The Curve Factor: A Huge Advantage In Some Cases

Discuss Spyderco's products and history.
JD Spydo
Member
Posts: 16186
Joined: Tue Sep 28, 2004 7:53 pm
Location: Blue Springs, Missouri

The Curve Factor: A Huge Advantage In Some Cases

Postby JD Spydo » Sat Nov 24, 2018 1:12 pm

Well we've had enough Hawkbill threads to fill our quota for a while>> and we've beat the Reverse S blade subject unmercifully as well. In some ways we've really just begun to closely examine the pros and cons of Reverse S blades. But I do think we've come to a consensus that blade designs with CURVE in them do offer some distinct advantages ( especially in Spyderedge). But not limited to Spyderedges as some skinner type models have proven to be great in PE as well.

Even standard blade designs with a "belly" factor to them ( like the C-60 Ayoob for instance) have always been your better skinning knives and to some degree have offered a lot in the area of self defense. But one thing these aforementioned great ( Mostly Spyderco) blades have in common is their "curve factor".

Also I think it's very fair to say that Spyderco's Spyderedges ( their own patented serration patterns) tend to really shine the brightest and perform the best on blades with "curve" in them.

When I first explored the world of Hawkbills I was amazed at the difference between SE & PE Hawkbills. They are literally a universe apart from the standpoint of capabilities and advantages that SE blades offer with a "curve factor". Like I said in another thread I'm to the point now to where I have virtually no use at all for a plain edged Hawkbills or PE Reverse S blades either for that matter. And how interesting it is that a curve can be a major advantage in different edge types or in some cases or can actually hinder your cutting jobs.

I'm still wanting to see what a super Recurve model like the ULIZE will perform like with a good set of serrations. OK boys and girls let's talk about this "curve" factor and how Spyderco and how we, the end line users can take advantage of it.

Bill1170
Member
Posts: 1739
Joined: Tue Oct 20, 2009 7:34 pm
Location: San Diego North County

Re: The Curve Factor: A Huge Advantage In Some Cases

Postby Bill1170 » Sat Nov 24, 2018 1:41 pm

Consider the one handed curved pruning saw, which cuts on the pull stroke. Pulling the saw towards yourself forces the teeth to bite into the wood. Pulling is a much more powerful muscular action than one can perform pushing a blade laterally into the work, especially at arm’s length. Hawkbills take advantage of this same dynamic.

JD Spydo
Member
Posts: 16186
Joined: Tue Sep 28, 2004 7:53 pm
Location: Blue Springs, Missouri

Re: The Curve Factor: A Huge Advantage In Some Cases

Postby JD Spydo » Sat Nov 24, 2018 4:09 pm

Bill1170 wrote:
Sat Nov 24, 2018 1:41 pm
Consider the one handed curved pruning saw, which cuts on the pull stroke. Pulling the saw towards yourself forces the teeth to bite into the wood. Pulling is a much more powerful muscular action than one can perform pushing a blade laterally into the work, especially at arm’s length. Hawkbills take advantage of this same dynamic.
That's a really good but yet simple analysis of the principle of pull cutting in general. Circular saw blades like on a DeWalt power saw also come to mind as well.

Even when you consider the Cricket and Dodo models it's incredible how much more a curved blade of that tiny size is capable of.

User avatar
Pelagic
Member
Posts: 1647
Joined: Fri Apr 27, 2018 5:49 pm
Location: East Coast/Nomadic

Re: The Curve Factor: A Huge Advantage In Some Cases

Postby Pelagic » Sat Nov 24, 2018 6:07 pm

It's almost like making the entire blade a serration. Similar principles at work.
Deadboxhero wrote:
Thu Apr 04, 2019 9:25 pm
8dps is going to be sharper then 15dps.
Nate wrote:
Thu Apr 04, 2019 4:32 pm
You're the lone wolf of truth howling into the winds of ignorance
Doeswhateveraspidercan wrote:
Sat Jun 15, 2019 9:17 pm
You are a nobody got it?

