Just to be clear, the wheel seemed to work fine, even before I discovered the anti-rotation washer was missing. Of course, I only rode the bike around the block a few times and up and down a bike path before I decided to start overhauling the rear hub and replacing all the bearings. I thought it might be a good idea to close up that gap just to hold everything a little bit more firmly. As it is now, the anti rotation washer sits in there at an angle, and I can imagine the edges might start digging in. I will try to tap the dropout back together a little bit; it is widened. But maybe I should leave well enough alone in this particular part of the bicycle. Is it well enough as long as the axle stays fixed?