ISO 5609-1:2012 specifies the code for the designation, styles, general dimensions and calculation for corrections for tool holders for internal turning with cylindrical shank. It is intended to be used in conjunction with, and is completed by, ISO 5609-2, ISO 5609 3, ISO 5609 4, ISO 5609 5 and ISO 5609-6.

These tool holders are primarily intended for indexable inserts made of hardmetal, ceramic or other cutting materials to be mounted by clamping and to be used for internal turning operations.