User avatar
Evil D
Member
Posts: 19918
Joined: Sat Jun 26, 2010 9:48 pm
Location: Northern KY

Re: The Curve Factor: A Huge Advantage In Some Cases

Postby Evil D » Sat Nov 24, 2018 7:46 pm

Generally I prefer shallow bellies over sweeping curves, but ultimately it comes down to where the tip of the blade ends up in relation to the handle. So for example the Ayoob or Ulize get a pass because of their negative blade angle, but I can't live with something like a Lionspy where the tip of the blade is practically in line with the spine of the handle. The Sliverax is just about the perfect blade shape for 99% my needs. Other shapes are pretty specific situational advantages like hawkbills doing well at pull cuts or upswept tips doing well at skinning. It seems like most of the things I cut I do so while holding them in my off hand anyway so having a belly doesn't really make much difference unless I'm making cutting board cuts. For me it's far more important to have a bit of negative blade angle which seems to help give me extra leverage and control over the cut.
SHARPEN IT LIKE YOU LOVE IT, USE IT LIKE YOU HATE IT
~David

User avatar
SpyderEdgeForever
Member
Posts: 6258
Joined: Mon Jul 23, 2012 6:53 pm
Location: USA

Re: The Curve Factor: A Huge Advantage In Some Cases

Postby SpyderEdgeForever » Sat Nov 24, 2018 8:11 pm

I like both straight blades and curved. Curved definitely go more with the design we see in nature. I have heard that they make better utility and combat knives than straight blades.

User avatar
Tucson Tom
Member
Posts: 968
Joined: Tue Mar 28, 2017 10:19 pm
Location: Somewhere in Arizona

Re: The Curve Factor: A Huge Advantage In Some Cases

Postby Tucson Tom » Sat Nov 24, 2018 9:21 pm

It is almost spooky that this topic comes up, because I was spending some time earlier today thinking about knives with "belly". I recently picked up a Junction which is a fixed blade with a conventional shape with a lot of belly. Then I got to thinking about one of my common use tasks -- cutting the tape on boxes I get shipped to me. With a knife like the PM2, I use the tip -- it is pretty hard but not impossible to use the curve of the blade. But with a knife like the Junction, it is made to order to use the curved part of the edge. I've never skinned an animal, so those who have may comment, but I have to think that the same principles would apply.

I watched a video by Ernest Emerson of Emerson Knife, and he commented on the cutting power of a knife with belly in a tactical scenario, which surprised me and opened my mind to thinking about this "old fashioned" knife shape in an entirely new and positive way.

The business of using tip versus belly also strikes me from a point of view of (for lack of a better word) sturdiness. Using a pointed tip for everything puts all the wear on a minuscule part of the knife. Using the belly uses a longer and variable part of the edge, which just has to hold up better.

Well, there you have the current state of my thoughts on the subject.

User avatar
Wanimator
Member
Posts: 602
Joined: Fri Aug 29, 2014 9:40 pm
Location: Earth

Re: The Curve Factor: A Huge Advantage In Some Cases

Postby Wanimator » Sun Nov 25, 2018 12:51 am

Varies on how and what you're cutting.

JD Spydo
Member
Posts: 16186
Joined: Tue Sep 28, 2004 7:53 pm
Location: Blue Springs, Missouri

Re: The Curve Factor: A Huge Advantage In Some Cases

Postby JD Spydo » Sun Nov 25, 2018 3:30 am

Tucson Tom wrote:
Sat Nov 24, 2018 9:21 pm
It is almost spooky that this topic comes up, because I was spending some time earlier today thinking about knives with "belly". I recently picked up a Junction which is a fixed blade with a conventional shape with a lot of belly. Then I got to thinking about one of my common use tasks -- cutting the tape on boxes I get shipped to me. With a knife like the PM2, I use the tip -- it is pretty hard but not impossible to use the curve of the blade. But with a knife like the Junction, it is made to order to use the curved part of the edge. I've never skinned an animal, so those who have may comment, but I have to think that the same principles would apply.

