Thread: Is This Excessive?

I just wrote and asked them. They finished on a balsa strop with 0.25 micron CBN, which, by my reckoning is correct - 100,000k.

25um is about 60k. CBN on balsa can get aggressive and harsh. It is very easy to get an edge too keen. Smaller is not always better Comfort is the name of the game…

I like paper or cloth better for CBN. With nano grits, the substrate makes a big difference in performance.

Here is the CBN conversion chart.
Available CBN Abrasive Sizes from Ken Schwartz
Abrasive size in microns (μ) Grit Size (JNS)
80.0 #180
45.0 #320
30.0 #500
15.0 #1,000
4.0 #4,000
2.0 #8,000
1.5 (1 1/2) #12,000
1.0 #16,000
0.75 (3/4) #24,000
0.50 (1/2) #30,000
0.25 (1/4) #60,000
0.125 (1/8) #120,000
0.10 (1/10) #160,000

I've never used anything above a CrOx pasted paddle (roughly 30k, .5), I'm not sure you would actually feel any real difference going much higher

Oh yea, you will. .50UM is completely different than .50 Chrome Oxide, keener. .25 is smooth and keen .125 is a good maintenance paste from .50 and .10 is weeper keen, too sharp for me, like a brand new feather in an aggressive DE.

A lot depends on the substrate, leather is different than nylon, Linen, cloth or paper. And each blade will take a different edge. I shaved with 3 razors this morning, a wide,Joseph Elliot, full hollow Clauss and very hollow 6/8 Sheffield J. Pinder. All honed the same and stropped on .50 and .25um CBN, they all felt different.

I have never gone past .5, and don't really feel the need to since my shaves are good. I do want to try CBN though, diamond is a little harsh so I finish on CROX after diamond spray and that tends to tone it down a bit.

Originally Posted by puketui41

I just wrote and asked them. They finished on a balsa strop with 0.25 micron CBN, which, by my reckoning is correct - 100,000k.

This makes sense. Since everything was listed as "k" my brain just thought hones which did not seem logical. Had it been in microns it would have been obvious to me. Of course, changing unit of measure would be confusing to another reader.

So you want to talk excessive.

Take a good metal polish, Mass or Mothers, paint 3in X’s of either on the inside of a Cereal box cardboard. (By the way with Christmas here, save some of the thin, cheap wrapping boxes, they are larger than Cereal boxes and they make great strops for experimenting with paste.

Now take a razor up to a good finish quality edge, 8 or 12k, now do 50 laps on the pasted cardboard, you will remove all or most all the stria. Now finish, on your finish stone of choice. What you will have is a pure, whatever your stone of choice is edge. The metal paste edge is too rough to shave on but your finisher will clean it up, you may have to lightly joint the edge on the finish stone, depending on how aggressive you got with the paste.

You have to let the paste dry.

Save those boxes, they come in handy.

Excessive? Maybe a little…

Again, reality...

Yes, you can polish a bevel with ultra small grit CBN until you cannot see any scratches. It will look very impressive under a microscope.

Of course, the first time you shave or even strop, you will find that the scratches are back, the edges are slightly roughed up, and if you are lucky you will be right back to where you should have stopped in your progression in the first place.

Someone ought to save and frame this thread.

Around 10+ years ago if I had said there would be posts on all these Jnats and exotic hones out there folks would have said I was crazy.

Mark my word the day will come when guys will be using these crazy materials with super high grits.

I've honed/polished using the diamond and CBN pastes up to 100k and couldn't get a comfortable shave out of the crumbling edge. It does work well on heavier blades like hunting knifes, axes, lathe gouges, etc. , but for a razor or other thin edge the most I do is 50k diamond paste followed by 30k CrOx to smooth out the wire edge.