Thickness vs width

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WeekSecret

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Apr 28, 2021
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I'm starting to get more knowledge in knife and I'm starting to wonder why there is always the thickness written in the spec and rarely the width.

I'm asking because I know the height of steel is much stonger than the thickness. A flat stock of 1" width and 0,2" thick is as strong as a flat stock of 1,3" width and 0,1" thick on a vertical stress, the later being much lighter.

Now I realise flat stock ain't the same as a triangularish shape, but I don't see why thickness matter more.
 
Thickness has a lot to do with how the knife will perform various tasks.

A thicker blade typically will have a more obtuse (broader) final edge grind and is better suited to chopping and heavier-duty use, where fine slice cuts are not required. It is better suited to heavier tasks as the edge has just that much more steel behind it to support it.

A thinner blade lends itself to having a more acute (pointier) secondary edge grind, and is a better choice when finer "slicier" cuts are required.

It's all about edge geometry and what lends itself best to what you intend to do with the knife.
 
shane45-1911 said:
Thickness has a lot to do with how the knife will perform various tasks.

A thicker blade typically will have a more obtuse (broader) final edge grind and is better suited to chopping and heavier-duty use, where fine slice cuts are not required. It is better suited to heavier tasks as the edge has just that much more steel behind it to support it.

A thinner blade lends itself to having a more acute (pointier) secondary edge grind, and is a better choice when finer "slicier" cuts are required.

It's all about edge geometry and what lends itself best to what you intend to do with the knife.
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I think that misses his point. You can't conclude anything about the geometry at or near the edge without talking about the height, which is why height matters at least as much.

Let's see if I remember by grade school geometry (maybe!). Suppose we have two rectangle shaped blades for the sake of simplicity rather than like a drop point or something else so that the distance from edge to spine is uniform across the blade. Knife 1 is full flat ground 1/8" at the spine and 1" tall. Knife 2 also is full flat ground but is 1/4" at the spine and 2" tall. Would you call the first one "slicer" and second thicker and better for harder tasks because of edge geometry, concluding based on spine thickness alone? In fact they're the exact same thickness from the edge to up an inch high up (where knife 1 ends). One is not thicker at the edge than the other.



To the OP's question, I imagine it is because blades aren't rectangular so that providing a height measurement takes a decision on how to measure. There are some makers and companies who do provide blade height, however.
 
Thicker knives can split wood where thinner knives tend to bind badly. It is not a given, but will hold true for a reasonably well designed knife. Of course just having a thicker and wider flat sided slab with minimum edge, like some of the British Dmod knives will still leave you with a hefty junker that can neither cut nor split.

n2s
 
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kreole said:
I think that misses his point. You can't conclude anything about the geometry at or near the edge without talking about the height, which is why height matters at least as much.
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Most knives have pictures. It isn't that hard to guesstimate the approx. height of a blade, if the spec is not given.

Thickness is not so easy to see in most pictures, and matters much more (to me).

And yes, there are a lot of variables when it comes to primary grind angles and thickness. But again, you can usually tell the general angle or type (full flat, sabre, etc.) of the primary grind by looking at pictures.
 
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Not too thick , but very wide blade for a folder (Cold Steel brand ) :cool::thumbsup::thumbsup:

 
The Colosuss was very interesting; it is much shaper and lighter than you would think.

n2s
 
WeekSecret said:
I'm starting to get more knowledge in knife and I'm starting to wonder why there is always the thickness written in the spec and rarely the width.

I'm asking because I know the height of steel is much stonger than the thickness. A flat stock of 1" width and 0,2" thick is as strong as a flat stock of 1,3" width and 0,1" thick on a vertical stress, the later being much lighter.

Now I realise flat stock ain't the same as a triangularish shape, but I don't see why thickness matter more.
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You can see the width of the blade and make a fairly accurate estimate. Small errors in the estimate do not make a large difference in performance of the blade.
But the thickness is more difficult to estimate, and a small error in your guess can make a big difference.
So most sites will tell you the blade thickness, but just show you the blade width.
 
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Somehow I quoted a post I did not mean too and it wasn’t posted automatically?
 
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I think knarfeng knarfeng is spot on.

I’ll add that the width is a variable. Depending on how heavy handed the guy doing the grinding is and what edge defects he is grinding off.

