did save all the parts, in case the purists freak out about the conversion). Today, I finished everything and was 5 minutes away from finally taking it out for a ride, when I realized that there is one major problem I never even thought to investigate: the diameter of the hole for the pedals on the crank arms is much smaller than that of the Speedplay Frog clipless pedals that I wanted to put on. And it's probably smaller than any pedals made since 1977.

Now I can't ride the bike!!!!!!!!!!!! I am on the verge of punching myself or crying, which ever comes first.

Is there any kind of adapter that I can find to attach to the crank arms so I can use my pedals with it? Unless I can find some, or unless it is possible to pay some metal shop to drill out the arms so they fit the size (which I don't think is possible), I cannot use the bike. I refuse to use platform pedals. The arms are not like modern arms that just have simple threading you can unscrew. They're housed in the bottom bracket.

Someone, please tell me that this problem is able to be solved!