“Clara,” he said calmly, “your drawing had no individual tolerance blocks. No surface finish notes. No ‘±’ anywhere. By international standard ISO 2768, part ‘m’ (medium) applies automatically for general dimensions. That means holes from 6 to 30 mm? ±0.2 mm. Angles above 120 mm? ±0.5°. Your 10 mm hole is allowed to be 10.2 mm max. Mine is 10.15—perfectly legal.”
“Herr Schmidt, I understand now. Keep the coarse edges at ISO 2768-m. But the sensor holes—make them tight.” tolleranze iso 2768
Clara stared. She had learned about ISO 2768 in university but dismissed it as “boring table stuff.” Now it had bitten her. “Clara,” he said calmly, “your drawing had no
Schmidt chuckled. “ Endlich (finally). Now you’re thinking like a pro.” By international standard ISO 2768, part ‘m’ (medium)
Moral of the story: Always specify when you need precision. Otherwise, the workshop will follow the silent song of ISO 2768—and you might not like the music.
That evening, Clara revised her drawing. For the sensor mounting holes, she added: . For the bracket’s outer edges, she left ISO 2768-m. The next morning, she called Schmidt.