I am not recommending this, and over time will see how it pans out. I found that an unused 1/8" dia. aluminum pop rivet with shank removed fits perfectly with flared side filed a little and polished. Some have told me that the aluminum in the pop rivet is harder than the case back, which might provide problems. I dunno, it has no pressure against it when running due to the pull of the prop which keeps it from being pressed against the back.
TIme will tell.