I’d bet some production knives vary 1/8” in width just because of who ground it on what day and if they were awake.
 
eveled said:
I’d bet some production knives vary 1/8” in width just because of who ground it on what day and if they were awake.
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i like thin blades, as they will slice...if also thin enuf behind the edge.
i've never miked a blade's width that deviated more than ten mils from stated width.
perhaps some gas-station knife...i suppose.
 
Okay I will clarify my question a bit;

I ask because I would like to know what to expect from different blade.

By exemple if I intend to do a little bit of batoning, would a condor el savador do the trick or should I go with the condor duku which is twice the thickness, but with a lot less width.

If I intend to do "heavy" chopping with a knife, would 3/16 be more than enough, do I need to go 1/4 or a large 1/8 knife be ok? What if I want to baton with it?

Why most 10-12" inch knife are 0,25" thick while 18" machete are 0,1"? I get the're not use for the same job, but if you hit a rock, it's way harder than heavy chopping.

Overall, should I look for a light large and thin knife or a medium weight, medium width and more or less thick knife?
 
Bothe height and thickness are important to performance. I think it's called aspect ratio. Different thickness at the spine and height will result in a different angle or aspect ratio near the edge or behind the edge.
 
singularity35 said:
Bothe height and thickness are important to performance. I think it's called aspect ratio. Different thickness at the spine and height will result in a different angle or aspect ratio near the edge or behind the edge.
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What about two blade with a saber grind with the same edge angle? "Same" sharpness, but would the edge retention be affected?

I don't see how a thicker blade would be stronger on anything but prying and batonning
 
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WeekSecret said:
What about two blade with a saber grind with the same edge angle? "Same" sharpness, but would the edge retention be affected?

I don't see how a thicker blade would be stronger on anything but prying and batonning
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I don't understand your question, sorry.
 
WeekSecret said:
What about two blade with the same edge angle, making them with the "same" sharpness, one thicker and the other wider. Would they have the same edge retention?
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The problem with trying to make a broad assumption about "sharpness" and "edge retention", is that it involves so much more than just thickness and width.

Proper and consistent heat treating and tempering is a HUGE factor when discussing edge retention, much more so than physical blade dimensions and angles.

Type of steel is also a major factor in determining edge retention.

Then we get into grind types. A convex grind is typically "stronger" as it puts more meat behind the edge - but the trade-off is that convex won't finely slice as well as a hollow grind or a thin full flat grind. So "sharpness" becomes very hard to standardize. It depends on what you want your knife to cut. An axe can be sharp, but won't thinly slice tomatoes worth a damn. So to the tomato lover, he may say the axe is "dull" even though the edge may be perfectly executed with regards to grind angle and evenness. Just as you wouldn't try to use a surgeon's scalpel to try to cut down a tree. The scalpel is razor-sharp and can shave hair with ease, but it won't cut down a tree. See where I'm going with this? Both the axe and scalpel are sharp, but only as defined by the intended application you are using them for.

I honestly think we (you) are trying too hard to reach a tangible, definable conclusion to this. There are way too many variables that go into the "sharpness and edge retention" equation (including those I mentioned above) to try to generalize a conclusion that goes well beyond thickness and blade height/width.
 
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I agree of course that height matters just as much as thickness for overall robustness. However, a "higher" knife limits your tasks. Which is why - for example - de-boning/fillet knives are very low.
 
WeekSecret said:
What about two blade with the same edge angle, making them with the "same" sharpness, one thicker and the other wider. Would they have the same edge retention?
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The angle of the primary bevel (the angle between the cutting bevel and wherever the grind starts) can drastically change how the knife performs in use, even if the edge bevels are the same angle. If you have two knives with the same blade stock, one that's saber ground and one flat ground at the same primary bevel angle and edge angle, the flat-ground blade will be thinner behind the edge (possibly by a significant margin depending on where the saber grind starts). Generally speaking, the flat ground knife will slice easier because there's less drag through the material, while the saber ground blade would likely be "tougher" or more stable because it's got a less delicate geometry.
 
shane45-1911 said:
The problem with trying to make a broad assumption about "sharpness" and "edge retention", is that it involves so much more than just thickness and width.
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I'm pretty aware of that, it's simply that I got the "buy once cry once" ideologie, so I'm looking for a 300-400$, s30v stainless or more, fighting/survival knife.

I'm asking mainly to give pro and cons to the knives I find.
 
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