# Hollow grinding on blades = shorter life?



## coup-de-feu (Aug 4, 2010)

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coup-de-feu


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Dec 21, 2012








So here are some hollow ground knives. They are great to work with, but see how there is only an eighth of an inch or so until the cutting edge creeps up into the hollow grinding after X amount of sharpening? Doesn't that make the cutting edge wavy? If the edge is wavy then how do you sharpen it good? My question is does hollow grinding reduce knife life by limiting the amount of blade that can be sharpened.

I like them, I just cant see throwing down that kind of money on a blade that will be bent up and wavy after 2 years no matter what.

CDF


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## franzb69 (Jul 9, 2012)

i've seen people still use their knives even when the grantons were already halfway done and they were fine. but it does mess with your image of a knife. it will still help with stiction but will just look funky.


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## knifesavers (Oct 5, 2011)

The original Granton knives are down to the edge and made in England.

http://www.granton-knives.co.uk/granton_edge_knives.html

Your knive have large kullens but are not a real hollow grind. Hollow grinds have a trench the whole blade length behind the edge.

Jim


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## franzb69 (Jul 9, 2012)

didn't know that. thanks knifesavers.


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## phatch (Mar 29, 2002)

To just say hollow grind = shorter life is not enough information about the knife to judge this anyway.

In manufacturing, hollow grinding is often easier and cheaper to do than a flat grind. I know of one example where Darrell Ralph was having one of his custom knives turned into a production knife at Camillus. Camillus really wanted to hollow grind it to keep costs down, but the customers wanted a flat grind. The compromise was to hollow grind it on a 14" wheel such that the blade looked flat ground to the naked eye and behaved much like a flat ground blade in use. you could detect it with a straight edge laid along the chord of the blade.  An even bigger wheel would be needed to pull this off for a kitchen knife, but there's a lot that can be done with a grind than the type alone describes.


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## petemccracken (Sep 18, 2008)

A _caution_, it appears that the discussion may become confusing over semantics.

From my viewpoint, the OP is talking about the _gratons (sp?)_ and not the knife edge and is using the term _hollow grind _in an unusual manner.

For me, a _hollow ground knife_ has a concave edge, )(, as a result of using a wheel to grind instead of a flat.

Gratons are hollows in the blade.


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## foodpump (Oct 10, 2005)

What Pete said.

A hollow grind is along the edge of the blade--parallel to the edge.

This is/was a common method of sharpening for wood workers for tools like chisels and plane irons.  The "hollow" allows for quicker honing and sharpening as less materials has to be removed. This is the only reason why.   I do not endorse this method for knives, and the only knives I see this on are the lousy ones.

Grantons or "Kullenschliff" was developed for moist, sticky foods like cheese, smoked salmon, and for cutting thin slices of beef or ham.  As you draw the blade through the food, you are pulling pockets of air inbetween the slices, which helps the slices not sticking to each other or the knife. 

I can not understand why a granton edge is being offered on a Chef's knife--maybe because "they" still haven't figured out a way to put a USB port or a laser guiding system on the knife???


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## coup-de-feu (Aug 4, 2010)

Yes Pete, I meant Gratons, the divots along the side of the blade.  Thanks for correcting me.

I checked out your link to the original granton knives, Savers, and I see that the dimple goes all the way to the sharpened edge.  So, having some varied thickness, different sharpened angles, and a wavy edge is not a big deal?  Yep, messes with my image of a knife.  But if it works it works...

CDF


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## duckfat (Aug 7, 2008)

> Originally Posted by *Coup-de-Feu*


If it did then there would be a LOT of meat slicers with dead blades, probably not the best example considering how many dull slicers I've seen but I'd venture a guess that many of us have sharpened a slicer blade a time or two.

Dave


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## boar_d_laze (Feb 13, 2008)

You can still get a decent edge on a Glestain once you've sharpened into the dimples (aka "grantons," aka kullenschliffen, aka kullens, aka "hollow grind," etc.) because they're only on side, and you can get an even bevel on the other.

It's doable as long as you can handle a lot of asymmetry. In fact, real Granton knives come from the factory with the edge cutting into the kullenschliffen.

Just like sharpening a wavy edge, do what you can with a "file" or slip" on the side with the dimples and sharpen a chisel on the other side of the knife. Some sharpening machines do a pretty good on those sort of edges, and -- while I can get a passable edge -- I'm not a big fan of hand sharpening them if machine sharpening is available.

I don't like Glestains anyway. They're heavy, awkward, and -- like Shun and Global -- an overrated knife whose time has passed. They're made from a passe alloy, but are expensive. Their chief value was that they were a helluva lot better than the classic Wusthofs and Henckels which ruled western kitchens in the eighties. But so what? So are scores of other knives.

BDL

_PS. Note: "Granton" edges were designed and first manufactured by the Granton Knife Company, and that Granton is a registered trade mark. Note also, that very few copies work as well (Glestain is one of the few exceptions which do), and that Grantons are very good bang for the buck._


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## lazy sharpener (Dec 17, 2012)

Hey, BDL -

Your views on what's a passe alloy, what's an au courant alloy, and what difference these alloys make in practice (edge durability, brittleness, etc.)? Or are we just talking fashion?


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## lazy sharpener (Dec 17, 2012)

Based on the picture that came with the start of this thread, it seems that several years will pass before reasonable sharpening starts to intrude on the Glestain scallops. (As BDL says, keep it honed, and you won't be sharpening much.)

Far as I can tell, the dimples/kullens on Glestains are much more radical than the food-releasing scallops/dimples/kullens on santokus and on so-called Granton-edge slicing knives; the Glestain dimples don't alternate on each side of the blade, as the others do, thus mooting the food-releasing argument; and some Glestain models have double rows of dimples (divots, rather?), one facing down toward the edge, one facing up toward the spine - to what end? Beautiful they may be - just like the Hotel Okura - but form-follows-function? Perhaps more like Star Wars.


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## boar_d_laze (Feb 13, 2008)

Lazy Sharpener said:


> Hey, BDL -
> 
> Your views on what's a passe alloy, what's an au courant alloy, and what difference these alloys make in practice (edge durability, brittleness, etc.)? Or are we just talking fashion?


Glestains are "Acuto 440," which is at the high end of the 440C family with more moly than "ordinary" 440C. Acuto 440 is good compared to ordinary 440C, but not very good compared to what other makers are using for knives of the same price. In one respect at least, edge taking, it's better than ordinary 440C, but otherwise suffers from the same, edge-holding limitations. That is, it's simultaneously soft -- about as hard as Wusthof's X50CrMoV15 -- but wears quickly.

440C was formerly a "wonder alloy," but has gone out of fashion -- at least among the kitchen knife cognoscenti -- because it's not very good steel compared to the other stuff that's currently on the market. I guess manufacturers feel the same way because while you don't see successful 440C or Acuto 440 knife lines pulled from the market, you don't see new ones coming in either.

It's not easy to tell whether new steels are popular with knife makers because they're new or because they're actually better. It's almost inevitable that newer alloys will be perceived as better simply because they're newer; and even knowledgeable users get caught up in the hype. It takes some time for the real world to work its magic. VG-10 was considered an ultimate alloy not long ago, but now that we've had a better chance to see its limitations the general opinion has moved its status down to merely "good." In the meantime, the reputation of other alloys, like G3, has actually improved.

Something else to think about, is that it's never just about the alloy. How it's handled -- especially how well it's hardened -- by a given maker has to be considered as well.

BDL


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