STEEL ROOF WAS HARD TO COME BY, AT FIRST

Car enthusiasts waited more than two decades after the 1912 invention of the all-steel automotive body to get a steel roof over their heads.

It was worth the wait.

In 1935, General Motors made an industry splash by rolling out a sleek, all-steel turret top for all its car divisions.

The new roof quickly became the industry standard. It was one of those rare and timeless innovations that combines a cosmetic improvement with a number of functional ones, said Jesse Levine, vice president of the Ann Arbor, Mich., office of Seidman & Co., a New York investment bank that tracks automotive-supplier stocks.

Before GM adopted the all-steel turret top, car roofs had canvas in them and had to be resealed every winter.

The new roofs not only eliminated that inconvenience, but they also provided a more streamlined appearance that won consumer approval.

As cars were being built closer to the ground, people could see the roofs. They liked the sleek look of the turret tops.

Functionally, the all-steel turret top added tor-sional strength when attached to the car pillars, said Lev-ine.

While safety features weren't afforded the same gravity by consumers in 1935 as they are today, GM still used the additional structural integrity as a selling point.

Buick, for instance, in its 1936 marketing materials, promoted the 'luxurious turret top Body by Fisher as the safest, strongest body built.'

Even tooling was a plus, Levine said. Because the rest of the car body was steel, the carmakers had mastered the manufacturing process for steel, so adding a roof to the tooling mix was relatively easy, he said.

The turret top, with its functional and cosmetic enhancements, is the kind of innovation that today's designers are seeking, Levine said. In this age in which a premium is put on taking weight and cost out of cars, a component development 'has to do more than look pretty,' he said.

An all-steel car roof actually was invented 20 years before it began making its way onto production vehicles.

Industrialist Edward Budd, who built the first all-steel car body in 1912, championed a pillarless hardtop in 1915.

Advancements in steelmaking by 1935 made the all-steel roof an easier go. In 1932, for instance, Inland Steel in Chicago opened the first wide continuous sheet mill capable of making 76-inch hot-mill sheet desired by the auto industry.

Steel advancements combined with the reduced height of autos provided an impetus for the move to steel turrets.

As it turned out, the timing of the launch was good. Demand for new cars had built during the six dark years of the Great Depression.

In 1929, the year of the stock market crash, GM sold 1.44 million vehicles. By 1932, as the world economy collapsed, General Motors sold 522,062, or about a third of the total three years earlier.

When consumers finally had regained their appetite in 1935, GM sales totaled 1.23 million, then 1.7 million the following year on the strength of its new products, including the turret top.

Except for a recession-induced blip in 1938, GM would sell more than 1 million vehicles a year through 1941, when World War II caused American assembly plants to convert from commercial to wartime production. *

Dave Barkholz is a staff reporter at Crain's Detroit Business, a sister publication of Automotive News.