How To Select the Correct Tool Holder for Your Insert

Selecting the right tool holder is a critical step to ensure optimal performance and productivity within your machining operations. The tool holder not only secures the insert but also plays a crucial role in maintaining rigidity, and influencing the overall stability of the cutting process.

The first consideration when selecting a tool holder is whether you are performing external or internal turning operations. For external features, you will typically require a square shank tool holder for maximum stability. While internal bores call for a round shank tool holder otherwise known as a boring bar for clearance. 

The shank size of external square tool holders will depend on the specifications of your particular machine tool. For internal turning, the shank diameter is dictated by the minimum size of the bore diameter of your workpiece, as well as any limitations imposed by your machine's tool turret or tool post. 

Turning tool holders come in left-hand, right-hand or sometimes even neutral orientations. The hand of the tool refers to the position of the insert relative to the tool holder itself. When the tool holder is placed in the machine's turret or tool post on your lathe, matching the correct orientation of the tool holder is essential. The insert must cut on the machine's centre line providing the correct clearances and also provides access to the workpiece. 

Another key consideration is the geometry of the insert you will be using, various tool holders are available to accommodate positive or negative insert geometries. 

Negative inserts typically have twice the number of cutting edges compared to positive inserts, this is due to having cutting edges on both sides of the insert. This can improve cost efficiency by doubling the inserts tool life. However, negative inserts generally require more increased cutting forces which then generates vibration, which may be a concern for certain applications. 

Positive inserts, on the other hand, have a single-sided sharper cutting edge. They tend to cut through the material more effectively, making them a better choice for machining bores or thin walls where reducing vibrations is critical. 

Fortunately, if you can't find the exact tool holder you need, as there are hundreds of different combinations currently on the market, the new MSC Edge inserts are designed to fit industry-standard ISO tool holders. This provides you with greater flexibility to utilise your existing tool holder inventory. 

By understanding key factors involved in the tool holder selection, such as the turning operation, shank size, hand of the tool and the insert geometry. You can make an informed choice that optimises your machining performance, productivity and part quality. Remember to also consider the compatibility of your ISO tool holders with the ISO inserts you plan to use, such as the versatile MSC Edge line, to ensure a seamless and efficient machining process. 

For more tips and insights on machining tools and techniques, stay tuned to our blog, instagram or explore MSC Edge’s comprehensive range of turning inserts today!