On two occasions, TSA employees at the airport security screening area have taken my nail clippers away. They were ordinary nail clippers, no knives or scissors attached.
So I was surprised to see that nail clippers and nail files are not forbidden items, according to the TSA's own published list. You can also bring metal butter knives, knitting needles, blunt-tipped scissors, and toy weapons ("if not realistic replicas") in your unchecked baggage.
Maybe I'l bring a copy of this list with me the next time I travel. It might come in handy. Link