Does a curved blade chop better than a straight one?

[R.H.Clark]

what's your opinion? I've been making some very curvy choppers lately and I think the curve helps a lot.My thinking is that a curved blade will facilitate the draw cut more easily during a natural chopping motion. The curved blade will also have less blade area making initial contact with the surface to be cut therefore cutting deeper with less force.

What is your experience? Are there any drawbacks to a curved blade chopper other than maby ease of batoning? Here is a picture of my chopper design.http://

 

[Calebklyne]

First off that is one awesome lookin blade but it would seem to me like it wouldn't bite the same as a straight blade would, but I don't have a lot of experience with choppers

 

[Moosez45]

I always think a curved blade is better for slicing, the natural motion to want to keep steel to flesh, is facilitated by the curve, ie. katana. For chopping, I always go for a straight blade, broader area of contact. That choppa you got goin' on looks sweet, and there is alot to be said for force over a small area (curved choppa) vs force over a larger are (straight blade). Figure this, 10lbs of force spread out over 1", vs 10lbs of force spread out over 3". The 1" area is going to bite deeper, but the 3" area will cover more ground (wood) each strike. I dunno, seems like a wash in my mind. What do you think, you designed it, how does it chop? Moose

 

[R.H.Clark]

First off that is one awesome lookin blade but it would seem to me like it wouldn't bite the same as a straight blade would, but I don't have a lot of experience with choppers

These seem to chop very well for me.I can't decide though if it is the heavy blade,the blade forward of handle design,curved blade,grind,or maby a combination of all.Just trying to think it through so I can make adjustments if necessary.

 

[Kenon Rain]

I put a long curve into all of my blades.. it's just a good idea in my book..

I've experimented a lot, and while radical curves do do extremely well for slicing, not much of one is needed for chopping.. Now, if the thing you were chopping were a flat surface with no arc to it, a curved blade would smoke a flat.. It's all about the contact between the edge and materials..

one thing I will say though.. Kukri style knives seem to just suck for everything besides soft targets.. I can never get them to perform as well as a straight or whole length curve..

 

[Thomas Linton]

I have a number of axes and most were made with a curved edge. Most were also made to deal with North American hardwoods.

 

[barrabas74]

I have a number of axes and most were made with a curved edge. Most were also made to deal with North American hardwoods.

I was just thinking that. Most of my Axes have a curved Edge and if you Blew that edge up to 9 inches well....you might get something like first post

I bet the curve on that is almost identical to one of my GB's. If you were to remove the handle at the plunge line and add steel out behind it and a giant Hickory staff you'd have a big axe...I have a vivid imagination

 

[untamed]

Your design actually reminds of an old design or more appropriately, "ancient" would be a better description: the Egyptian khopesh.

I'm not so sure about the perceived "heft" but I think that since it moves the cutting edge forward, it essentially enlarges the sweet spot on to a much larger cutting area as compared to that of a straight edge. This also could mean that the arc of movement of the swing or chop (of your arm) could be more "compact" than on the straight edge making it feel more "efficient" as a chopper/slicer again compared with a straight edge.

 

[Shann]

Heck yes, curved blades chop great. The khukri is a great chopping knife and it is definately a curved blade, although curved the wrong (right?) way.

 

[R.H.Clark]

Untamed
Thanks for the pictures of the Khopesh.It just goes to show again that there is nothing new under the sun.

Also, thank you guys for reminding me that axes have curved blades.

 

[kgd]

Somebody already mentioned it, but the face of an axe almost always has a pronounced curve to it and for good reason. It was also mentioned already that the curve focuses the force on a smaller contact area. This serves the purposes of allowing for deeper bites and eliciting chips/chuncks of wood flying out from the strike area. If like an axe, you are chopping things that would not be cut through in a single strike, then that curve is going to help you break up material to create a wedge faster and more effectively.

