There is an overriding misconception in the manufacturing universe that only manufacturers who perform high-speed cutting benefit from balancing their tools before putting them to work. The fact is anyone who cuts anything on a machine tool stands to benefit from the improved productivity and process reliability, and increased tool and spindle life that result from balancing.

The key for maximizing possible machine tool productivity is to have a truly balanced tool holder assembly (this assembly means toolholder, cutting tool, collet, pull-stud, etc.—all married together as an assembly exactly as it will be run in a machine tool spindle).

An unbalanced tool assembly, caused by uneven weight distribution, results in the following: vibrations that have adverse effects on the part being produced, the machine to be run at a less-than-optimum speed, decrease the life of the tool itself and is detrimental to the spindle. While it’s true that the negative effects of an unbalanced tool are more noticeable in higher-speed applications, they also can be seen with heavy tools and on those cutting tools with complex geometries. These negative effects may be more subtle at slower speeds, but are no less critical.

The centrifugal force caused by an unbalanced tool puts a strain on the spindle bearings, which reduces the spindle life by approximately 50 percent. The vibrations are transferred throughout the entire machine, and in particular the cutting tool, which can significantly shorten the cutting tool life. The tool life for an unbalanced toolholder assembly (toolholder with cutting tools, nuts, collets, screws, inserts, etc.) is shortened by 10 percent on average. The result is an increase in a shop’s day-to-day cutting tool costs.