When and at what grit to put in the micro / primary bevel?

[Rey HRH]

I apologize if I'm mixing up terms or if I'm obviously confused. If I'm confused about the terms I use in my question, I wouldn't mind being corrected.

Here's the question: assuming I want to put in a secondary / relief bevel combined with a micro / primary bevel, when in the process and at what starting grit do I put in the micro / primary bevel?

I forget where I read the idea but I like the sentiment that the coarsest stone stage is what makes the edge sharp (fully apexed, zero burr edge) and the succeeding grits are to refine the bevel (smoothing out the surface).

Given this, after I get the edge sharp at the coarsest stone (more acute angle), do I then put in the micro bevel (relatively obtuse angle), then refine the relief bevel with the finer stone (more acute angle), then put in the micro bevel again? This seems to be Murray Carter's method in his video. At both the coarse stone and the fine stone, he works the relief bevel, then puts in the cutting angle.

Or do I work the relief angle from coarse to fine, then go back and work the cutting edge / primary bevel / micro bevel on the course then fine? This doesn't make sense to me by the way but I'm just going through the different possibilities.

Or (assuming I have more than 2 grits of stones, do I work the relief bevel through the coarse, medium, fine first, then work the micro bevel on the last and finest grit only?

Or do I start first work on the relief angle only during the coarser stones then at some intermediate grit, do I start including the micro bevel?

If it matters, I'm thinking of having relief bevels at 2 degrees more acute than the primary / micro bevel that I want. For example, 13 dps relief for a 15 dps primary / micro bevel.

Thanks for your thoughts on this matter.

 

[awestib]

First, the definition of bevels is that it counts bevels in order of their deviation from the original flat plane or initial forged shape. That means that when you have your steel/blade before any grinding, the first bevel that deviates from the original is the primary bevel. That is most often the large bevel you see on a sabre grind for instance or the large bevel/"flat" that you see on a chef's knife. After that comes the secondary, maybe the tertiary etc. bevel. One of those is the cutting bevel as well, which contains/forms also the apex.

As far as micro bevel, you can do what ever you want. You use a coarse medium because you want to remove a lot of metal, if you don not have to remove a lot of metal, you can use a finer medium. This is always true with some deviation. For the most part, a micro bevel is exactly that, a very fine line, little surface area, very little material to take off. Therefore you would use a fine/your finest medium for this. However, it seems that there is some discussion whether you should "cut in" the Microbevel with a somewhat coarser stones and then polish that Microbevel as well with consecutive finer medium. At the end, the micro bevel gives you some more strength because it is more obtuse and lets you sharpen the very cutting bevel easier because it is very little material to be removed to form a new apex. That's it!

I would say the micro bevel needs to be as coarse or as fine as you want it to. If you need some "bite", stickiness, sawtoothness to the apex, keep at at a lower grit. If you need a very high polished smooth edge, use a higher grit.

Most of us I believe would create the cutting bevel first to the grit desired and then add the Microbevel.

 

[calc]

For the most part, a micro bevel is exactly that, a very fine line, little surface area, very little material to take off. Therefore you would use a fine/your finest medium for this. However, it seems that there is some discussion whether you should "cut in" the Microbevel with a somewhat coarser stones and then polish that Microbevel as well with consecutive finer medium.

This is my process, and it really depends on the steel. If it's a softer steel, such as 1095, I'll sharpen at a DMT C/F/EF, then microbevel with a Spyderco UF rod. If it's a more wear resistant steel, e.g., ZDP-189, I'll sharpen at a C/F/EF, maybe back up to a F/EF for the microbevel, then polish with the UF rod.

 

[Rey HRH]

Thank you both as you confirmed what I thought made sense except I wasn't certain so I asked. Actually, I totally didn't know which way to go.

Also, I didn't want to just dismiss Carter's methodology if there was something I was missing.