I watched a video by Ernest Emerson of Emerson Knife, and he commented on the cutting power of a knife with belly in a tactical scenario, which surprised me and opened my mind to thinking about this "old fashioned" knife shape in an entirely new and positive way.

The business of using tip versus belly also strikes me from a point of view of (for lack of a better word) sturdiness. Using a pointed tip for everything puts all the wear on a minuscule part of the knife. Using the belly uses a longer and variable part of the edge, which just has to hold up better.
I also find it very interesting considering Ernest Emerson's ideal SD blade versus what our own Michael Janich deems to be the optimal SD blade. Because they are both at opposite ends of the spectrum with their methodologies. But neither one of them are wrong either. Again we sort of have a "Ford Vs Chevy" debate in a way because both guys make extremely good cases for their ideal SD blade setup.

I'm continuing to learn more about Michael Janich's Wharncliffe SD scenario whereas I also see the benefits in what Ernest Emerson brings to the table as well. But take the C-60 Ayoob model for instance it's at a constant "angle of attack" by it's mere design. Also the Ayoob model has been deemed to be one of the very best Spyderedged units that Spyderco has put out over the years too. Unlike Hawkbills designs like the Ayoob can do extremely well in both edge types.

User avatar
Evil D
Member
Posts: 19918
Joined: Sat Jun 26, 2010 9:48 pm
Location: Northern KY

Re: The Curve Factor: A Huge Advantage In Some Cases

Postby Evil D » Sun Nov 25, 2018 9:24 am

I think Michael Janich is looking at self defense from a perspective that most other SD guys haven't considered. He's looking at mechanical advantage, where a wharnie will cut with full force throughout the arch of a slash whereas a blade with a belly will cut with less force at the tip when slashing. Not all self defense relies on slashing but it's probably the most natural and fluid motion to make and a wharnie still stabs as well or better than other blade shapes. The beauty of a wharnie blade (for example the Yojimbo) is that when penetrating something, the slope of the spine forces the edge to cut which opens up a larger wound. The only design that's better in my mind is a double edged dagger but even it won't slash as well as a wharnie.
SHARPEN IT LIKE YOU LOVE IT, USE IT LIKE YOU HATE IT
~David

JD Spydo
Member
Posts: 16186
Joined: Tue Sep 28, 2004 7:53 pm
Location: Blue Springs, Missouri

Re: The Curve Factor: A Huge Advantage In Some Cases

Postby JD Spydo » Sun Nov 25, 2018 10:18 am

Evil D wrote:
Sun Nov 25, 2018 9:24 am
I think Michael Janich is looking at self defense from a perspective that most other SD guys haven't considered. He's looking at mechanical advantage, where a wharnie will cut with full force throughout the arch of a slash whereas a blade with a belly will cut with less force at the tip when slashing. Not all self defense relies on slashing but it's probably the most natural and fluid motion to make and a wharnie still stabs as well or better than other blade shapes. The beauty of a wharnie blade (for example the Yojimbo) is that when penetrating something, the slope of the spine forces the edge to cut which opens up a larger wound. The only design that's better in my mind is a double edged dagger but even it won't slash as well as a wharnie.
Those are some good points to consider>> although not all Wharnies are good for stabbing>> Oh yes the ones Mr. Janich has designed will cover that base for sure. But in some respects you could say a "sheepsfoot" blade is a type of Wharnie and that design woudn't help you much in a tight situation.

I just wish that Ronin II would have had better steel in it :( The very first Ronin with VG-10 I would take over that one myself.

But there are a lot of SD potentials in blades with "curve" in them. Again the Ayoob being an excellent example along with my beloved Chinook III.

