ISTM there are several issues of concern here, and I continue to communicate with Jaxman.
Visible machining marks, perhaps suggestive of worn tooling, should not, in themselves, affect the flatness of the pill.
But I agree, are undesirable.
But before crying “foul” about the flatness, it is also necessary to be sure that the MCPCB is also perfectly flat.
It is not unknown for these to be a little dished, hence the perfectionists who “lap” them using e.g. fine grit or abrasive paper, on e.g. a piece of float glass.
This is easily checked, e.g. put them down on a flat piece of glass, e.g. float glass, or a mirror, and see if they rock (convex bottom surface).
To test for concave bottom surface, you could use “engineer’s blue” or simply felt pen ink, to determine where physical contact is present, or absent.
I would also suggest, that some basic checks of pill flatness be performed, before declaring it bad.
As simple as offering up e.g. the end of a steel ruler to the surface.
Or better, break a razor blade to size, and offer the edge up.
If the pill turns out not to be sufficiently flat, simple circular grinding or lapping will not improve it. In fact will tend to make it more convex.
TBH, the approach suggested, careful application of a graver, wrapped in abrasive paper, with some sensitivity, would probably be the best approach.
Having served an apprenticeship that included scraping surface tables flat, to within a few wavelengths of light, I would have no problem in truing up any such minor imperfection.
And then, there is the question as to how important this is, in reality. Mirror finished, absolutely flat to the level that Newton’s rings are formed ?
I see this sort of work as the difference between a mass-produced mainstream item, and a hand-finished offering, that takes things to the next level.
I am encouraged that Jaxman take this much care with their standard products, and have operators who can take the initiative to correct any such minor imperfections.
I hope that we can try to reach the same standards.
