The Difference between BT and HSK Tool Holders

In general, BT Tool Holder is the most commonly used TOOL HOLDER in cutting, while Hsk Tool Holder is the most widely used Tool Holder in high-speed cutting.When the taper of Bt Tool Holder is 7:24 And the rotational speed is about 10,000 r/min, the tool holder-spindle system does not appear obvious deformation. However, when the spindle rises from 10,000 r/min to 40,000 r/min, due to centrifugal force, the end of the spindle system will appear large deformation, and its diameter jump will increase from 0.2 m to 2.8 M. Clearance between tool holder and taper hole of spindle will appear obviously, which seriously affects cutting characteristics of tool, so BT tool holder can not be used in high-speed cutting generally.

The centrifugal force at high speed causes the deformation of BT tool shank-spindle system. The structure of HSK tool shank taper is different from that of BT tool shank. It is a new type of high-speed taper tool shank. It uses the double positioning method of taper and end face. Under the action of enough tension force, HSK 1:10 hollow tool taper shank and spindle 1:10 taper hole are between the whole tool shank and spindle. Friction occurs on the cone and support planes to provide radial positioning of the enclosed structure. The German standard of 1:10 HSK vacuum tool holder is DIN69873. There are six kinds of standards and specifications, namely HSK-A, HSK-B, HSK-C, HSK-D, HSK-E and HSK-F. There are three kinds commonly used: HSK-A (automatic tool change with internal cooling), HSK-C (manual tool change with internal cooling) and HSK-E (automatic tool change with internal cooling, high speed).
BT TOOL HOLDER

BT and HSK are used to transfer torque through keys, and some tool shanks are used to transfer torque through their own shapes (such as Capto interface). Generally, the tool shanks that transmit torque through their own shapes are said to be larger and more stable, especially at high speed. The spindle taper holes in machining centers are usually divided into two categories, i.e. taper 7:24. General purpose system and 1:10 HSK vacuum system. The universal tool holder with taper of 7:24 usually has five standards and specifications, namely NT (traditional type), DIN 69871 (German standard), IS0 7388/1 (international standard), MAS BT (Japanese standard) and ANSI/ASME (American standard). The German standard of NT type tool holder is DIN 2080, which is to tighten the tool holder by pulling rod on traditional machine tools, also known as ST in China; the other four kinds of tool holders are tightened by pulling nails at the end of the tool holder on the processing center. At present, DIN 69871 (JT) and MASBT are the two most widely used tool holders in China. The tool holder of DIN 69871 can be installed on the machine tools of DIN 69871 and ANSI/ASME spindle taper holes. The tool holder of IS0 7388/1 can be installed on the machine tools of DIN 69871, IS0 7388/1 and ANSI/ASME spindle taper holes.

HSK TOOL HOLDER