Choosing the Correct Insert for Your Boring Bar

by Bernard Martin

Choosing the right insert for boring applications is critical for optimizing performance, achieving desired surface finishes, and extending tool life. The insert's geometry, material composition, and coating determine its cutting behavior, wear resistance, and suitability for specific materials and machining operations.

Understanding the characteristics and applications of insert types allows you to make informed decisions that improve efficiency, productivity, and overall outcomes in your machining processes. This short guide aims to provide a comprehensive overview of insert types compatible with Everede boring bars and how their distinctive features contribute to profitable  machining.

Everede boring bars accept a selection of standard carbide inserts.  Understanding how and why certain style so inserts are sued for the different types of bars will help you improve tool life and finish.  Everede offers inserts in the following geometry:  CDCD, TDGB-3, TDGH-3, & TDGC, TPGB-3, TPGH-3, & TPGC-3 and WCGT (Trigon) Inserts.

As you already know, the ANSI and ISO insert designation systems provide a standardized way to describe the shape, angle, and other attributes of cutting inserts used in machining operations. The first letter of the insert code indicates the shape of the insert, while the second letter refers to the clearance angle.

Here's how CD, TD, TP, and WC (Trigon) style inserts compare based on these designations:​

CD Style Inserts

• Shape: "C" refers to an 80-degree diamond with 4 cutting edges, offering a balance between cutting efficiency and edge strength for a variety of turning and boring operations.
• Clearance Angle: "D" represents a 15-degree clearance angle, ideal for preventing insert drag on the workpiece in smaller diameter bores but may lead to reduced cutting edge strength in larger diameters.

---

DC Style Inserts

• Shape: "D" stands for a 55-degree diamond, which provides a sharper point than the 80-degree diamond, potentially offering better cutting precision and reduced cutting forces, suitable for detailed work.
• Clearance Angle: "C" with a 7-degree clearance angle offers minimal clearance, similar to WC inserts, making DC inserts well-suited for applications that benefit from a stronger cutting edge in larger diameter bores or where precision is key.

---

TD Style Inserts

• Shape: "T" denotes a triangle shape with 3 cutting edges, known for efficient cutting action though it might provide less edge strength than some diamond shapes.
• Clearance Angle: "D" with a 15-degree clearance angle, suitable for applications requiring substantial clearance to avoid workpiece contact, especially in confined spaces.
  

---

TP Style Inserts

• Shape: Still indicating a triangle shape, this design utilizes three cutting edges for effective material removal.
• Clearance Angle: "P" indicates an 11-degree clearance angle, offering a compromise between edge strength and sufficient clearance to prevent dragging, suitable for a wide range of applications.

---

WC (Trigon) Style Inserts

• Shape: "W" signifies an 80-degree trigon, a modified diamond with 6 cutting edges, combining cutting edge strength with good accessibility.
  
• Clearance Angle: "C" suggests a 7-degree clearance angle, the smallest among these types, making WC inserts optimal for larger diameter bores where edge strength is prioritized.

---

VC Style Inserts

• Shape: "V" stands for a 35-degree diamond, providing a sharper point compared to broader angles, potentially offering better cutting precision and reduced cutting forces. This shape is suitable for detailed and fine machining tasks where precision is paramount.
• Clearance Angle: "C" with a 7-degree clearance angle offers minimal clearance, similar to WC inserts. This characteristic makes VC inserts well-suited for applications that benefit from a stronger cutting edge in larger diameter bores or where high precision is key.

---

Everede SCLPR Boring Bar

In summary, the choice between CD, TD, TP, and WC style inserts depends largely on the specific requirements of the machining operation, including the bore size, material hardness, and the desired balance between cutting edge strength and clearance angle.

CD and TD inserts, with their 15-degree clearance angle, are more suited to applications requiring a high degree of clearance to avoid dragging in smaller diameters.

In contrast, WC inserts, with their 6 cutting edges and 7-degree clearance angle, offer enhanced cutting edge strength for heavier cuts in larger diameters, although they provide less clearance.

TP inserts strike a balance with an 11-degree clearance angle, offering a compromise between clearance and edge strength.

As a final note, please keep in mind that Everede boring bars also often have the insert seated in a pocket that may enhance the clearance angle. For more information please contact Browne & Co to set up a call to answer your questions.