The Drilling and Tapping Characteristics of MX-2 Alloy Steel Hardened to 50-56 Rc

Results are reported of drilling and tapping tests on the high cobalt alloy steel, MX-2, hardened to 50-56 Rockwell C. The empirical data are presented and discussed, and conclusions are drawn as to best shop practice. 52 Rc has been found to be a nominal upper limit to the use of steel cutting tools. At and below this limit, this material may be drilled readily and tapped under appropriate cutting conditions; above 52 Rc, special procedures are required to attain adequate life from high-speed steel tools.