The faceted edge?

[Fred.Rowe]

The straight knife I carry on my hip all week, is .20 through the spine at the plunge lines. A fairly thick cross section. The original secondary bevel was ground at 24 inclusive; but since I use this knife all week long, the edge dulls a little by Wednesday. I have gotten in the habit of setting my Wednesday touch up angle at 28 degrees, my Friday touch up angle at 30 degrees inclusive and my Sunday touch up at 32 degrees.On Monday I re-grind the edge to the original 24 inclusive angle. This routine saves me both time and steel. I lose less steel overall and maintain an excellent edge with good shoulder width behind the edge for strength. I don't believe micro bevel is the correct name for this grind; faceted edge sounds more reasonable since the edge is a compilation of all the angles used to touch up the edge.

 

[awestib]

Micro bevel on micro bevel you could say. I think for a knife type like this one (compared to a scandi grind), it makes sense, since you probably don't loose much cutting performance and "regrinding" it to the original bevel angle is not too big a deal.

How thick is the primary ground before secondary cutting bevel Fred? I can't really tell from the picture but it seems nice and thin! I am always amazed when I see a we'll build knife where you usually can not !! or almost not see the cutting bevel compared to "pry bars" where the secondary bevel looks wide. On that note (getting carried away here a bit), practically it does not seem to be a big deal but theoretically the primary grind is being neglected by most, for cosmetic reasons often I think. It is actually quite interesting to maintain the primary bevel right from the get go, you see how uneven most bevels actually are and how nicely flat and even they become after a while of doing it. In my believe and in some here on BF the primary bevel should be maintained every or every other sharpening session, that way I keep the geometry nice and thin.

 

[HeavyHanded]

Is an interesting maintenance scheme, and probably very well suited for to the ERU.

I'm with Andy on maintaining the primary grind often. In general I only use a single cutting bevel, if the edge needs to be tougher for a given task I'll convex it a bit or increase the inclusive and maintain there - no micro bevels of any kind. But then that works well with my Washboard, so we all more or less adopt strategies that work with our favorite tools maybe. Plenty of wiggle room so many strategies probably about equal over the long haul.

That is a beautiful EDC, I'd be looking for excuses to cut stuff all the time...

 

[KennyB]

John Juranitch actually advocates this type of "compound" beveling. As you guys mention, people neglect the need to thin out the primary angle--and like awestib said mostly for cosmetic reasons. So what he suggests is to grind in a "relief" angle that is at a very acute angle--clost to 10 per side, just barely above the actual blade grind in most cases. The real reason he advocates this "relief" grind is that if the user was just grinding on the same cutting-edge angle on top of say a full-flat blade grind, then over time the metal being removed at the same angle will just travel laterally up the blade, narrowing it up from edge to spine. The other effect of this is that it is also getting thicker behind the cutting edge over time. So that's why when you see an over-sharpened knife, it looks like someone was trying to make a really thick fillet knife

But anyway, the "relief" grind keeps the stock thin behind the edge, and then having the cutting-edge angle on top of that relief grind means you can just keep grinding on the same angle for quite a while and not worry about the actual blade stock getting too thick. Sooner or later you will gradually blend it over the relief grind, but then one just grinds on the relief grind again ( keeping the stock thin ) and can put back on whatever cutting-edge angle they want. The interesting thing is that Juranitch even suggests adding other additional bevels as you're mentioning. Lot of people say he's talking about microbeveling because it sounds like it, but as you're saying it's more like multi-faceted or compound bevels.

He also says that just sacrificing the "prettiness" of the edge and grinding on the primary blade grind itself is the best though. It's a pretty cool book, worth a read, although his views on things are pretty contrarian.

I do pretty similar to what you're talking about actually, but I have a pretty unorthodox method. I basically look down the surface of a hone, and then actually visually inspect the flushness of the bevel an apex of a knife edge to the hone in front of my face. It's pretttty awkward but man there is just no matching the type of control I get over it in terms of just refining the edge. It's also really quick when it comes to just maintenancing though, beacuse if I hold the edge perfectly flush with the hone, and then just by feel notch it up a little bit I can put in a tiny little microbevel. LIke you said I just do that each time the edges needs it until ultimately I have to grind in the overall edge angle again. Probably why my edges come out looking pretty convex.

You can spot what I'm talking about here if you look closely at the belly mid-way between tip and heel.

 

[kniferbro]

I always think of this as a 'compound convex' edge. Like how a circle is made up of an infinite number of angles, so is a convex edge, except in your case there are only 3 but you are achieving near the same effect.

 

[Fred.Rowe]

Micro bevel on micro bevel you could say. I think for a knife type like this one (compared to a scandi grind), it makes sense, since you probably don't loose much cutting performance and "regrinding" it to the original bevel angle is not too big a deal.

How thick is the primary ground before secondary cutting bevel Fred? I can't really tell from the picture but it seems nice and thin! I am always amazed when I see a we'll build knife where you usually can not !! or almost not see the cutting bevel compared to "pry bars" where the secondary bevel looks wide. On that note (getting carried away here a bit), practically it does not seem to be a big deal but theoretically the primary grind is being neglected by most, for cosmetic reasons often I think. It is actually quite interesting to maintain the primary bevel right from the get go, you see how uneven most bevels actually are and how nicely flat and even they become after a while of doing it. In my believe and in some here on BF the primary bevel should be maintained every or every other sharpening session, that way I keep the geometry nice and thin.

It was intended as a zero edge when the original bevels were ground; I finish most all blades with a 12" flat bar with sticky 80--120--220. I'm of the mind that if you put the work in here, on the primary bevels, the edge itself, will have broad possibilities.
I agree its important to have a base line angle to work with. With this knife, I'm always aware, no matter what the apex is "tuned" to 30 -32 for example, its being carried by the 24 degree wedge of steel. I'm in the position that if the edge loses that baseline angle I can regrind it on the 2 x 72, using a Bubble Jig, to a near perfect 24 degrees.

It is amazing the condition a cutting edge can get to. I'm seen them in all configurations; mostly its different grinds on opposite sides of the blade. Hollow grinds are easy to get miss aligned; wrong radii. I get knives through here, the only way they can be made sharp is to start over at 120 grit.

Keep your primary thin, Fred