General Administration of Quality Supervision, Inspection and Quarantine of the People‘s Republic of China
Latest
GB/T 39542.3-2020
Scope
This part of GB/T 39542 specifies the bending strength and test methods of black lead cores with a hardness grade of HB for technical drawing mechanical pencils.
GB/T 39542.3-2020 Referenced Document
GB/T 39542.2-2020 Mechanical pencils for technical drawings—Part 2:Black leads—Classification and dimensions
GB/T 39542.3-2020 history
2020GB/T 39542.3-2020 Mechanical pencils for technical drawings—Part 3:Black leads—Bending strengths of HB leads