GB/T 972-2008 English PDF (GBT972-2008)

This Standard stipulates the basic requirements for the type and size, profile size and deviation, technical requirements, marking and packaging of thread rolling flat dies for general purpose metric screw threads. This Standard applies to thread rolling flat dies for processing general purpose metric screw threads (GB/T 192~193, GB/T 196~197). Thread rolling flat dies are divided into three precision grades: grade 1, grade 2 and grade 3. Grade 1 applies to the processing of external threads with tolerance grades 4 and 5; grade 2 applies to the processing of external threads with tolerance grades 5 and 6; grade 3 applies to the processing of external threads with tolerance grades 6 and 7.