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Differences between DIN and ANSI Specifications for Impact Sockets

  • 2016-08-01

Most impact sockets are manufactured to suit ANSI or ASTM specifications as set out by the American National Standards Institute, or to meet DIN specifications as set out by the Deutsches Institut für Normung (German Institute for Standardization). The three main differences between these two industry standards are listed below.

1)  ANSI/ASTM specifies socket sizing in millimeters as well as fractions of inches, while DIN uses only millimeters.

2) ANSI/ASTM and DIN Socket standard show different diameter sizes for an impact socket of a given hex size.

3) They each specify different tolerance requirements for an impact socket of a given hex size.

These three points have a significant influence upon material weight, inventory, production and processing equipment requirements.

For example, for impact sockets with these respective square drive hole measurements, the specifications according to the German standard DIN 3121 (ISO 1174-2) and the US standard ASME B1107.4M-2012 are shown in the table below.


The table demonstrates that DIN requires stricter tolerance than ASME. For the ½-inch drive, DIN allows 0.11 tolerance while ASTM allows 0.218, resulting in a discrepancy of 0.108mm. In other words, DIN and ANSI impact sockets are not the same and their differences should be carefully noted.

As a leading Taiwanese manufacturer of impact sockets, Tien-I designs and produces standard and OEM impact sockets to satisfy the specific requirements of our customers in different countries. If you have any questions or special requests, please feel free to contact us.