ideal blade thickness

[hardheart]

wish the search function was working when trying to search more than one word, but anyway...

If you have access to an axe, chainsaw, crowbar, screwdriver, hammer, whatever, how thick do you want the bladestock on your knife? I think 1/8 is plenty, and there isn't anything wrong with thinner-kitchen knives, machetes, harvesting blades and such.


And then, when you can't go to your toolshed, what do you want then? I believe some of the HI kuks get up to 1/2" thickness.

 

[spyken]

depends on the usage. but I like them as thin as possible - 0.125 seems to be fine. Thinner would be better.

 

[Jason Cutter]

Of course a lot also depends on all the other variables in the knife - width, length, bevel shape, edge thickness, steel type, heat treatment and the intended use.

All things being equal, I like 1/8inch thick blades with a thin flat grind to do most cutting, slicing, fine cutting chores. Some would argue that you don't need a thicker blade steel. If you're going to chop, get an axe... BUT, a big knife that might be considered a "fighter" or do-it-all, like a Bowie, could benefit from a 3/16inch thickness for extra heft. I find that its rare to need a 1/4inch thick blade. I personally feel that if one is relying on the sheer thickness of the steel to provide strength to the blade, one might be either using the wrong steel, or one might be using the knife wrongly...

In the end it depends on how the maker / manufacturer manipulates the various parameters. I believe in specialised knives for specialised jobs, so I use blade thicknesses ranging from 1/16th inch all the way up to 7/32inch thickness. I have only ever made 1 knife from 1/4inch thick stock. Most are 1/8inch or 5/32inch. Jason.

 

[Planterz]

Jason is right, there's much more than just thickness. A .150" thick blade can cut certain things "better" than a .125" blade if it's ground the right way (like hollow vs flat). What it comes down to is the proper blade for the job.

 

[Cliff Stamp]

If you have access to an axe, chainsaw, crowbar, screwdriver, hammer, whatever, how thick do you want the bladestock on your knife?

when you can't go to your toolshed, what do you want then? I believe some of the HI kuks get up to 1/2" thickness.

I used to think just go as thin as possible to maintain stiffness, then I used a number of thin flat ground knives which wedged badly because they were too thin, in particular for Chef's knives, flat ground, 1/16" takes more force to cut with than 1/8" on most vegetables as it doesn't split them and thus you get a lot of side friction. You can get around this however by using decent hollow relief grinds. It is difficult to go under 1/16" though as the blade starts becoming floppy unless it is very short and very hard.

On thickness, if the blade is fully hardened, or spring spined, for raw strength 1/4" stock is *very* durable, 3/8" just insanely strong. You can still want greater thickness though if working on soft wood cutting to prevent excessive binding, it also gives more power on the cut, and with the HI khukuris, compensates for the less than spring hardness spine. They are a very cohesive design all elements work towards a common goal.

-Cliff

 

[hardheart]

Well, discussions in several other threads recently led me to start this one. Steel, grind, and heat treat all have a tremendous amount to do with a blade's cutting ability, but I wonder where people feel there is the least compromise of any component. A blade with a thick spine but a hollow grind-don't those 2 characteristics cancel each other out to some degree? The blade loses strength in the reliefs, but the thickness can affect cutting and sharpening (depending on design, of course)

Also, I was thinking about the Americanized tanto yesterday, after seeing some photos of a torture test. One of the first things I did when I got a tanto some years ago was to compare the spine to that of a saber ground drop point. I had read so much about how the tanto kept it's full spine thickness almost all the way to the tip. So does a saber ground drop point And I began wondering just how profile and stock thickness is. The drop point is ubiquitous, so I don't think it ever got the hype of the tanto.

Cliff Stamp, if I am understanding correctly, you are saying that a flat ground 1/8" blade should perform as well as a hollow ground blade of thinner stock. That is quite interesting, and also pretty much the kind of example I was looking for.

I haven't owned a khukuri (hope I spelled it right that time) before, is it anything outside of a chopper? It seems that it and a quality, sharp axe are almost interchangeable. Some of the camp/survival threads draw a clear line in preferences. Some people say they need little more than an SAK with small, thin flat ground blades, perhaps complemented by an axe or other 'chopper', while others want a larger, heavier knife that they believe combines everything they need into one package. They HIs do come with a small knife (karda, I think) so that itself may show something of the design.

 

[Cliff Stamp]

a flat ground 1/8" blade should perform as well as a hollow ground blade of thinner stock.

It could, depending on the nature of the grinds and the material being cut. Some hollow grinds like Strider uses are quite shallow and thus leave a much more obtuse profile than a full flat grind. When the grinds are of similar heights, the hollow grind should cut better if it is done in relief style and the material doesn't crack or split dramatically when being cut. Ref :

http://www.physics.mun.ca/~sstamp/images/grinds.xfig.gif

Note the hollow grind on the end, is basically a flat ground blade with too scoops cut out of it (Japanese hollow grinds are typically of this nature). This will directly increase the cutting performance on most materials as it drastically reduces sticking. This is what I meant in the above comment about needing hollow grinds on thinner stock as otherwise they can jam in vegetables.

The hollow grind in between the flat and convex on the other hand, will perform very well at shallow cuts as the edge profile is very thin, but as the blade is pushed through the material it can wedge badly at the top of the grind. Note how this can't happen with the hollow grind on the end. Note as well that grind doesn't have the extreme level of edge fragility either.

-Cliff