I found a bolt just small enough to slide through the middle, but long enough to press with (pirated from the autozone valve compressor tool), then found a piece of pipe big enough for the insert to slide into, and another pipe sized a little smaller than the insert for pushing it out. Cut the pipes to a convenient length, then slide the bolt through the pipes and the insert, get some thick washers and a nut then start cranking. The screw head kept twisting off, but after re-welding it a few times it worked!
