Thread: Stropping with diamond paste after 4k?

I decided to try some diamond paste on a paddle strop before I get another stone. I've got paste from .25 to 9micron. Would I be right in thinking 5micron would be like using an 8k whetstone?

I fear using such coarse diamond stropping paste will cause issues down the road. You will probably severely convex the edge and impart deep stria that may lead to micro chipping. Get a proper 8k hone and avoid the grief. Keep the .25 mic if you wish, and leave the courser grit diamond for axes or knives.

Are you talking 5.0, .05 or .50um?

5.0um is about 3-4K, .50 is about 30k and .5 is crazy small.

Ken Schwartz is or was making a 0.015um diamond spray, rated or projected at. 1.2 million K grit.

8K equivalent would be about 2.0um.

Yes, you can strop on diamond or other aggressive paste or strays, and as said diamond can be aggressive. Additionally, not all diamond sprays and paste are the same in quality and results, Grit size, caret count and suspension all play a large part, in Nano grit performance.

Convexing a bevel is not a bad thing. Rounding an edge is from improper stropping.

From a 4k edge, strop/polish on a good metal polish to remove all visible stria, (Mothers/Maas, 100+ laps), then joint and re set the edge with the 4k or your highest grit stone with, the lightest amount of strokes possible.
Then polish on CBN .50 for a keen comfortable edge, (50+ laps). Diamonds will require experimentation.

Here is a good chart for CBN.

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 finish with .50 diamond after my 8k and 12k stone. That edge is wicked sharp but a little harsh so I will run it a few times over chromium oxide to lessen the bite.
Personally, I would not use a diamond compound over .5 for the scratching reasons listed above. Diamonds are a lot more aggressive than the abrasive compounds in the hones and stones used for razor honing. I do remember reading about someone who did an entire honing sequence using diamond paste and spray on strops, but I can't find it. If you do try to finish/hone with the variety of diamond compounds an important thing to remember is that you can never clean a compound off of a strop surface, so you need a new one for each grit.
By the way...9 micron diamond will put a terrific edge on a pocket knife so either way your purchase will not go to waste

Originally Posted by shaveuk

I decided to try some diamond paste on a paddle strop before I get another stone. I've got paste from .25 to 9micron. Would I be right in thinking 5micron would be like using an 8k whetstone?

How did it work out for you?

When I first started honing, I used a 1k, then a Norton 4/8, then I went to 1 micron diamond on leather, and ended with .5 micron CrOx. I still have a razor with that edge on it and it shaves wonderfully. I suggest getting an 8k at least. The diamond pastes can be aggressive, and do funny things to the edge. When I was using the 1 micron diamond paste, I did max 10 passes on each side. Same with the CrOx.

As I said, diamond quality and performance can vary wildly, but diamond spray and paste is deceptively aggressive, you don’t need a lot of laps or pressure to remove metal.

Some of Ken’s new Diamond emulsions are said to be less aggressive and leave a smooth shaving edge, though I have not tried them.

I do like and recommend CBN. You can go from an 8 or 12k edge to .50um very comfortably. If you need more keenness .125um is keener, but .10um is too much for me.

Isn't 0.5 microns what is needed to cut human hair ? does it mean that in order to pass HHT, 8K hone is not enough ??

Originally Posted by almond

Isn't 0.5 microns what is needed to cut human hair ? does it mean that in order to pass HHT, 8K hone is not enough ??

I think most people who are proficient at honing can cut hair after 1k.

I am specifically talking about HHT. Where you are not applying brute force pressure on the razor to cut a strand of hair. So looking at above table, you can cut hair with 15.0 microns sharpness ??