User avatar
Evil D
Member
Posts: 19918
Joined: Sat Jun 26, 2010 9:48 pm
Location: Northern KY

Re: The Curve Factor: A Huge Advantage In Some Cases

Postby Evil D » Sun Nov 25, 2018 10:27 am

Sheepsfoot blades I think are generally designed with safety in mind to avoid stabbing so while they sometimes have a straight edge like a wharnie they're usually blunt tipped. Michael's wharnies are typically pointier than most too so they stab better than others.
SHARPEN IT LIKE YOU LOVE IT, USE IT LIKE YOU HATE IT
~David

JD Spydo
Member
Posts: 16186
Joined: Tue Sep 28, 2004 7:53 pm
Location: Blue Springs, Missouri

Re: The Curve Factor: A Huge Advantage In Some Cases

Postby JD Spydo » Sun Nov 25, 2018 10:35 am

Evil D wrote:
Sun Nov 25, 2018 10:27 am
Sheepsfoot blades I think are generally designed with safety in mind to avoid stabbing so while they sometimes have a straight edge like a wharnie they're usually blunt tipped. Michael's wharnies are typically pointier than most too so they stab better than others.
Yeah you're right about the "sheepsfoot" because it is a specialty type blade for rescue and first responder type jobs with safety in mind. Because if your going to try to extricate someone from a wrecked car you sure don't want to have to worry about injuring a person any worse they they already are while trying to free them.

Correct again on Michael Janich being a Self Defense Guru so to speak and it is reflected in his designs. I've always found it interesting that Mr. Janich seems to abhor serrated edges for almost any type of blade>> but especially in SD blades. I won't argue with him because maybe he sees something I just overlooking :confused:

User avatar
Evil D
Member
Posts: 19918
Joined: Sat Jun 26, 2010 9:48 pm
Location: Northern KY

Re: The Curve Factor: A Huge Advantage In Some Cases

Postby Evil D » Sun Nov 25, 2018 11:08 am

JD Spydo wrote:
Sun Nov 25, 2018 10:35 am
I've always found it interesting that Mr. Janich seems to abhor serrated edges for almost any type of blade>> but especially in SD blades. I won't argue with him because maybe he sees something I just overlooking :confused:

Well he's right because they do tend to snag fabric, even when very sharp. I like to think he's done enough testing to see a difference in how they perform. I wouldn't want the blade to snag on denim and yank the knife out of my hand, and I have no doubt PE will slice everything up when you hit someone with enough force.
SHARPEN IT LIKE YOU LOVE IT, USE IT LIKE YOU HATE IT
~David

husq2100
Member
Posts: 160
Joined: Sat Dec 27, 2014 4:43 am
Location: Gold Coast, Australia

Re: The Curve Factor: A Huge Advantage In Some Cases

Postby husq2100 » Sun Nov 25, 2018 2:03 pm

Bill1170 wrote:
Sat Nov 24, 2018 1:41 pm
Consider the one handed curved pruning saw, which cuts on the pull stroke. Pulling the saw towards yourself forces the teeth to bite into the wood. Pulling is a much more powerful muscular action than one can perform pushing a blade laterally into the work, especially at arm’s length. Hawkbills take advantage of this same dynamic.
An advantage I see in pull cutting for pruning saws is placing the blade in tension. Given most curved pruning saw blades are long in thin. Place them in compression and they are prone to buckling. By having the saw cut on the pull and placing it in tension this reduces buckling and makes for a smoother cut.

I could be wrong and has nothing to do with knives and the way they cut.

Im also not sure how a circular saw is an example of pull cutting???

JD Spydo
Member
Posts: 16186
Joined: Tue Sep 28, 2004 7:53 pm
Location: Blue Springs, Missouri

Re: The Curve Factor: A Huge Advantage In Some Cases

Postby JD Spydo » Sun Nov 25, 2018 3:38 pm

Evil D wrote:
Sun Nov 25, 2018 11:08 am
JD Spydo wrote:
Sun Nov 25, 2018 10:35 am
I've always found it interesting that Mr. Janich seems to abhor serrated edges for almost any type of blade>> but especially in SD blades. I won't argue with him because maybe he sees something I just overlooking :confused:

Well he's right because they do tend to snag fabric, even when very sharp. I like to think he's done enough testing to see a difference in how they perform. I wouldn't want the blade to snag on denim and yank the knife out of my hand, and I have no doubt PE will slice everything up when you hit someone with enough force.
There's one big exception to all of that>> and I'm in no way trying too disrespect Mr. Janich at all. But When Spydervile's Doc Snubnose did his meat test with the Spyderedged Ayoob the results were truy astounding. I hope Doc is OK I haven't heard from him in a while now but he tests all of this stuff too.

