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Common Taper Designations Explained

Posted by Travers Team on Dec 13, 2023 7:38:33 AM
Travers Team

Welcome to the innovative world of spindle tapers, a cornerstone in CNC machining that has dramatically transformed manufacturing efficiency and precision. In today's fast-paced manufacturing landscape, spindle tapers stand out for their superior design and functionality compared to conventional tapers used in many current machining setups.


Collet chucks, arbors, and holders equipped with spindle tapers offer a multitude of benefits over regular tapers. Their precision-engineered design ensures a more secure, accurate connection between the spindle and the cutting tool, a vital factor in achieving high-quality machining results. This tight coupling leads to significantly reduced tool chatter, enhanced cutting precision, and extended tool life, making spindle tapers a preferred choice for modern CNC operations.
Additionally, spindle tapers provide greater stability and balance during machining. This stability is crucial when working with high-speed operations or complex materials, as it minimizes errors and maintains consistent quality. The variety of spindle taper types, each tailored for specific applications, allows for unparalleled flexibility and adaptability in diverse machining environments.


Taper Designations

MT (Morse Taper):

morse taper

While primarily used in manual machining applications, MT tapers are also found in some CNC machines, especially in smaller, more cost-effective setups. See our corresponding article on how to identify and determine the size of your morse taper for additional assistance.


CAT40:cat 40 taper

CAT40: Balancing Versatility and Strength
CAT40 refers to a type of spindle taper widely used in CNC machining centers. The term "CAT" stands for "Centered on the Taper," and the number "40" represents the nominal diameter of the taper in millimeters at a specific point (measured approximately 1.7 inches or 43 mm from the small end of the taper).


Key Characteristics of CAT40:

Taper Angle: CAT40 tapers have a taper angle of 7/24, meaning the angle between the taper and the centerline of the spindle is 7 degrees.

Applications: CAT40 tapers are commonly used in a wide range of machining applications, offering a balance between rigidity and versatility. They are suitable for machining operations on various materials, including metals and plastics.


CAT50:cat 50 taper

CAT50: CAT50 is another type of spindle taper used in CNC machining centers.


Key Characteristics of CAT50:

Taper Angle: CAT50 tapers also have a taper angle of 7/24, similar to CAT40 tapers.
Applications: CAT50 tapers are larger and more robust than CAT40 tapers, offering increased rigidity and stability. They are often used in heavy-duty machining applications, especially when dealing with large workpieces or materials that require higher cutting forces.

In summary, both CAT40 and CAT50 are standardized spindle tapers widely utilized in CNC machining centers. CAT40 is suitable for a broad range of applications, while CAT50 is preferred for heavy-duty machining tasks that require additional strength and stability. The choice between CAT40 and CAT50 depends on the specific machining requirements, such as the size and material of the workpiece and the cutting forces involved in the operation. 


BT30: The Precision Experts

BT30 taper

BT30: refers to a specific type of spindle taper


Key Characteristics of BT30:

Taper Angle: BT30 tapers have a taper angle of 7/24, meaning the angle between the taper and the centerline of the spindle is 7 degrees.
Applications: BT30 tapers are used in precision machining applications, especially in industries where high-speed and high-precision cutting is essential. They are commonly found in smaller machining centers and are ideal for tasks requiring intricate detailing and accuracy.

Note: ISO30, INT30 and BT30 all have the same dimensions, but differ at the small taper end – some will have facility for a draw in bolt and some will be equipped with a draw stud for quick-changing, and those with draw stud have no parallel portion after the taper as with draw stud types.


HSK: High Performance CNC Machining

HSK taper

HSK (Hohl-Schaft-Konus): a standardized system for tool holding widely used in high-performance CNC machining applications. The HSK system offers excellent accuracy, rigidity, and repeatability, making it suitable for high-speed machining and heavy cutting operations. Within the HSK system, different styles or configurations exist, denoted by letters such as A, B, C, and D. Each style is designed for specific applications and requirements. Here's what the most popular styles represent:

HSK-A and HSK-C: serve applications requiring moderate torque and moderate-to-high spindle speeds. (Type A is for automatic tool changing, and Type C is for manual changing.) HSK-A is characterized by a short and compact design. It is suitable for applications where space is limited, such as in milling and drilling operations. HSK-A tapers are used for light to medium cutting tasks.


HSK-B and HSK-D: are designed for high torque applications with moderate-to-high spindle speeds.


Download & print your free taper dimension chartTaper Dimension Guide

Download and print our taper dimension pdf for a quick reference table that will help you determine your machine's taper correctly, every time! Our comprehensive chart includes 'at a glance' listing of the most popular taper styles including BT Shank, CAT Shank, Jacobs Taper, Morse Taper, NMTB Shank and R8 Shank.

Download Taper Chart


Topics: Accutek, Machine Tool Accessories, Shark Tools, Holders



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