Tool Holders 101: Cat, BT, HSK and More Info

Tool holders (toolholders) are the main facet that connects the machine tool to the tooling.. Their mounting styles are all different according to the interface. Their mounts can range from HSK tool holders, VDI mount, or the dated R8 styles.

All types of tool holders consist of 3 unique parts: the collet pocket, the flange, and the taper. There is static tooling which is not powered and there is live (driven) tooling which is not powered.

  • Taper: The taper part of a toolholder is cone-shaped. It is the part that is connected to the spindle when the tool is changed.
  • Flange: The flange is connected and attached to the automatic changer which moves the spindle and tool changer.
  • Collet Pocket: The collet pocket is fastened to the different collet nuts and is the region where the insert of the collet is secured.

A variety of tool holders surround the cutting tool (machine tool) so it remains intact in one position – while many other machining tools enable maximized clearance for small to large sizes.

Tool Holder Types

There are a wide variety of tool-holder types, they are indexed in the industrial machine tooling databases as such:

  • Machine arbors: These are driven by motors an are responsible for the turning mechanism of machinery tools.
  • Side cutter holders: These toolholder’s purpose is to hold the cutting tools in place.
  • Saw blade holders: These holders keep saw-blades in place.
  • Boring heads: They hold boring bars in places as well as other types of tool holders.
  • Tapping chucks: These keep operations in threading running smooth and also keep tapping tools in place.
  • Blank adapters: Depending on tasks in machining these are customizable for various applications.
  • End mill holders: Essentially for milling, these holders keep milling tools in place.
  • Outer diameter (OD) and inner diameter (ID): These are universal holders that are interchangeable with many types of tools for cutting.
  • Collet chucks: The variety of collet chucks work to hold different machinery tooling in place.
  • Milling or drilling chucks: Specifically designed to hold the placement for tools associated with drilling and million operations.

When you but tool holders, you should consider the exact mounting style that you need..

R8 is an old school mount developed by Bridgeport back in 1965. This part is obsolete and rarely used in modern machine tooling.

 The Morse taper (MT)  is manufactured in 4 different sizes. Every size differential contains a unique taper for ease of transitional changes in tool fittings and machinery tool use.

National Machine Tool Builders (NMTB) defined

The NMTB taper  type of toolholder was defined by (NMBT) National Machine Tool Builders. It is used in all types of milling CNC machinery and machines. The basic measurement requires a draw bar and stands at 3.5 inches per foot.

The CAT®  by Caterpillar®developed  customized mount style, is mainly referred to the  V-flange. It is the very basic tool for Cat CNC machines. All tool-holders built and manufactured by Cat consist of a numerical ID associated with taper size. (examples CAT-30, CAT-40, CAT-50 and CAT-60.)

Similar to the popular Cat tooling options is also BT tool holders. BT holders differ from cat because they are all symmetric and balanced within the rotational axis. BT toolholders contain the same standards of taper measures as the NMBT stud threads that use metrics to move.

Hollow shank tooling (HSK)  is a new innovation in tooling that is now used and implemented with various types of HSM machines. It is manufactured for quick changes in tooling and also comes in straight shank formats and dovetail formatting in machinery.


Tool Holders: Features and Applications

Tool holders features and application widely vary from those who have open coolant flow through the flange or are openly fed by components. Such models, brands, and makes (i.e.. Cat tool holders, BT tool holders, and HSK tool holders) are every bit (no pun intended) of the best examples for this instance. Every one varies in application and interchangeable abilities to adapt to size changes from small to large with the most gap of clearance possible. It is important to understand that every tool holder manufactured is tailored and customized for its specific purpose, task, and job. This makes a vast difference in operational and performance efficiency for use.