MCLEAN, VA—U.S. machine tool sales totaled $506.89 million in December, according to AMT—The Association For Manufacturing Technology. That’s an increase of 32.7 percent from November and 4.7 percent from December 2013. All totaled, U.S. machine tool sales exceeded $5 billion in 2014, an increase of 3.1 percent compared with 2013. MORE