Proper grit progression for polished edges?

bpeezer

bpeezer

Joined
Jan 27, 2013
Messages
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I finally got a 60x magnification lighted loupe to diagnose some of my sharpening inconsistencies. I already knew that part of my problem with high polished edges was improper grit progression. I skip straight from 3k to 0.5 micron :o I've known this was a problem and I know why it's a problem, so no need to go into that.

I just need to know roughly what grits to go to between 3k and 0.5 micron, and what stones you would recommend. I'm used to relatively hard water stones, so I was considering maybe a couple of Shapton Glass stones, but based on other recommendations I've seen I'm also considering Arashiyama or Nubatama Bamboo stones. I believe a 6k or 8k will work well after the 3k, but what comes next?

For reference, here are some of the edges that are motivating me to spend more money on stones.

8_Cr13_Mo_V_Scratches.jpg

8Cr13MoV Kershaw Cryo

154_CM_Scratches.jpg

154CM Benchmade 300SN
 
Sharpening to 3k grit can give you an amazingly sharp edge; and your edge looks sharp from what I can see, unless you just want a more mirrored look to the edge.

I go from 1600 grit to the .5 micron stropping. That's not mirrored territory, but it is incredibly sharp. I'd worry more about your grit progression before the 3k rather than after it. You may be experiencing wobble stack from freehand sharpening with a long progression of different grits. Some people can hold a fairly consistent angle when shifting from one grit to another, each with a different feel. I can't, so I use a guided system (Wicked Edge).
 
Sharpness isn't the issue, I don't have a problem whittling hair or push cutting pretty much anything. I just want that more attractive mirror look :D
 
For a true mirror finish it usually starts around 8k-15k JIS depending on the stone and steel formulation.
 
No, 3k is an appropriate grit to make the jump to the 5-8k range. If you were sharpening chisels or japanese single bevels you might want a tighter grit progression, but the narrow edges on western knives let you skip around more.
 
I used DMT EF, 1000 and 1500 grit sandpaper plus stropping (balance strop) to this edge 8Cr13MoV EL02:
8993171613_47a4558e36_b.jpg

Hair splitting
8994420436_c0782dbb4c_b.jpg

Not sure what is the comparison of DMT EF to your 3k. The balance strop is about 10-14 micron guessed by bluntcut.

The Resilience didn't go through sandpaper, only EF and strop:
9054645951_22df1b9ac0_b.jpg

Hair splitting too.
Performance, it's great. Looks, not really mirror.
 
Thanks for the pictures Chris! Your edge looks very highly polished for 10 micron, and I think that proves that I'm not polishing my bevels enough to really take advantage of the .5 micron paste.

Here is the Cryo, as you can see the bevel looks a little cloudy and dark.
Cryo_Mirror_2.jpg
 
If you're looking for the bright finish on stainless, it's probably best to avoid the japanese stones that try to simulate "natural" japanese stone finishes (many of the nubatama bamboos do this), as they tend to produce a dark mirror haze on stainless steels. The japanese stones that leave "synthetic" finishes, like shaptons will give you that bright mirror look
 
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To clarify, the bigger the grit jumps, the more work/elbow grease is needed when working with higher grit abrasive. Example of the Resilience (used rarely) compared to the EL02 (used often, strop often) is that more work result in smoother finish.

Please also bear in mind that it is also possible that the HT on the Resilience is better, so polishing it after DMT EF is more difficult (diamond tends to dig deep into a lower less carbide steel like 8Cr, or at least that's what forum members said, I haven't had chance tesing better steel) resulting in hazed mirror compared to EL02.
 
Thanks for the thoughts, maybe I'll pick up a shapton and put some hard work into it. To add some food for thought, a friend gave me a nicely polished convex edge on a couple of knives.

Convex_Tanto.jpg


And no, he didn't use a dremel. That just happened to be nearby when I wanted to take the picture :D
 
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