ISO 4014 specifies the characteristics of hexagon head bolts with threads from M1.6 up to and including M64, of product grade A for threads up to M24 and nominal lengths up to 100 mm, and product grade B for larger sizes.
This standard is the modern ISO equivalent to DIN 931. While very similar, there are minor differences in head dimensions (across flats) for M10, M12, M14, and M22 sizes.
Frequently Asked Questions
Can I substitute ISO 4014 for DIN 931?
In most structural applications, yes. However, due to the different wrench sizes on M10, M12, M14, and M22, you must ensure the appropriate tools are used during assembly.