A California dad became the envy of engineering buffs everywhere after constructing an over 100-year-old replica tank from scratch — a project that cost him a cool $50,000 and a year of his time.

The Mephisto tank first arose as a sort of evolution of armored cars that were already starting to find a role in combat, like the British Royal Naval Air Service's Rolls Royce Ghosts of 1914. Such ...