After almost 40 years of being involved with sharpening tools, the single most important issue that stands out is the expectation of how long a tool will keep running, and when to take it off for service.
It does not matter what kind of tool it is, or what you are cutting/machining – all tools will get dull and stop working effectively and efficiently. There are telltale signs – which are actually quite obvious – like burning, off-square cuts, or even sound changes. But I have found that with some operators, and in spite of these signs, they just push the tool harder to get the job finished despite the obvious fact that the tool is dull.
