I've used the riv-nuts style inserts from Fastenal, Harbor Freight and a few other places. They're very handy when working with plastic and sheet metal. Some of them at Harbor Freight are aluminum and pretty soft, I've stripped several of those. If they're available in brass, steel or stainless you shouldn't have a problem.
I've got things like this laying around because I usually over buy for a project, I figure I can find a use for the extras at some point.