Edge Anatomy Question.

Steel130 · Apr 23, 2012

Ok so basically I am wondering. When I get a knife from Spyderco ( just an example ) I sharpen it up on the sharpmaker. Now when it is sharpened this way there is no nice shiny bevel is is just sharp with the belt looking finish above the edge. So if I sharpen the edge on the 40* setting does this mean I have a 20* primary edge with a back bevel ( or secondary edge ) with a degree setting of whatever Spyderco sharpened my knife too? Now if I do a complete reprofile of the edge I get a nice shiny bevel, does this mean I have sharpened the edge to one primary edge with just a shoulder above it? This being the flat of the grind? To make my thoughts clearer I have made two pictures to help clarify. Also if someone could help make sure my terms are correct that would be great.
What I think my edge looks like after I have sharpened a Spyderco factory edge:

What I think the edge looks like after I totally reprofile at a 30* setting excluding human error:

BITEME · Apr 23, 2012

Correct

Obsessed with Edges · Apr 23, 2012

You've got the idea. Assuming Spyderco's factory edge is at 30 degrees inclusive (15 per side), using the Sharpmaker at the 40 setting will produce a 20-per-side secondary (or micro) bevel, as illustrated in your first pic. Reprofiling on the 30 setting will do as your 2nd pic illustrates, putting a 15-per-side primary bevel on the edge, with a 'zero edge' (no secondary or micro bevel).

Jason B. · Apr 23, 2012

Yes.

The 40/30 settings of the SM are inclusive number meaning it will be half per side of the blade. So per side it would be 20/15.

Steel130 · Apr 23, 2012

Thanks guys.

RevDevil · Apr 23, 2012

Mirror edges are nice, but they don't do much of the cutting. The very edge is the most important part. Watch the video that comes with the Sharpmaker, it has a ton of information.

Steel130 · Apr 23, 2012

RevDevil said:
Mirror edges are nice, but they don't do much of the cutting. The very edge is the most important part. Watch the video that comes with the Sharpmaker, it has a ton of information.

Thanks. I'm pretty solid around using the sharpmaker

I was more curious as to the micro view part that I couldn't see.

bdmicarta · Apr 24, 2012

Steel130 said:
Thanks. I'm pretty solid around using the sharpmaker I was more curious as to the micro view part that I couldn't see.

You can see it a little better with a good magnifier.

Also you can put a bit of black ink on the edge with a Sharpie pen before you start sharpening and then you can see how much of this black is removed by the stones.

bgentry · Apr 24, 2012

Steel130 said:
I was more curious as to the micro view part that I couldn't see.

Reflected light will let you see a lot of things you can't easily discern with the naked eye and normal lighting alone. Angle the blade back and forth under a strong light and watch the reflections on the blade. If you have a microbevel at the edge, you will *definitely* see it as a thin reflection running the entire length of the edge.

I wish I'd learned this lesson MUCH sooner.

Brian.