CNC Shop - 21727 HSD ISO30 ER32 Tool Holder with CovernutThis is a balanced ISO 30 tool holder (cone) that is used for ISO 30 taper systems. All HSD ISO 30 ATC spindles use this cone. The HSD clamping system uses the pull stud at the end to pull the cone precisely into the spindles taper. Looking at ISO 30 as a replacement part? Tool holders are specifically balanced to work at high speeds. Although robust, damaged threads, worn pull studs or chipped surfaces on the tool holder, can severely impact your cut