My neighbor's cleaver just kicked my ass

[Drayquan]

(Sharpening with whetstones for about 3 years now, I've improved a great deal but know I still have a LOT more to learn. I sharpen for myself/family/friends, and in the past year, for neighbors for extra cash now and then. In general, results have been good and everyone's happy.)

So a neighbor just asked me to sharpen their set of Henckels kitchen knives. Most of them needed some thinning/re-profiling, my (newly arrived) chosera 400 was able to take care of that easily before a standard progression to 1k, 4k and 6k finish.
No problem, they turned out beautifully.

Then comes along their cleaver. Holy hell, FML.
It was fairly dull and beaten up but looked totally serviceable; I haven't done many cleavers/choppers in the past, but got decent results on the few I've done.

Each side approx a 30° angle (good, keeping that), generally flat but varied with some unevenness/micro valleys here and there. Some tiny micro-chipping along a few inches of the apex, some rough grind marks along the top ridge of the primary bevel from a previous sharpening. These grind marks are deep enough that when removed it would modify the flat grind into a bit more of a convex grind, I assume it'll be a little more work but should turn out nicely.

About 15 minutes in starting on the chosera 400 (applying minimal force when edge leading, a little more force edge trailing), I was noticing almost no change whatsoever on the edge, except for a minor visual surface texture change. 30 minutes total pass, still no real change, so I increase my pressure a bit. 45 minutes total, no burr yet but I've swapped sides a few times since starting to try and keep things even. Sweat starting to drip, 1 hour total, the previous sharpener's grind marks are still there, and the freaking tiny micro edge chipping still hasn't smoothed off. What the hell!?

@ 1hr 30min I finally got an extremely tiny burr, I've smoothed/evened out 90% of the edge surface and established a mostly even arc to the top of the primary bevel, removing some of the old grind marks, but not all. It's not as clean as I'd like, but at this point my chosera 400 is down a few millimeters too many, coughing up so much blood..I mean mud, I figure I've destroyed enough of the stone for today. I have an old worn down cheap budget corundum stone laying around (800grit), I give it some passes and you know what? It seems like its working better than the chosera 400 (maybe its just in my head).

@ 2.5 hours, I say enough grinding. I give it some passes on my primary 1k stone, then some stropping on the 6k which does add a nice aesthetic surface polish. I'm not happy with the edge and overall the cleaver isn't to my service standards, but I call it quits. 3 hours total on one 6" g'damn cleaver, holy hell.
This thing kicked my freaking ass.

I don't know for sure, but I assume a few things:
- My skill with cleavers needs a lot of improvement
- The heat-treat / rockwell hardness was way too high for my specific coarse chosera stone
- Maybe I needed a good coarse diamond plate for this
- A hardcore belt grinder would have far better to start this on

I regret subjecting my chosera 400 to that abuse... sigh
This was cathartic for me, thx kitchen knife forums

 

[zitangy]

really rounded cleavers.. 100 grit wld be a good start.. Usually i start with 200 grit

Chosera 400 is not an aggresive stone at that grit..

Its not a question of technique i wld say... just not a proper choice of grit for the job on hand... rgds Z

 

[inzite]

sounds like you were trying to thin instead of just sharpening which is why it took so long to remove enough metal to raise a tiny burr (meaning you finally reached the edge). chosera 400 isn't aggresive at all and i would say finer than 400 grit, you probably need a lower grit stone to do the major metal removal.

 

[Benuser]

If that cleaver was a Henckels as well, please be aware those European ones hardly have an edge and are very rounded to avoid splintering when going through bones. And soft stainless is very abrasion resistant. For thinning, think a coarse Shapton.
IMHO it doesn't make much sense to look for a polished edge with soft stainless. I only sharpen them with said Chosera 400, and very lightly strop and deburr at 800. Split leather in between perhaps, or cardboard.

 

[daveb]

Was the cleaver a Henks? That's a lot of metal to rework.

I would not have spent time thinning, just get some edge to it with a 220ish stone. And that would prob take awhile. If they come around again next year suggest you move.

 

[chinacats]

Others pretty much said it all but I'd add that it's likely not a very high hrc but more likely just as stated lower quality, abrasion resistant stainless steel.

 

[Dave Martell]

Sounds like my reoccurring nightmare.

 

[Drayquan]

If they come around again next year suggest you move.

Made me smile and chuckle

Sounds like my reoccurring nightmare.

