I know people spend hours agonizing over 1000ths of an inch, setting up jigs and dial indicators and those method WILL provide better results. What about if you don't have those tools? What about if the machine simply needs to be sharpened and put back into service now, today. Well my method works, it can be done in the field with little more than a scrap and the results are not that different. I call it the law of diminishing knife return, 500% more effort for 10% better results. I do not mean to disparage the efforts of those striving for absolute perfection simply to say that it isn't always needed or efficient.