George wrote:
"Mark Fitzsimmons" wrote in message
ups.com...

mac davis wrote:
Honing is only effective if the tool is pretty sharp already.. otherwise,
you're
not honing an edge, you're polishing it and it looks pretty, but is also
pretty
dull...

Yeah, what he said. When you look at the edge in with light shining
from behind your head, and you can see a shiny metal line where the
edge is, that means it's dull, because the light is reflecting off a
radius. When it's really sharp, the edge is so fine you should be hard
pressed to see any line of reflected light on the edge.


Hmm- this pertains to non-hollow ground edges? A hollow ground edge always
shows a shiny line at edge and heel. Of course even a non-hollow ground
edge can shine if you've changed the sharpness angle. They call it a
"microbevel."

No, hollow ground. I'm talking about looking at it from the angle that
bisects the angle of the cutting edge, not looking at the bevel
straight on. Any edge, if sharp, the shiny line should be nearly
invisible. You want to sharpen until the shiny line (radiused edge)
disappears. If light reflects off the "edge" back into your eye when
the edge is pointed at your eye, that means there is metal that is
parallel to your eye, in other words, not aligned with either the bevel
or the tool surface, in other words, not sharp.

I mean point the tool at your eye periodically while you're turning:
eye ball ) edge points at the eye
and a shiny line will indicate the tool is getting dull. the line will
get smaller and disappear as you hone, If the radius is really bad,
like from super hard wood, you might grind until the shiny line
disappears then hone, but sometimes just a few strokes with the stone
is enough without the grinder. Or if the grind is coarse, you'll see a
crooked line that gets straighter as you hone.

George is talking about this viewing angle:
eye ball ) /\ bevel
and then you'll see much wider shiny lines at the edge and heel of the
hollow ground, which get wider as you hone.