BT Tool Holders - BT30, BT40, BT50

There are two types of tools in CNC machinery: tool holders and cutting tools. There are other items related to tool holders, such as collets, set screws, wrenches, and other setup tools. Tools for CNC machinery are manufactured by a variety of brands and come in several ANSI standards. Similar to CAT tool holders, they have numerical designations that correspond to the size of the taper: BT30, BT35, BT40, BT45, BT50. The higher the number, the bigger the taper. BT tooling uses the same NMTB body taper as CAT40 and is symmetrical around the spindle axis – something CAT tooling is not. This gives BT tooling greater stability and balance at high speeds.

BT vs. CAT Tool Holders

BT tool holders accept both Imperial and Metric-sized tools; however, BT tools come in Metric sizes.  BT tooling looks similar to and can be easily confused with CAT tooling, but they are not interchangeable.

The difference between CAT and BT is the flange style, thickness, and size of the pull stud thread. BT tool holders use metric thread pull studs (retention knobs). Though both standards use the same NMTB body taper, BT tool holders are symmetrical around the main spinning axis while CAT tool holders are not. That makes BT tool holders better balanced and more stable at higher speeds.

Along with CAT and HSK standards, BT tool holders are among the most used in CNC machinery. They are durable and the best choice for high-speed machinery.

Overall Maintenance

BT tools use ATC (Automatic Tool Change) technology to maximize the speed and productivity in manufacturing. To ensure proper performance of your tool holders, the overall cleanliness of every tool holder, collet pocket, collet, and nut must be maintained. It’s important to remember that all of these components are manufactured to perform within tolerances of ten thousandths (.0001”) of an inch.

Any dirt, dust, oil, chips, or other contaminant left on the spindle, taper, flange, collet, collet pocket, or nut can cause poor T.I.R. (runout) which leads to the premature wear of the cutting tool, tool holder, and spindle mouth.

We highly recommend your shop implements a regular preventive maintenance program to protect your investment in cutting tools, tool holders, and collets, and reduce scrap. Damaged tools may cause some imbalance that can be critical at high speeds and precise CNC machinery.

Tapers & Sizes

BT tapers come in different sizes:

BT Tool Holders: Bottom Line

The wide array of BT holders available can make any job more efficient. Our team is here to help you select the most appropriate BT Holder for your machining tool needs. We sell an enormous selection of new and used holders by manufacturers and brands such as Command, Parlec, Kennametal, Lyndex, Sandvik, Techniks, Valenite, and more.

Shop Superior Machine & Tool’s selection of BT Tool Holders.