Name for a tool interface with hollow shank taper, which is standardised in accordance with DIN 69893.
Hollow shank tapers are about 30% smaller and about 50% lighter than steep-angle tapers. They however are design related more rigid and due to the optimal supporting surfaces have a higher positioning accuracy in the machine holder. Hollow shank tapers are suitable for higher rotation speeds because of the increasing clamping force at a higher centrifugal force. The clamping bolt is unnecessary.
The hollow shank taper HSK-F63 was established in woodworking during the 1990s. Because of his more favourable clamping force at an only slightly higher weight he was able to replace the HSK-F50 at an increasing rate. Today most of the CNC-machining centres are built equipped with the tool interface HSK-F63. (see also HSK-E63 bzw. HSK85)