The ISO designation system for toolholders for turning applicationsFor turning toolholders, as for indexable inserts, there is a similar ISO designation system.The system is designed so that each important feature and dimension of the toolholder is shown using a code system. This becomes the name of the toolholder.  This system has several advantages:Unique naming of a toolholder (supplier independent)All important features and dimensions are clearly stated in the nameSome code positions relate to the insert that can be used in the toolholder It's important to remember that the ISO designation system is not a system that standardizes the quality of the toolholders. Here is an example for external turning toolholders (metric) ISO standards Turning Here is an example for internal turning toolholders (metric) Do you want to know more?Contact Us Inline Content - SurveyCurrent code - 5fce8e61489f3034e74adc64

Image

Image

The inscribed circle (IC) is not something you can readily measure on a triangular insert. But the height (H) is easy to measure (a flat against one jaw of your caliper and a point against the other). The diameter of the inscribed circle is 2/3 of that measurement. So if you measure the height of an insert to be 0.374 (the radius on the point makes it a little less than the true height), the calculated inscribed circle is 0.249, or 1/4".

It's important to remember that the ISO designation system is not a system that standardizes the quality of the toolholders.

See also: Indexable inserts available at LittleMachineShop.com ANSI Turning Tool Designations ANSI Boring Bar Designations

These tables show the ANSI and ISO insert designations for indexable inserts for turning. A given insert can be specified in either ANSI (American) or ISO (metric) designations. Because many inserts are made in other countries, the ISO system is used frequently. Don't get hung up with spaces and hyphenation in insert designations. They are sometimes included for clarity, but there is little consistency among vendors.

Image

The first digit (fifth character) of the ANSI designation is the size, described by the inscribed circle. This illustration shows what that means.

The system is designed so that each important feature and dimension of the toolholder is shown using a code system. This becomes the name of the toolholder.