I just made an experience, I'd liked to share with other listlers. It might sound silly, however, it's not o-tone Harpie.
I repeatedly mentioned the translucent or the light in general as one of the most excellent measuring devices. It shows deviations of tolerances or sizes of fractions of mm or inches down to amazing ranges.
I was just going to make an extreme sharp tool for smoothening harp chambers and used the steel handle of a file broken apart accidentally.
While I was grinding the part, it came into my mind how I can be sure that I achieved the uttermost sharpness. Yup, it's the light coming from the lamp of my "workshop".
If you see the slightest light reflection when looking down to the cutting tip, you can be sure that you haven't got the optimal sharpness. OTOH, if the tip doesn't show a reflection any more, you did it.
