It's getting to be a broken record. February was another up month for U.S. manufacturing as output increased 0.4 percent. Output rose 0.7 percent in January after jumping 1.5 percent in December—the biggest gain in 5 years. Also, U.S. manufacturers added 31,000 jobs in February, on top of adding 227,000 jobs in 2011. Of course, the big question is how long can this last?