Glad I'm not the only one!

it's likely not a very high hrc but more likely just as stated lower quality, abrasion resistant stainless steel.

The cleaver's steel was tougher than Rocky in part 4. As far as HRC/type of stainless steel, you're probably right.

Anyway,THIS ISN'T IT, HOWEVER, the one I slaved over looks similar after I finished it. Similar blade shape, but it didn't have nice full tang handle like this one - it had a cheaper molded handle (maybe polypropylene) with a hidden partial tang.

For thinning, think a coarse Shapton.

After this, I'm seriously considering the Shapton kuromaku(pro) 120, it's decently priced in the US (I live in Canada, but including conversion, I'll be paying about $16 more if I buy it here rather than ship it from USA), but I have 1 hesitation: It's relatively thin (only 15mm), and when you consider what very coarse stones in that range will be used for, would you really want a thin stone for those jobs? ..or is it super durable/long lasting for its size? I've been doing a lot of neighbor's knives this spring/summer (will probably continue through to the fall) and the chosera 400 is actually wearing a bit faster than I thought it would, even before it was subjected it to the dreaded cleaver.

IMHO it doesn't make much sense to look for a polished edge with soft stainless. I only sharpen them with said Chosera 400, and very lightly strop and deburr at 800.

Yea, I would have also stopped around 800-1000 for final light strop/deburr if it was for my own use - I just put it on the 6k for a few minutes to make it look a little prettier for them (which of course is entirely subjective, but imo it did make an aesthetic improvement to have the nice 6k polish along the mostly smoothed out semi-convexed edge which I was able to finally achieve. The polished finish won't last long but it makes for a nice presentation when handing it back to them, know what I mean?

 

[Barclid]

****, Norton crystolon and call it a day from me. Something I can really bear into and eat some metal. I like to spend as little time as possible on ****** stainless. Spend some time cleaning the apex and you're good.

 

[Benuser]

The polished finish won't last long but it makes for a nice presentation when handing it back to them, know what I mean?

Not just the polish won't stay, it weakens the edge.

 

[Drayquan]

Not just the polish won't stay, it weakens the edge.

Ah. See, this is one of the best things about this forum - I never would have considered that a simple polish along it's fairly large bevel would actually weaken the edge in this case. Thanks Benuser! I appreciate the tip
Its nothing a micro bevel can't fix though, right?
What about if next time, I still give it a nice quick polish purely for first looks/presentation upon return to it owners, but I apply a micro-bevel at say 35° - 40° (each side, on top of a standard cleaver grind of 30° per side) to strengthen it up? Now that I think about it, that should probably be done regardless (for a chopping cleaver), maybe even wider, depending. Yes/no?
I'm being stubborn and should totally forget the stupid polish all together, right? lol

****, Norton crystolon and call it a day from me. Something I can really bear into and eat some metal. I like to spend as little time as possible on ****** stainless. Spend some time cleaning the apex and you're good.

Going to look into these, looks like you get a discount for 3, nice.


Thx again for the help people!

 

[Benuser]

I don't hope your lovely neighbours use that German cleaver for anything else than going through bones, that's what it is meant for. It's no Chinese or Japanese cleaver you use for chopping and even slicing almost everything. In fact, there is very little use for a Western cleaver in a home setting.
As for the other knives, once thinned with a really coarse stone you may use the Chosera 400 both for sharpening as for removing the scratches the coarse stone will leave. It's quite good at it, and leaves a rather pleasant finish.

 

[Benuser]

I would never thin a Western cleaver. You want both convex sides to end in a very obtuse kind of edge. Perhaps there is a bit of damage to be repaired, but certainly no geometry change to be even considered.

 

[Benuser]

To give an idea what kind of result you may expect using the only 400 to remove the shoulder, convex the bevel and provide a working edge on a new Wüsthof Le Cordon Bleu. No further thinning. For my personal use I find the look acceptable. If not, you probably will have to rework the finish on the entire blade.

 

[LifeByA1000Cuts]

In my experience, the Chosera 400 needs to be very frequently cleaned (eg with a cheap carborundum stone) when abrading large amounts of modern stainless.... clogs faster than it renews itself.

 

[Benuser]

In my experience, the Chosera 400 needs to be very frequently cleaned (eg with a cheap carborundum stone) when abrading large amounts of modern stainless.... clogs faster than it renews itself.

