"Mechanical Fasteners; Technical Conditions of Delivery, Components with Electroplated Coatings" It provides specifications for the electroplated coatings
If you are designing a new product, do use DIN 267-9. Instead, refer to these modern equivalents:
It establishes that coatings must not cause thread dimensions to exceed the "zero line" (the basic profile) to ensure proper assembly. Bolt threads: Use tolerance positions g, f, and e prior to coating. Nut threads: Use tolerance positions Designation: