Dave, I've taken two of these apart and had a similar experience to you. Even used most of the same methods as you (i.e. drill and tap). Mine eventually came apart after a few months of occasionally applying PB blaster. After I got mine apart, they were not even in very good shape. Rust holes in the channels, splits at the ends. If I had it to do over again I would just put out the $350 and order a new frame. I've heard the aftermarket frames may not fit real well though.
