Depending on what you need to cut, you might choose a razor blade or an iron wedge. This basic concept holds true in metalcutting. For a soft material, a sharp-edged cutting tool usually does the job. But when machining harder materials, a sharp edge can be a liability. Up-sharp edges on carbide, ceramic, polycrystalline diamond or polycrystalline cubic boron nitride cutting tools tend to chip, resulting in shorter tool life and poor surface finishes. In the early days of carbide tools, the solution was to round the edge with a hand hone to strengthen it. Those edge preparations were relatively crude. Today, cutting tool makers routinely apply hones from 0.003" (the diameter of a human hair) to 0.001" by a number of methods, including dry and wet blasting, slurry honing, tumbling and brush honing. Some are as small as 0.0003", while hones as large as 0.008" protect cutting edges when hogging.
展开▼
