1.5K ~ 3K / 16K Edge Leading Edge hmmmmm

[branwell]

Been playing with some edges and really like this one.

While finishing with edge trailing leaves a super keen edge, its really challenging to do it where there is no semblance of a wire edge giving the knife a very sharp initial feel that drops of quickly.
A solution to burrs and wires is to finish edge leading but by comparison, edge trailing is just so much keener its hard to give it up.

Hybrid edges. So I've been playing with hybrid edges for years and really like them. This is the sharpen normally on a 1K ish stone and strop to finish on something finer like a 6K. You get much of the toothy bite of the 1K but a lot keener.

The edge I propose here is a hybrid of sorts but with a difference. The sharpening stone can be as low as a 1.5K or as high as a 3K and the finisher a 16k. The technique is different as well.

On the low stone, sharpen as usual and do your best to get rid of the burr when you finish. For me, doing some light edge leading, a couple wood drags, a little more edge leading, then some light edge trailing to keen things up works pretty well.
Next, take out a 16K and do some edge leading strokes checking the edge ( I use a tomato ) as you go till you reach the level of keenness you are after.

Why not start on the 1K like a normal hybrid? You definitely can but 1K is normally always too toothy so you have a go a ways to get it chilled out. Starting in the 1.5K to 3K range is just a better start point as there is less work on the high grit side.

Could you use edge leading on a 6K as a finisher? Sure, but the 16K is better. The issue is that edge leading just isn't as keen as edge trailing but by going way up in grit, you can address much of that.

The finisher I've been using here is the Shapton Glass 16k. Being a hard stone that doesn't release much abrasives, its pretty well suited for edge leading finishing. Others would work, but muddy stones or stones that release a lot of abrasive tend to not be the best when it comes to finishing edge leading. Your mileage may vary.

Anyways, fun edge. Something to try if you have some high grit stones collecting dust.

 

[Vdark]

Do you have any input on "refreshing" the edge on high grit stones kind of like how some softer steels can get some life back from a honing rod? Or do prefer going lower and back up or?

 

[branwell]

Do you have any input on "refreshing" the edge on high grit stones kind of like how some softer steels can get some life back from a honing rod? Or do prefer going lower and back up or?

I don't let my knives get dull so for me refreshing is a few swipes on whatever finisher will provide the edge I'm after.
At the moment the finishers I really like are the Suehiro Ouka 3k, King 8K Gold, and the Shapton Glass 16k.

If its a hybrid edge, I might drop back to the foundation stone just enough to get the tooth back and then finish on the finisher.

 

[branwell]

BTW, for those of you that have them, the Nubatama 1.5k Platinum is a phenomenal foundation edge for the above mentioned technique. I suspect the King 1.5k whose edge is similar to the NBP 1.5k would be amazing as well. Its literally 4 or 5 light swipes per side on the 16k. Very fast edge to produce.

 

[Rangen]

I agree, this works great. I do it too from time to time, and I would do it all the time if I didn't have some JNats that produce my favorite edges.

The SG 30K is even better than the 16K. Gets the burr off and does hardly anything to the underlying edge.

 

[M1k3]

I've done 120 > 10k progression. Works pretty good. Generally do 500 > 4k though.

 

[Steampunk]

I love reading about this sort of testing! Great post.

 

[branwell]

Hmmmm. Don't know why I didn't think of this but a guy on insta asked if this would work with Coticule's.

I tried it with a Belgian Blue and a Meara and while slower than the Shapton 16K, the edge came out really well. Super keen with a ton of bite.

Am glad about this because using the normal method, I was having to use Aoto slurry on those stones to like them with kitchen edges and even then, it took a fair amount of effort to find the balance.

 

[DaM0w]

In this process you’re testing and in your normal go to sharpening sessions are you stropping on any leather or felt material after the finishing stones or using them as a way of avoiding that step

 

[branwell]

In this process you’re testing and in your normal go to sharpening sessions are you stropping on any leather or felt material after the finishing stones or using them as a way of avoiding that step

In my normal sharpening for my own knives I normally touch up on the finisher, either an Ouka or King 8K and don't strop. Strops for me leave an edge that just doesn't feel right. I cant explain it other than it doesn't feel right in the cut. Yes very sharp, but the feeling ( For strops I've tried hanging leather, denim, linen. Also tried Balsa, leather on glass and pretty much every permutation. Used CBN and Diamonds from 3 to .5 micron.)

If I'm into hybrid edges which I often am, I'll take a couple strokes on the foundation stone and then a few edge trailing strokes on the finisher.

 

[branwell]

For those of you who where interested in this technique, I've tried a bunch of variations and here are the findings.

The technique is really pretty remarkable in its flexibility for the low grit base stone.
On the other hand, its pretty inflexible on the high side.

On the low side I tried the Shapton Pro 220, DMT 320, Nubatama 400, Chosera 400, DMT 600, Geshin 600, Carter Pride 600, King 800, Chosera 800, King 1K, Shapton Glass 1k, Nubatama Ume 1k, Nubatama Platinum 1K, DMT 1200, Bestor 1.2k, King 1.2k, Nubatama 1.5k, Shapton Glass 2k, Naniwa Pro 2k, Shehiro Ouka 3k.

