Primary edge or micro bevel

[jzmtl]

This is how I always envisioned it.

[The Deacon]

This is how I always envisioned it.

Exactly. And to take it a step further, the angle of the blade will be either 0º or the same as the primary grind, for flat grinds the angle of the primaary grind will be shallower than that of the secondary grind, and the angle of the secondary grind will be shallower than that of the micro bevel, if there is one.

But, at the risk of confusing things again, the only grind/bevel that's absolutely necessary is the primary. If it goes all the way to the edge you have either "zero edge" full flat grind or a scandi (zero edge saber) grind.

[jackknifeh]

This is how I always envisioned it.

Thank you!

Is a picture worth a thousand words? I think so. This is just what we needed for this thread. The terminology I've used is reversed compared to what I've used. I called the primary bevel the cutting edge and the secondary bevel is the thinned area of the blade. It doesn't matter though. I'd rather know of a standard so it's easier to communicate to others.

So, in the picture what would be the benefit of a micro bevel? That's what I really wanted to know in the beginning.

Jack

[wongKI]

Increased edge toughness, without losing much cutting performance.

This is good for both "knuckle-draggers" and "dark-siders". Those who like hard use blades with tough edges can put on a secondary (or even a convex; convex is really infinite secondary/tertiary/quaternary etc bevels) to improve toughness by increasing the amount of steel behind the edge.

For a thin edge lover, a micro allows you to take the primary grind even thinner before the edge starts to fail. The micro doesn't affect cutting performance much (if at all) and greatly improves toughness.

For an example you can take a look at Unit's Caly 3. He thinned and reground it to the point of chipping-then after the microbevel it was fine.

[jackknifeh]

Increased edge toughness, without losing much cutting performance.

This is good for both "knuckle-draggers" and "dark-siders". Those who like hard use blades with tough edges can put on a secondary (or even a convex; convex is really infinite secondary/tertiary/quaternary etc bevels) to improve toughness by increasing the amount of steel behind the edge.

For a thin edge lover, a micro allows you to take the primary grind even thinner before the edge starts to fail. The micro doesn't affect cutting performance much (if at all) and greatly improves toughness.

For an example you can take a look at Unit's Caly 3. He thinned and reground it to the point of chipping-then after the microbevel it was fine.

That's the kind of info I was looking for. That is the cake. Thanks. The issue of terminology is very good icing as well.

Jack

[jzmtl]

Plus it's easier to sharpen a microbevel than the entire edge, less metal to remove.

[The Deacon]

Plus it's easier to sharpen a microbevel than the entire edge, less metal to remove.

True, but you can only get away with that so many times before you've created a thick, obtuse, edge that doesn't really cut very well.

[pleeho]

....Leonard Lee reverses these definitions (p.16 The Complete Guide to Sharpening, 1995), and I believe this is the current convention: that is, the primary angle is the main grind, then the secondary angle is the "micro"beveled point of contact or the tip. That is, "Spyderco puts a 40degree primary edge on the blade, then grinds the tip to the 30degree secondary edge."

This is confusing, but I think you have it backwards (perhaps it is just me)?

The bevel farthest from the spine of the knife will have a LARGER degree angle than any "back" bevel. Said another way the bevels found closer to the spine will be either the same as the edge or LOWER angle (assuming some variation of flat grinding is used)

Yes I meant the lower angle for the primary, the higher angle for the secondary - this is what happens when you get older and the mind goes.