After cutting the old bolt off it sounds like getting a new blind nut will be near impossible without surgery, so a couple options I can thing of,
1- Epoxy in a 4-40 threaded insert, they make a few different styles,
2- Cut out a small area epoxy in a ply or hardwood block, drill and tap for the new bolt
inserts
http://www3.towerhobbies.com/cgi-bin...DxcaArCn8P8HAQ
https://www.google.com/webhp?sourcei...eaded%20insert
good luck