Why curved not straight?

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wacki

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Sep 12, 2009
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What's the advantage of a curved blade over a straight blade?



Seems to me that a curved blade would be heavier for same reaching distance. There's good & bad here. Curved blade may give you shorter swing windup space albeit not by much. Straight blades make contact later so you have more room to gain speed....
 
Ta2 is correct.
In more specific terms, the curve creates more edge area with which to cut, for example draw cuts. One pull cut will traverse a longer distance over a curved edge than a straight one. Also the belly of a kuk specifically, will reach down into the target material, and provide additional downward cutting pressure. Curved toward the weilder swords, like a scimitar, require a curved sweeping draw cut and slash, to keep edge contact with the target. But if you ever use a heavily curved blade like a Talwar, British Light Calvary 1792, you will see that the slicing, curved draw cut becomes a natural motion with these curved blades. Just like slicing a steak off of a big ole' prime rib.

During a chop it is a little different.. *Less* of the edge hits the target at one time, increasing the pounds per square inch at the edge. (same force, on a smaller curved contact area. This contact area increases as the chop bites ever deeper into the wood till it stops. You can imagine that a straight blade with no curve would hit the target with all the edge that makes contact at once <pang!>. And this large contact area makes it harder to draw/rock the blade out and across the target after a chop.

I have always been told "The power of a knife is in the cut." and my experience so far has proved this phrase correct. Max work for minimum effort.
 
Ok now I'm wondering why were broad swords so popular? I would think the knights of Europe would of taken advantage of the curve.... especially since they knew about them from the crusades.
 
wacki said:
Ok now I'm wondering why were broad swords so popular? I would think the knights of Europe would of taken advantage of the curve.... especially since they knew about them from the crusades.
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Metalurgy in Europe was way behind the metallurgy in the Middle East and Asia. Damascus steel was a very advanced metal for the time, and it became legendary during the crusades because it out performed the blades made in Europe.
 
Shinook said:
Metalurgy in Europe was way behind the metallurgy in the Middle East and Asia. Damascus steel was a very advanced metal for the time, and it became legendary during the crusades because it out performed the blades made in Europe.
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Yep.. alot had to do with economy.. and having to utilize industrious methods to make those weapons use the best qualities of the steels that they had. And their steels weren't as consistently fine at the time, so they had to make straight, thick spines on their weapons.. and easy to sharpen and maintain.. etc.
You also have to remember, that there was wootz.. and with this, true damascus steel was made.. and it gave the people in the middle east to asia.. the 'edge' for awhile.

This thread may be moved to the cantina for continuing discussion.
 
Great responses guys. I appreciate it.

Ok... since steel quality was the reason now I'm wondering why Swamp Rat and many other high end choppers are straight edged. I was thinking of a Scrap Yard chopper but now I'm thinking Himalayan Imports would be better.
 
Strait edges have some benefits too, they are easier to produce and maintain for starters. Making a sheath for a strait knife is much easier that making a sheath for a Khukuri. Strait blades are also easier to stab with. But for chopping, it's difficult to beat a Khukuri. A Khukuri is a very good knive for many different tasks.
 
wacki said:
Great responses guys. I appreciate it.

Ok... since steel quality was the reason now I'm wondering why Swamp Rat and many other high end choppers are straight edged. I was thinking of a Scrap Yard chopper but now I'm thinking Himalayan Imports would be better.
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I think it became traditional, cultural, and personal preference after awhile like everything else. Intended use, and normalcy in your everyday environment will tend to shape your preferences and biases.
As an example, the gentle graceful curve of a japanese sword, was an aftereffect of the tempering/hardening process. The samurai sword as we know it, evolved from straight longswords. Now, if someone makes a showpiece (modern samurai swords are outright banned in many countries unless made in the traditional old style) they will always make a gently curving sword. Same as the tourist style Khukuris, when it is made just for looks and not to be used.

You tend to stick with what you know, and what has been proven to work for so long.

Hundreds of years of Gurkha's, Samurai's.. and Knight's can't be wrong.. :-)
 
Shinook said:
Strait edges have some benefits too, they are easier to produce and maintain for starters. Making a sheath for a strait knife is much easier that making a sheath for a Khukuri. Strait blades are also easier to stab with. But for chopping, it's difficult to beat a Khukuri. A Khukuri is a very good knive for many different tasks.
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sort of...
A curved blade "can" thrust just as well as a straight blade. And the curve gives you options on getting behind the guard.
The "down thru the collar bone" or "up into the belly" thrusts of a Shamshir
http://www.vikingsword.com/ethsword/shamshir/index.html
comes to mind particularly. But thrusting with a curved blade takes practice and you need to know your blade.

Even after metallurgy issues, many military swords were straight because they are cheaper to produce. and training is minimal, beyond basic thrust and hack... they aren't training ninjas in the Calvary.
Often many cavalry trooper swords were curved so you could make a pass cut, without getting your sword stuck at full gallop. You can imagine that would likely unseat the trooper. Stabbing from horseback is best done by lance. IMHO. Read about what happened at Waterloo.
 
