Not all the towers along a transmission line are identical. Look closely at a tower where the line makes a sharp turn and you will likely find it is wider and beefier than other towers along the route. The added strength and weight are needed to resist the unbalanced pull of the conductors, which might overturn an ordinary tower. These special towers are called deviation or angle towers.
The transmission-line tower everybody knows is an Erector Set latticework of steel girders and diagonal braces. The techniques for designing and building these towers are the same ones used in constructing steel bridge trusses or crane booms. The individual pieces can be made cheaply from rolled steel and then bolted together on the site. This last point is more important than it might seem: transporting a fully assembled tower 100 feet tall is an awkward and expensive business.
The virtue of thin sheet metal in giving the greatest glitter for a grain of gold was exploited in the earliest days of metallurgy. However, before the days of rolled sheet and drawn wire, most metal objects were made by hammering and were basically three-dimensional in form.
[In contrast] look at the simple drop press — it’s unmodulated blow striking in a single direction symbolizes much of nineteenth-century mechanized production. To make multiple stampings, stacks of very thin metal sheets were superimposed under the hammer, and the final profile with moderately high relief was gradually achieved as finished sheets were removed from the bottom and new ones added at the top.
When the drop press was used to shape large areas of thin sheet metal, the aesthetic qualities of the surface became divorced from the underlying substance, and decoration became independent of the body needed to support it. In any object there is a natural relationship between the surface and the bulk, that is, between its one-, two-, and three-dimensional aspects. The fakery involved in applying gold or silver playing on a solid copper object is quite different from the deception of an ornately stamped piece of thin sheet brass. Compare a magnificent ormolu furniture fitting or even a gilded plaster picture frame with a cheap lamp base embossed in thin sheet brass. In the former, the surface is simply and honestly applied for its optical effect alone; in the latter the fakery is fundamental for it is dimensionally misleading.