How A Car Body Innovation Revolutionised the Way We Build Skyscrapers

By Rachel Swaby on at

Certainly you've assembled a piece of Ikea furniture and experienced that special kind of frustration that comes with realising the screw holes don't line up and you have to take everything apart and put it together it again. Now imagine this problem at 750 feet in the air with massive steel girders instead of particle board. When those holes don't line up, it's a whole different kind of frustration.

And it's incredibly dangerous. Until a few decades ago, these holes for steel girders were mostly bored on the ground before the parts were hoisted up. It was a cheaper and safer place to operate because the machinery for making holes in hefty steal is freaking heavy. Workers measured carefully while on the ground to avoid acrobatics up high.

But sometimes alignment problems happened, and workers had to ascend the structure lugging a 100-pound drill. Once they had the tool up there, breaking through thick steel is no easy task. It requires a lot of torque, which is never fun at precarious heights. To stabilise the the equipment, the machine was magnetised so it would stick to the beam. That helped! But it was far from ideal. It could still fly loose if the drill got stuck, possibly launching a worker or two with it.

An innovation in car body repair made the task both safer and easier. In the 50's, Douglas Hougen puzzled over a way to unfasten spots welded together (spot welds) between car panels without damaging them like the state-of-the-art tool at the time, the impact air chisel, tended to do.

Hougen's tool was essentially a hole saw—a hollow tube with sharp edges that carved out a cylinder of metal rather than pushing it through like a regular drill. But Hougen improved the blade by tweaking its geometry. The auto body industry adopted the device quickly, but Hougen had hopes for also taking on manufacturing with a heavier-duty hole cutter he called the Rotabroach. But the auto-manufacturing industry was a behemoth and was not quick to change its ways. Technicians already used a twist drill, and they weren't interested in completely overhauling the tools of their trade.

"These companies had thousands of people on their payrolls and engineers coming out of their ears, all devoted to designing better twist drills," Hougen writes in his memoir, Inventing as a Way of Life. "Here I was, only a body repairman, and I was entering their field with a drilling tool technology they hadn't dreamed possible."

So in 1974 Hougen decided to take it to an entirely different industry. The Rotabroach Annular Cutter, Hougan figured, could make a better magnetic drill for skyscraper builders: one safer, lighter, and cheaper than what was currently available.

The Rotabroach required less torque than the solid twist drills available, so it could be less hefty—just 13 kg compared to the existing 45 kg models.

Initially Hougen's tool caught on for cutting smaller holes: thirteen-sixteenths of an inch, seven eights of an inch and then the three quarters of an inch markets. Construction companies liked the product, but he was hungry to take on more of the hole-cutting industry.

He set his sights on the two-incher. No one had ever used a magnetic drill to cut a hole that large because it requires a machine with a crapload of torque. Hougen had his eyes on a motor promising 150 foot-pounds. The problem with that much power is that if the drill seizes, even the Hulkiest operator wouldn't be able take control if the tool started spinning. It was a dangerous scenario for a worker in an already precarious location.

Hougen decided to anchor the tool by boring it directly into the I-beam. This inserted point provided a foothold without damaging the metal structure. Should the drill get stuck, the grip would have to be dragged through a steel surface before the tool started spinning.

The anchor worked well, but what if the insertion didn't sink in properly? A mistake could still send someone flying. The tool needed an emergency out—something to stop it if other systems failed. So in the middle of the magnetic plate, where the tool was attracted to the steel, Hougen added a toggle switch that would kill the whole operation should there be any unexpected shift between the tool and the beam it was secured to.

The safety measures, lightness, and ease of use catapulted Hougen's company to the front of the magnetic drill market. Hougen sold more magnetic drills than all other companies combined, and he's gone on to supply nuclear subs, space shuttles, and yes, finally, the automotive industry with his innovative hole-punchers.