Asymmetric boring bar from Kennametal drives productivity

Kennametal´s new asymmetric line-boring solution increases machining robustness, process speeds, and bore quality, and reduces tool maintenance and handling.

Precision boring is a vital process in manufacturing many critical components. The accuracy and finish of a multi-journal crank bore in an engine block relates directly to power and fuel efficiency, and the time it takes relates directly to the engine company’s profits. Precision bores in numerous engineered components are essential to critical performance metrics. Such bores must meet critical tolerances; but the downside is that precision boring can be costly and time-consuming, with a small mistake or error resulting in the scrapping of expensive parts. The response from Kennametal is a geometric and asymmetric line boring bar solution being termed a revolution in the process by delighted users.


By definition, boring, as opposed to drilling, is a machining process in which internal diameters are made in true relation to the spindle centerline. This process is most commonly performed with the workpiece held stationary and the cutting tool both rotating and advancing into the workpiece, although boring is also done with the cutting tool and the workpiece being adjustable.

Common applications for boring include the enlarging or finishing of cored, pierced, or drilled holes and contoured internal surfaces. Related operations sometimes performed simultaneously with boring include turning, facing, chamfering, grooving, and threading.

Kennametal has released an asymmetric line boring solution that is said to accentuate the advantages of reaming and line boring, while virtually eliminating the disadvantages of both.

The Kennametal solution is set-up similar to a typical guide pad reamer, but the guide pad, normally located at 180° to the cutting edge, has been rotated. The resulting design provides sufficient freedom to enter and exit the guide part.

In short, this geometry means the bar can be fed through raw bores on an eccentric path. Kennametal says the solution retains all the advantages of previous line boring products, such as precision bore creation and support on both ends of the tool, but requires no expensive lift functions, obstructive counter-bearings or critical mechanisms inside the tool. The company also adds that complete feed-in and feed-out moves can be done at increased feed rates on conventional machining centres.

For further details contact Kennametal South Africa on TEL: 011 748 9300 or visit