Which modern stainless you have in mind? Only seen some clogging on the 800 when thinning the soft stainless cladding of a San-mai. Easily solved by using more water and less pressure, or using a much coarser stone or an Atoma.

 

[StonedEdge]

Shoulda started with a rough file or a 140 grit diamond plate! Choseras work too slowly for this kind of work.

 

[Keith Sinclair]

You are doing well to sharpen those German gyuto's. The cleavers are thicker as said the stainless is abrasion resistant, which makes it even harder to sharpen. For cheap stainless bone cleavers use a 80 grit belt and a bucket of water.. Would not waste any stone on those things. Belt for the burr & a med. stone to finish. On many stainless bone cleavers the the grind is crap and so is the steel.

Carbon bone cleavers are also softer hrt. but much easier to sharpen. Also Chinese know how to put a grind on a bone cleaver.

 

[LifeByA1000Cuts]

@Benuser well, VG10 certainly is a major offender (The perceived speed difference between "freshly flattened" and "used it for a few minutes, while doing some thinning work on a Tojiro ZEN, was about 5:1 to 10:1) ... I did assume a similar effect would happen with "western" stainless too (think I have seen it, though less pronounced... not sure how strong, since I did make a habit of flattening frequently with that stone...).

 

[Benuser]

Didn't notice clogging with plain VG-10. I guess some soft stainless cladding was the culprit.

 

[LifeByA1000Cuts]

Maybe ... but then, they'd make a cleaver in Germany from what they'd make the cladding for a ZEN from in Japan....

 

[aaamax]

Not just the polish won't stay, it weakens the edge.

If one was going for say a 10% angle I could see that, but with a more stout apex, why would a higher polish weaken it?

 

[Benuser]

The 4116 have large carbides in a soft matrix. High polish will weaken further the matrix without abrading the carbides who will tend to break out. Expect a very poor edge stability, even when sharpening at an obtuse angle.

 

[aaamax]

The 4116 have large carbides in a soft matrix. High polish will weaken further the matrix without abrading the carbides who will tend to break out. Expect a very poor edge stability, even when sharpening at an obtuse angle.

Interesting, I didn't know that.
from a blade making standpoint, wouldn't one be able to refine the grain structure by a few normalization cycles? or is it that nothing can really help these cheap stainless steels?

 

[Benuser]

No metallurgist here. Some 4116 are finer than others, but that's just the impression I get when sharpening. Anyway, the soft matrix remains.
It's a deliberate choice by the German makers to make tough blades who can stand a lot of abuse.

 

[Smashmasta]

When I run across these kinds of things, i actually use a semi coarse file, with the cleaver in a vise to do the really heavy lifting to set up the bevel shape, and then start with my stones to start flipping burrs. Just wrap the cleaver in some towels or whatever, and find an angle that allows for a little bit of elbow grease, and you can generally make quick work of the first step. I've found a small vise to be a very helpful tool for things like this, to serrated knives, to finner touch ups with smaller more delicate watch files. I'm putting together a belt grinder which is certainly ideal, but if that's out of the question, this is a good place to start for abrasive resistant cleavers that have never seen a stone in its life.

 

[LifeByA1000Cuts]

@Benuser as a German, I still *want* to believe correctly done 420J2 getting sharper and holding light-use sharp edges better than some 4116 is an illusion on my part But the empirical evidence is mounting...

But then, there is at least one known maker that made straight razors out of 4116.....

 

[Benuser]

Dovo does indeed IIRC. But a razor hasn't to suffer as a kitchen knife edge. No board contact, no hard or fibrous stuff. The edge instability of a polished 4116 only becomes evident during the actual use in the kitchen.
No experience here with 420J2.
In fact, I'm hardly interested in stainless. The lack of sharpening fun keeps me away from most of them. I've tried a few out of curiosity. And carbons look much better.

 

[aaamax]

I wonder if possibly older, as in 25years+, Henckles/Wustof blades were different than today's offerings. Because I often sharpen the older versions and can take them up to 4k and the edge can last surprisingly long time.

 

[nopomo]

I wonder if possibly older, as in 25years+, Henckles/Wustof blades were different than today's offerings. Because I often sharpen the older versions and can take them up to 4k and the edge can last surprisingly long time.

The newer Wusthofs are thinner and a couple of points harder, so if anything they should be better in this regard. Maybe the discrepancy is that some people think that if they themselves can't do something then it can't be done.