BT (MAS 403) DIN ISO 7388-2 Technical Information
BT tool holders are widely used in CNC machining for reliable taper performance, good balance, and compatibility with automatic tool changers in high-productivity environments.
Stable, Balanced, and Production Ready
BT holders are designed for dependable spindle interface performance in machining centers. Their symmetrical design supports better balance at higher speeds and makes them a strong choice for precision CNC applications.
BT vs CAT Tool Holders
BT Tool Holders
- Symmetrical around the spindle axis for improved balance.
- Well suited for higher-speed machining applications.
- Use metric-thread pull studs or retention knobs.
- Commonly used with CNC machining centers and automatic tool changers.
CAT Tool Holders
- Different flange design and flange depth compared to BT holders.
- Use a different pull stud standard.
- Appear similar to BT holders, but are not interchangeable.
- Share the same basic NMTB taper concept, but differ in interface details.
Key Differences
- BT holders are symmetrical, while CAT holders are not, which gives BT holders an advantage in balance at higher speeds.
- The flange design, flange depth, and pull stud thread specification are different between BT and CAT systems.
- BT holders use metric-thread retention knobs, whereas CAT holders use a different standard.
- BT and CAT holders are not interchangeable, even though they appear similar.
Application Advantage
BT holders are among the most widely used tooling systems in CNC machining, along with HSK and CAT standards. They are especially suitable for high-speed machining centers and are commonly used where automatic tool changing is required for higher productivity.
Note: Always match the holder standard, pull stud type, and spindle specification correctly to ensure safe and accurate machine operation.
