There’s a sheet of paper within reach of you right now. Unless you’re in North America, it measures 210 by 297 mm (8.3 by 11.7 in).
Nobody picked those numbers. They fell out of a requirement.
In 1786 Georg Christoph Lichtenberg wrote to a friend about a sheet that would keep its proportions when you cut it in half. That’s the entire specification. One condition, written down before anything was drawn. Work the math and exactly one ratio satisfies it, the square root of two, and every dimension follows from there.
Walter Porstmann turned it into a published standard in 1922. By 1975 it had become ISO 216. Today nearly every country on earth uses it, the United States and Canada excepted.
Requirement first. Shape afterward.
That order is most of what people mean when they say German engineering, and here it has a name.
Function First, Shape Afterward
The verb is konstruieren. English renders it as to design, which isn’t wrong and isn’t quite right either. Design in English leans toward how a thing looks. Konstruieren means working out by calculation what shape a thing has to take in order to do its job.
There’s a job title to match it. A Konstrukteur is the person who does that work. It isn’t the same as an engineer in general, and it certainly isn’t a designer in the styling sense. English needs half a sentence where we get by with one word.
What this country did with it was make the thing teachable. The procedure runs roughly like this:
- Write down what the thing must do, in terms of function, without naming a single part.
- Break that down into sub-functions.
- Find a working principle for each one, and here you’re allowed to be inventive.
- Combine the principles into a concept, then give the concept a physical form.
- Draw the details last.
The Association of German Engineers published that as guideline VDI 2221 in 1973. Gerhard Pahl and Wolfgang Beitz wrote the textbook, Konstruktionslehre. It went into five languages, and in English, as Engineering Design: A Systematic Approach, it became the standard international reference on the subject.
That’s the part that usually gets missed. Plenty of countries produce brilliant engineers. We wrote down how to be one, gave the procedure a guideline number, and then examined people on it.
What It Leaves on the Finished Thing
You can read the method off the object once you know what to look for.
Margin comes first. A component rated for a given load is built to take considerably more, because the calculation carries a safety factor. That factor isn’t a matter of taste. It’s written into the standard for that class of part.
Then serviceability. Wear parts sit where a hand can reach them, and whatever fails first is whatever comes out first. That ordering gets decided at the drawing stage, years before anyone picks up a wrench.
Then spare parts. Ordering a seal for a twenty-year-old machine and actually receiving one is ordinary here. It’s ordinary because the seal was a standard part to begin with. Normteile, the catalog components, do half the Konstrukteur‘s work for him. The screw, the bearing, and the seal are all specified somewhere else already, so the design can spend its effort on whatever is actually new.
Then modularity. One frame, one drive, one control cabinet, and the variants come from swapping modules instead of redrawing the machine. It’s how a small manufacturer offers a product line with dozens of configurations in it.
And the documentation is part of the delivery rather than an afterthought. The machine turns up with drawings that match the machine.
The Framework Around It
None of this runs on individual virtue. There’s a scaffolding underneath, and it’s where this tradition parts company with most others.
Normung, or standardization, is the first leg. DIN, the German standards institute, was set up in 1917, and there are now over 30,000 standards. That’s the catalog the Normteile come from. A part made in one town fits a machine built in another. Somebody sat down first and agreed on the thread, the tolerance, and the test.
Independent inspection is the second. The TÜV, the technical inspection association, checks other people’s work for a living, from elevators and pressure vessels to every car on the road here. The principle is what counts: a standard on paper does nothing until somebody outside the company verifies that it was met. That verification is what holds the level up, rather than the assurance that it’s up.
Training is the third, and plenty of the engineers here never saw a university. They came through the dual system instead. That’s three years split between a company and a vocational school, with the final exam set by the trade rather than the school. Above it sits the Meisterbrief, the master certificate, which a range of trades require before you may run your own shop and take on apprentices.
Then there’s the piece visitors most often miss. To hold a professorship at a Fachhochschule, a university of applied sciences, you generally need five years of professional practice after your degree. At least three of those years have to be outside any university.
The person teaching you to design a gearbox had to design gearboxes for a living first.
Where All of It Turns Up
Ask what German engineering builds and most people say cars. The largest field is mechanical engineering, and it employs more people here than carmaking does.
Under that one heading sits a startling range. Machine tools and printing presses, packaging lines and agricultural machinery, pumps and drives, and the robots that assemble things inside other countries’ factories.
Then there’s plant engineering, which deserves to be better known than it is. German firms don’t only sell machines. They build entire production facilities abroad and hand over the keys: chemical works, steel mills, cement plants, and the power stations to run them. Roughly four fifths of that work goes to customers outside the country, which makes it the German economy in miniature. The largest single market for it is the United States.
Electrical engineering and process engineering are separate disciplines with their own degrees, and so are civil and precision engineering. Medical technology is a world of its own again. Tuttlingen, a town of 35,000 on the upper Danube, holds around 400 medical technology firms by itself.
The method doesn’t change between any of them. Function, then principle, then form, then the drawing.
Which brings us back to the sheet of paper. Pick it up and fold it in half. The halves are the same shape as the whole, precisely, with nothing trimmed off and nothing left over.
A man wrote down one condition in 1786, and everything after that was arithmetic. That’s the entire trick, and it has been sitting in your printer tray the whole time. :-)
For who does this work and who they do it for, start with German business. The firms the tradition produced sit on German companies.