“ Men die because a part gives out. Machines wreck themselves because some parts are weaker than others. ”
 Henry Ford, My Life and Work (1922). copy citation

add

“In 1910 the French Department of Commerce and Industry took one of our steering spindle connecting rod yokes—selecting it as a vital unit—and tried it against a similar part from what they considered the best French car, and in every test our steel proved the stronger. The vanadium steel disposed of much of the weight. The other requisites of a universal car I had already worked out and many of them were in practice. The design had to balance. Men die because a part gives out. Machines wreck themselves because some parts are weaker than others. Therefore, a part of the problem in designing a universal car was to have as nearly as possible all parts of equal strength considering their purpose—to put a motor in a one-horse shay. Also it had to be fool proof.” source