Please teach a method of counting work hours in a machine shop, where internal machining is divided into turning, milling, drilling, and planing, because the workpiece will use any of these four metho

Please teach a method of counting work hours in a machine shop, where internal machining is divided into turning, milling, drilling, and planing, because the workpiece will use any of these four methods Working hours are given empirically. The main thing is to look at the skill of the leader who gives the hours. For example, if you say, turning, milling, drilling, and planing all the hours of work time to add up, is the workpiece all the hours of work, plus preparation time. There's no way to calculate the wait time. Zero work hours are definitely higher because there is preparation time, and waiting time can never be counted as hours. After machining, you definitely have to wait until the drill press runs out.