Small-Diameter Drilling Under Scrutiny

Today’s smooth-running high rpm spindles not only allow shops to cut faster with standard tool designs, they also unlock the potential of tiny tools. High spindle speed lets a small-diameter tool achieve an acceptable cutting speed in surface-feet-per-minute. It also allows a feed rate that is light in inches-per-tooth to be productive in terms of inches-per-minute.

That’s why cutting tool makers providing tooling for higher speed spindles are not just developing materials and coatings to cut effectively at high surface speeds, they are also developing more effective designs for small-diameter tools.

One supplier of small-diameter rotary tools is Kyocera (United States office in Mountain Home, North Carolina). Yoshihide Kojima is an engineer for that company. He says the dual requirements of strength from a small structure and chip removal from a small space lead to engineered features specific to small-diameter tools. A tour of one such tool—the 10 mm version of the company’s “Magic Drill” product—reveals various ways the tool differs from a standard-size drill.