Pneumatic nailers have become so commonplace with both framing and finish crews that one builder I know calls the standard hammer "one of those things you hit things with." Even the the little bit of usefulness the hammer retains— for "making adjustments" and getting into tight spots—is now being challenged by technology in the form of the Danair air hammer. And it may not be long before other common tools, such as the caulk gun, fall by the wayside as well. Close Quarters Nailgun At first glance, the Danair RN 16-20 (Danair Inc., P.O. Box 3898, Visalia, CA 93278; 209/734-1961) looks like a palm sander, except in place of a pad it has a snout that bangs nails. It's easily