Alternatively, I think that if you are going for the cut through in one stroke thing, then weight distribution and reach are more important considerations. For the machete's, I prefer the Latin profile which is mostly flat.

 

[AF]

The curve of a khukuri would seem to work better than the curve on the above knife.

 

[R.H.Clark]

The curve of a khukuri would seem to work better than the curve on the above knife.

I appreciate your opinion but can you explain your reasoning? I am still experimenting and trying to tweak the design.

 

[OwenM]

edit: I see kgd already simplified this while I was typing all this stuff!

The curved blade will give greater penetration, but in a smaller area. The larger the portion of the edge involved in the chop, the more difference you'll see with that "positive angle".
All other things being equal, it will perform better compared to a straight edge on harder materials due to concentrating the force of the chop into a smaller area.
Same is true of thicker materials that involve a greater percentage of the edge, because the edge will be introduced to the material being cut at different angles and depth along its length.
This allows it to penetrate without binding as much as if the entire edge was at the same depth.
|| vs. )| It's easy to see why the curved edge will have less resistance, and penetrate deeper.
That's why we chop notches instead of straight through something, and why a felling axe(whose entire edge length will be enveloped by the material being cut) has a continuously curved face.
All kinds of variables in chopping, from the knife's blade and edge geometry, primary grind type and geometry, overall weight, momentum/power, angle of the handle in relation to the blade, ergos, etc. and then the material being cut's width, depth, and consistency which is why I said "all other things being equal" and narrowed the "increased performance claims" specifically to harder or deeper cuts.
More involved than most people are going to want to get, but it's always interesting to look at what happens when the rubber meets the road.

 

[AF]

I appreciate your opinion but can you explain your reasoning? I am still experimenting and trying to tweak the design.

I think of an upswept blade as better for slashing than chopping. I think of a khukuri shape as better for chopping.
Also, I agree with people saying a curved edge with smaller contact area will bite deeper. But if you're talking about a knife (rather than an axe) that is going to be used to chop relatively small diameter branches, I don't think it matters much.

 

[hollowdweller]

I think it depends on how curved it is and what you ar chopping.

 

[a.l.hare]

I would think the curve helps make sure the cutting edge makes direct contact with the wood when chopping. Most pieces of wood are naturally uneven, and I would think the swing would change every time due to body mechanics. Unless you were using the straight blade like a guillotine, the curved blade should be more efficient because of the arc motion of the swing.

No science....just conjecture
Alan

 

[Ravaillac]

A few ideas:

convex curve (like parang) help focus impact on a small part, but I'm not sure it is that important (khukri are exactly the opposite and are still good choppers).

Curved blades means means weak spots (tips) are nowhere near impact.

Draw cutting is generally considered better than pure push cutting, so it helps to have your cutting edge angled (see guillotine), although the various explanations I've seen for this are not consistant and not always so good.

I guess the angle make the blade slide while it push-cuts making it partially a draw cut.

That said straight edge choppers can work fine too as seen with japanese hatchets:

http://www.ehamono.com/washiki/tukasa/img/ajikataya/sirosaya210r-1l.jpg

 

[Thomas Linton]

I you lay a typical hand axe on top of a typical khukuri, you will find that the sweet spot on the khuk is just about where the edge on the axe falls +/1 a bit. Just a different way to get that curved edge, with a proper angle of attack for shearing effect, in the proper relationship to your hand.

 

[ElSitherino]

I think it should be kept in mind that many khukiris have two opposing curves. The first, more noticeable curve in which the end of the blade leans forward. The second being the deep down belly that sweeps up to the tip. The initial curve gives the blade a forward balance that is good for making an efficient chopping/cutting motion, while the second curve of the blade edge gives a great focus for an effective chop. What OP has posted is simply a concentration of the khukuri's end, which is similar to what we see in the newly produced H.I. Farm Knife and many other variations of chopping/sweeping motion blades (goloks, daos, khopeshes, etc.).