>
> Well think about them from the front. You have the two blades meeting,
> the edges coming together from the diagonal corners, and a piece of paper
> between them. The paper wears just the edge as it slices through, soon
> as it is cut it seperates and has no strength. Sandpaper as it's cut
> will also be gouging out along the short face sharpening the edge. Open
> the scissors up, and try sandpaper then paper along the edge face to
> sharpen by hand, which takes longer? :)
But i cut two million (nearly) pieces of paper in normal operation compared
to 3 cuts in sandpaper.
> Aluminum is softer than steel, but there is still relative wear from
> friction, and aluminum is much tougher than paper. The part just ahead
> of the cut keeps the part just behind the cut together, if it wears the
> edge face a bit more than it wears the edge corner then it'll sharpen the
> scissors. Everything that you cut should either dull or sharpen the
> scissors, and it's an indicator of the relative wear of the corners and
> faces.
>
> Very similar to use of more complex machine tools. An expert machinist's
> tools rarely need sharpening. If you balance all of the variables well,
> you can actually sharpen the bits with the material being cut as they're
> used so that they stay sharp.
>
> Alan
>
Aluminium foil will carry aluminium oxyde, which is very hard.
Expert knife grinders use aluminium oxyde containing paint for the last
grinding.
As said, the next dull scissors will be experimented with.
Stefan