wrench time
n.— «But the mechanics do not simply need better instruction, Mr. Joyce said. The typical mechanic, he estimates, puts in just four and a half hours of “wrench time” during an eight-hour shift. Much time is wasted traveling between subway stations.» —“$1 Billion Later, Subway Elevators Still Fail” by William Neuman New York Times May 19, 2008. (source: Double-Tongued Dictionary)