How a Tower Crane is Assembled 🏗 To rise to its maximum height, the crane grows itself one mast section at a time! The crew uses a top climber or climbing frame that fits between the slewing unit and the top of the mast. Here's the process: 🏗 The crew hangs a weight on the jib to balance the counterweight. 🏗The crew detaches the slewing unit from the top of the mast. Then, large hydraulic rams in the top climber push the slewing unit up 20 feet (6 m). 🏗The crane operator uses the crane to li