# hallow edge knife ?



## thumper1279 (Jan 24, 2013)

hi i was wondering i have never really seen anyone in the kitchen use a hallow edge knife before but i have heard some stuff some people always say im going to get one one day but they never do 

is it correct in my mind of thinking that a hallow edge is not good for everyday use like i mean someone once told me its a veggie knife 

and not good for meats 

but i don't know much about it so i am here for help on this subject can someone point out anythings that a hallow edge knife would not be good to use on that a standard chef knife blade can or vis versa please 

Thank you


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## michaelga (Jan 30, 2012)

If used everyday you will quickly end up sharpening down to the 'hollowed' edge part and then have a scalloped edge bread knife.

Not really the way to go for line use.  Some still do though.


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## galley swiller (May 29, 2013)

If it's a "hallow" edge, then I suppose that means the edge has been blessed in a religious ceremony. Not that we don't treat our knives and their edges to sanctification on this forum from time to time..../img/vbsmilies/smilies/rollsmile.gif

I am presuming you are really referring to "hollow-ground" edges. That means the edge is formed by having concave primary bevels on both sides of the blade. That results in a very thin support leading to the actual edge. It does provide a very sharp edge. It also means that as the edge is worn down, the blade will remain thinner longer and sharpness will last a bit longer.

However, there are problems.

First, the thinness behind the immediate edge often results in a faster collapse of the edge, so a knife will need more honing, more often. With more edge collapses and honings, the wear on the edge is significantly accelerated.

Second, the removal of blade steel is accelerated if the knife is hollow-ground. This can more quickly bring the knife to the point where the thickness of the blade creates wedging problems. At that point, the entire blade has to have both faces "thinned" - a major task - or the knife must be replaced.

Third, hollow-grinding can only be done with wheels. If the wheel is not water-cooled, then the steel in the blade at the immediate edge area can be heated to the point where the tempering of the steel is adversely affected. The usual solution for that is to use a water-cooled wheel. However, those are few and far between, as the saying goes.

You are at the complete and total mercy and skill level of the sharpener, if you send your knife out.

Those are among the reasons that sharpening your knives yourself by stone or jig is so highly recommended. A knife sharpened on a stone will be either flat or convex ground. A knife sharpened on a jig (such as the Edge Pro) will be flat ground.

If you want to learn about concave edges (the reverse to hollow-ground knife edges), watch these videos from Murray Carter:

About convex sharpening: 




How to convex sharpen: 




Hope that helps

Galley Swiller


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## michaelga (Jan 30, 2012)

So which on were you talking about?


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## galley swiller (May 29, 2013)

The ground indentations on the face of the blade on the pictured santoku are properly known as "kullens" or "kullenschliff", ("Granton edge", "scallops" and "dimples" are also names used, though kullens or kullenschliff are the proper names).

"Hollow ground" refers to a type of edge grind, with a partially concave edge along the entire length of the edge. Hollow ground edges are often found on straight razors, but not all that commonly with better chef's knives'

Yes, if you sharpen the edge of a knife with kullens to the point where the edge of the knife reaches the kullens, further sharpening will result in an inadvertently serrated edge.


Galley Swiller


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## foodpump (Oct 10, 2005)

Ditto what Galley Swiller said.

Hollow edges are commonly used on woodworking tools like chisels and plane irons.  These tools have a single bevel of about 25 degrees and the "hollow" makes honing or re-grinding faster because less metal has to be removed, and the bevel can be laid directly onto the stone. The same principle is used for straight razors, as the blade can be laid onto the strop and maintains the bevel. 

I only see the hollow grinds on cheap knives.

Why?

OK, let's say your knife blade is 1/8" thick at the spine.  It HAS to taper down to nothing at the edge, right?  A "good" knife will be tapered gradually along the blade, either through forging or grinding. This (grinding or forging) is fairly labour intensive and is one of the factors that makes a good knife expensive

On a cheap knife (the kind that aren't sold in stores, but through a network of college kids acting as sales reps.  I don't want to say the name, because then we will get more sales B.S. from reps on this site)  Where was I?  Oh yeah, on a cheap knife, the blade is 1/8" all the way to about 3/4 from the edge.  Now it HAS to taper down to nothing.  Easiest and cheapest way to do this is to put in a hollow grind. No expensive grinding along the whole blade, and certainly no forging.  With such a knife, you will find it behaves more like an axe than a knife.  Because the item you are cutting has to spread 1/8" apart in such a short distance (3/4"), it tends to split rather than cut, regardless of how sharp the edge is.


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## rick alan (Nov 15, 2012)

The standard for home use stainless kitchen knives for many years was a blade between a mere 1-1.5mm thickness with the edge ground hollow for about 6-12mm.  As you can imagine the thickness behind the edge can be pretty thin, and stays that way after many, many sharpenings.

For vintage knives you can look on ebay for Deluxe Persona (high end) and Imperial Very Very Sharp (still in business here in RI,  but only making cheap novelty pocket knives now).

I have examples of both and still enjoy using them occasionally.  One is my cheese knife now, another used just for slicing mango and occasionally lemons, still another for soft bread.  They are really not for the pro environment or the serious home-kitchen user, though you can still find some new NSF chef knives that run about 2mm thick and have a hollow ground edge.

Rick


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