On the high side I tried the Nubatama Bamboo 5k, Geshin 5k, Ariahama 6k, King 6k, Shapton Glass 6k, King 8k, DMT 8K, Shapton Glass 16k and a couple naturals including a Belgian Blue, a Meara, and several unidentified.

As a refresher, what we are doing here is sharpening as normal on the low stone and leaving as clean an edge as we can by finishing up using light strokes including several edge leading and wood drags to deburr. After that we are using light edge leading strokes only on the high grit stone. ( This differs from a traditional hybrid edge where we strop or do edge trailing on the hi grit stone ) The goal is an edge that is both keen af, has bite, and is not prone to subtle or not so subtle burr issues.

Lets start on the high end.
The Shapton Glass 16k was easily the stone of choice. It was quick and the resulting edge was sharp af. The Naturals did well as well, especially the Belgian Blue but where noticeably slower. The edge the naturals left did not have any advantage I could feel.
All of the other high grit finishers worked to varying degrees but none where even in the same ball park as the 16K and the naturals. Will discuss why in a minute.

On the low end there was much more flexibility. Using 600 to 1.5K as a base produced really good results. This was surprising to me on two fronts.
First was the range. With traditional hybrid edges, I find much under 1K to be too saw like and much above 1.5K to be too muted.
Second is bite feel. I am very partial to using the Nubatama Platinum 1K or King 1K as a base stone. They leave just the right amount of and type of bite to refine stropping on the 4K ~ 8k stones. Stones like the Chosera 800 by comparison left bite that is too muted. Stones like the Nubatama Ume 1k or Bestor 1.2k to aggressive.

With the edge leading technique on the Shapton Glass 16k, the bite side of life felt just right no matter the base stone as long as it was in the 600 to 1.5k range. Will discuss why in a minute.

Drooping down to the 220 range as a base didn't work. The type of bite it left didn't feel right. Going above 1.5k and things get too muted.

Now to the why of things ( and I am guessing and making a lot of assumptions here. I could be totally wrong and am open to being told as much)

Edge leading works by not only abrading steel on the bevel, but also by micro chipping the leading edge of the edge.
This is fundamentally different to edge trailing which abrades steel on the bevel but does not micro chip the edge.
All this can be seen in SEM images. scienceofsharp has lots of nice pics of this process.

Why is the Shapton Glass 16K so much better than the other finishers I listed?
I don't know for sure but I suspect the following in no particular order.

Edge leading chips the leading edge of the edge. Edge trailing does not. This results in an edge that is not as keen as an edge trailing edge for the same grit. Basically, and I don't know if the ratios are right, but a raggedy rule of thumb might be half. So if you wanted a typical 8K edge, using an edge leading technique you would need to use a 16k stone.

The Shapton Glass is also a hard stone that doesn't shed much abrasive. This chips the edge in a different way to a softer stone shedding a lot of abrasive. My guess is it chips and dulls the edge of the edge less resulting in a crisper edge.

Why is the range of the base stone wider on hybrids with edge leading on the finisher as opposed to edge trailing or stropping on the finisher?

With edge trailing, you are more polishing the scratch pattern of the base stone than altering it in any significant way.
With edge leading, the chipping action will alter the shoulders of the edge of the edge. I am guessing this process mellows out the otherwise way too toothy edge you would normally get of something like a 600.

So, what are the benefits of this technique?

Apart from an edge which is super keen with solid bite, its a pretty easy edge to produce.

I find with edge trailing, burrs and wires take a lot of skill to deal with effectively and if you don't, the edge looses its initial sharpness quickly. Edge leading on the finisher pretty effectively puts an end to that problem making the edges more reliable and durable.

Its very fast. Taking a base 1K edge with 65 Rockwell AS steel to completion with the 16K literally takes 4 to 7 strokes per side and no time spent dealing with deburring.

It gets rid of all the stones one might normal have in the progression between the base and the 16k.
I could easily see a setup with something like a Shapton pro 220 followed by a good 600 like the Carter Pride if you can get it, or the Geshin, followed by the Shapton Glass 16k.

220 covers damage and bevel setting.
600 refines that and deals with crap steel.
16K used a little for the Germans and a varying number of additional strokes to cover various stainless all the way up to great carbon.

And the down side?

The Shapton Glass 16K is not a cheap stone and while it doesn't feel bad, its not the best feeling stone in the world.
The technique wont work of 3K base stones which to me are some of the most pleasurable stones to use.
The technique precludes a lot of stones many of us already have and like using.

So yea, I'm a grass is greener type so will probably be of on some other edge adventure as soon as the wind changes but this technique is definitely one I'm really enthusiastic about and will likely use a lot.

 

[kayman67]

This looks a lot like something I've been doing, but I usually use a very fine hard Jnat. Hits a nice balance between anything, having a very aggressive edge in the end.

 

[branwell]

This looks a lot like something I've been doing, but I usually use a very fine hard Jnat. Hits a nice balance between anything, having a very aggressive edge in the end.

Am with you on the Nats, and to that end, where stones like the Belgian Blue I didn't care much for on Kitchen knives because the edge it left was too smooth and lacking bite, used in this way, it works great. Opens the door to try a bunch of other Nats I otherwise wouldn't have tried.