Might as well continue to weight in on this :)

1) Curved blade on the Khuk's is curved forward. In addition to what others have mentioned this means that you actually continue to accelerate through the swing after contact due to the earlier point of contact. Try hitting a tree with a machete versus a khulkri. you'll find that the machete stops almost instantly after contact, while the Khukri will stop significantly further into the limb. Part of this is because of the weight, part due to the difference in the pounds per inch and surface area mentioned above, and part because of the physics change in velocity and acceleration as a result of the effort you are putting into the swing. All kinda cool.

2) Medieval knights. Swords were designed to be used from horseback. A forward curved back such as the Falcata, Khukri, etc. are not as effective from horseback. This was mentioned above with the inability to make sweaping cuts. Scimitars and such curved backwads were increadibly useful from horseback as it allowed for a clean cut that helped prevent hte sword being wrenched from the riders hand on contact by allowing a more gradual distribution of force. Just look at a cavalry sabre. Additionally, while sweeping cuts were great for mowing down peasants, against armor they were effectively only clubs. Something with penetration was required. It is difficult to make something such as a sabre or khukri that is curved and long enough to be effective enough from horseback equally effective at thrusting. Was easier with a straight balde.

3) As said, straight was and is easier to produce and maintain, economics, and all that other stuff :)
 
I'm really starting to think I should skip the swamp rat chopper and stay with the HI imports khulkuri.
 
But, if you want to reach out and touch them with a thrust, any sword is inferior to a spear, pike, or lance.
The history of warfare proves this definitively. From Alexander to Waterloo. And spear heads are even cheaper to produce...

For mowing down unarmed and unarmored peasantry or artillery batteries or unmounted infantry, the mounted saber is tops due to speed and maneuverability.

The kukri has always been a tool that can be pressed into use as a weapon, not the other way around. IMHO. But being able to clear trails, and build defences, and survive in the bush still makes the kukri part of the modern infantry weapons system right? Even if you don't ever apply it *directly* to the enemy.
 
The Swamp Rat is an awesome one for what it does. Both the Khukuri and the Swamp Rats and the like.. have their place, and are versatile.

Just have to match the tool with the specific use.. as broad as it may personally be.
 
Love your new tag Ta2.

"I don't collect. I use. I throw away boxes.. open and trash packing.. modify everything. I break warranties minutes after I purchase anything, to make it MINE, not for an investment."

I feel the same way.
Half the fun of HI knives is that you get a solid hand-forged blade that isn't so expensive you feel guilty about working on it.
 
Thanks! I use it as a semi-disclamer :-)

All my khukuri's get nice and used.. and I do maintain them regularly.. maybe more than most people would. But they sure earn their place.

I took a $1200 dollar pre-loved Jay Fisher combat knife made to the original owners specs.. fossilized scales and all.. IMMACULATE.. with me to the 'stan twice.

It did what I asked it to do, and I was ready to bet my life on it if it came to that which is why I acquired it anyway.

And it is definitely now mine, and looks like it's seen the world :-)

No safe queens here haha.

I can't wait to get my Winkler 'hawk.. it's got big shoes to fill...
 
A properly setup axe has an edge that angles in towards the handle at the heel (bottom) of the bit (edge). This pulls the "work" into the blade when cutting.

Place a khukuri on top of a hand axe. The sweet spot of the khukuri typically parallels the edge of the good hand axe. So the khukuri also pulls the work into edge, increasing cutting depth.

Inward angled sword blades, like "running water," central heating of buildings, postal service, and domed roofs, were used in Europe before the "Dark Ages." Civilization does not proceed ever upwards.
 
Like an ax or hawk, the khukuri's strength is power for offense. A straight blade is generally more balanced. Not as much power, but responsive. There are exceptions, but the key IMO is the analogy with the ax/hawk, which are widely known for offense.
 
wacki said:
I'm really starting to think I should skip the swamp rat chopper and stay with the HI imports khulkuri.
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Way oversimplified there. Don't overlook a stellar group of knives because they are not the same blade shape as a certain sword type.

Also important to note, typical european swords were double edged, which lends its self to straight edges.

Also chopping and slashing are different. If I take a log and go to chop it in half with my large chopper, I am not making the same kind of stroke that I would use trying to cut a person with a curved sword.

Swamprat, Busse and Scrapyard make stellar knives. Fantastic steels, with perfected, very involved heat treat protocal. They use very accurate cnc equipment and make precision machined knives.

HI knives are completely different. They are making hand made products, in traditional designs, out of servicable capable spring steel. They are using more primitive methods, producing a very personalized unique products. It is a hand made product in the most basic sense.

The only common element for the two types of production is that they both make cool knives that are worth owning.
 
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