5 Considerations for Boring Tool Selection

Boring can be tricky business—with several variables that can impact performance. And as with many things metal cutting-related, many boring issues can be solved with tooling troubleshooting (from too-long cycle times to compromised tool life to poor part quality). Furthermore, skimping on boring tools and accessories can cost more in the long run—resulting in the aforementioned problems. Read on for five important considerations to keep in mind when selecting boring tools and accessories.

1. Consider modular boring systems

Modular tool systems allow shops to create tool assemblies for specific applications quickly and easily—without the need for new specialized tooling and tool holders. This is helpful in challenging boring applications because it allows machinists to troubleshoot with the components they have on hand. This flexibility (plus quick and easy changeouts) greatly reduces setup and engineering time. Keep in mind: Modular boring assemblies should always be as short as possible to reduce vibration. We recommend modular boring assemblies contain no more than five components (ideally four or fewer), not including boring head insert holders.

2. Leverage digital boring heads for improved performance

Digital boring heads display setup measurements on a small readout right on the tool. This allows for much faster, more streamlined precision adjustments (bluetooth-enabled versions allow for even more efficiency). But perhaps most importantly, this technology can greatly improve performance and eliminate costs related to test cuts and scrapped parts.

Digital boring heads have the most impact in applications that call for tight tolerances or difficult-to-machine materials. In fact, some digital boring heads have adjustment increments as fine as 50 millionths of an inch in diameter.

3. Think about vibration resistance 

Vibration can wreak havoc on boring operations—impeding speeds and feeds, cutting tool life short and diminishing the quality of the finished part. Preventing vibration through tooling selection is a two-fold process: 1) Select the largest possible diameter and minimum possible length for your boring assembly and 2) Consider licensed, dual-contact tooling.

Dual-contact holders provide simultaneous contact between the machine spindle and the holder’s taper and flange. This clean mating of the tool holder and spindle greatly increases rigidity to reduce vibration. But buyer beware: only choose dual-contact holders that are licensed for your machine spindle. Non-licensed tool holder manufacturers do not have the critical specifications necessary to make true dual-contact holders. The result, at the least, is less than ideal boring performance; at worst, you could damage your machine’s spindle.

4. Look into twin boring cutters 

When it comes to making holes at volume, balancing speed with performance can be challenging. A common answer is often helical interpolation with a mill for roughing out holes. But twin boring cutters offer an alternative to helical interpolation milling that has several advantages.

For one, twin boring cutters for roughing operations offer greater simplicity: They require only one setup, with no specialized equipment and less programming than helical interpolation. Performance is better as well, with superior load balance in the cut for more reliable and consistent performance; and better chip evacuation (thanks to smaller chips). Finally, the plunging motion of twin boring results in axial load rather than radial, which better preserves machine and spindle components.

5. Remember the importance of insert grades and geometries 

Optimize your boring applications with the ideal insert grades and geometries. It may seem like metal cutting 101, but sometimes the details get lost in the shuffle.  

Some general tips:

• Pressed geometry inserts are typically longer-lasting (in stable conditions), but the radial cut depth should be at least one-half of the insert’s nose radius.
• Look for inserts with ground geometry as they are ideal for deep or long-reach bores, long-chipping materials and instability issues.
• Stay on top of the latest insert grades and coatings available—there’s always something new to help maximize performance.

Regardless of how simple or complex your boring application is, it pays to have a wide variety of options and expert guidance when challenges arise. Make sure your tooling provider is up to the challenge.