Never seen that before, but yes, it's fixable. Take a wire brush to both sides, so that you can get good electrical
contact, drill through the top side and into the bottom with an appropriate tap size drill bit, tap the bottom part and re-drill the top part to the body size. Bolt the two together. Drilling lead is a little odd - it gums up drill bits, so it's in and out repeatedly as the bit progresses.
10-24 would be about right. Here's the tap drill and tap if you don't have them, and use the next size up in your drill bit set for the body hole in the top part.
Good luck with it.
I'm going to move your thread to "Construction, etc." for other opinions.