He downloaded it. Opened it. And there it was—the full, terrifying, beautiful logic of bolted joints. Formulas with Greek letters he’d only seen in nightmares. Tables for friction coefficients based on lubrication, material, and surface roughness. A flow chart that looked like the London Underground map.
The answer lies in a German guideline that has become a de facto international standard: . vdi 2230 part 1 pdf