Doug,
That is called a "Rivnut".
rivnuts - Google Search
You will have to find out who locally sells them. They have them at Harbor Freight
Harbor Freight Tools ,but who knows what the quality is.
You want the ones with the ribbs on the sides. That keeps them from turning. You still only have to drill a round hole, tap them in with a hammer/mallet and then collapse them. You can probably get away with an allen bolt and a thick washer to install them. Make sure that you get the steel ones. The aluminum ones are too week and the stainless ones are harder to install.