I still say that snagging can be remedied by going with a serration with a rounded/wavy pattern in stead of the spikey patterns that dominate most of Spyderco's folders. With the spikey pattern there is some problems no doubt.

Michael Janich
Member
Posts: 1565
Joined: Fri Sep 24, 2004 10:33 am
Location: Longmont, CO USA
Contact:

Re: The Curve Factor: A Huge Advantage In Some Cases

Postby Michael Janich » Mon Nov 26, 2018 6:38 am

Hey, All:

Thanks for a cool discussion.

For the record, I don't "abhor" serrated edges. From a utilitarian or rescue perspective they are great--especially if you do a lot of cutting on rope or webbing. They also work well on specific personal-defense knives like the Civilian and Matriarch because of the dynamics of the reverse-S edge profile. However, for my focused purposes--small, legal-to-carry personal-defense knives--plainedged blades work better for my needs. The primary reason is that they cut more efficiently through loose clothing based on my tests and my preferred cutting mechanics.

I used to think that "belly" was preferred in a self-defense knife because it provided a longer cutting edge and because that's what I read in all the books and articles I could find when I first got into this stuff. Based on that belief, I designed my first production knife--the Masters of Defense Tempest--with a Bowie-style blade and lots of belly. Then I decided to think for myself and started doing Pork Man testing. I realized that I didn't know as much as a thought...

For the record, the reason that the Ayoob (which I've also done cutting tests with) cuts well is that its negative handle-to-blade angle allows more powerful pressure into the target, which negates any effect that its belly might have. Curiously, Mas designed it that way to make it a better thruster, because it supposedly came closer to replicating the grip on a pistol (the TDI knife does the same thing). Ed Schempp, a man who really understands the dynamics of cutting, designs his knives with that negative angle to accentuate cutting power. In fact, most competitive cutting blades have negative handle angles and lack significant belly for that reason.

I hope this helps.

Stay safe,

Mike

JD Spydo
Member
Posts: 16186
Joined: Tue Sep 28, 2004 7:53 pm
Location: Blue Springs, Missouri

Re: The Curve Factor: A Huge Advantage In Some Cases

Postby JD Spydo » Mon Nov 26, 2018 3:19 pm

Thank you again Mr. Janich for another one of your most interesting replies :) I sure apologize for using an obvious wrong choice of words ( abhor :o ) but I did remember you stating on a couple of different occasions that Spyderedged blades are not an optimal edge choice for a self defense type blade. I just kind of got it in my head that you didn't really like serrations/Spyderedges>> I'll try not to jump to conclusions next time :o I'll tell you where I'm coming from and it's the same as you suggested as Spyderedges are ideal for utility type cutting jobs. And I couldn't agree with you more. I'm finding from so many sources that Spyderedged Hawkbill blades for instance tend to be a superb tool for lawn, garden, landscaping and to some extent working in a tree nursery or even fruit tree pruning on young trees. Curved blades with serrations just seem to have more utility uses than curved plain edged blades IMO.

And I do use my companion, full Spyderedged blade, sheepsfoot ( ATS-55 SE stainless RESCUE model) for pretty much only rough utility cutting jobs that pose a challenge for plain edges. The C-60 Ayoob is most definitely a really unique ergonomic wonder and I truly wish Massad Ayoob would do another design along those lines because it's just one of my all time favorite Spyders for just about any cutting job.

While we're on the subject of Spyderedges I'm wondering what your thoughts might be on different serration patterns. Most of Spyderco's utility folders have those rather "spikey" type blades whereas Spyderco's kitchen/culinary knives tend to use a more wavy and rounded type serration pattern. What are your thoughts on those two different serration patterns? Also your thoughts on serrated utility blades performing better with some type of curved blade ( Hawkbill for instance) rather than just a conventional type blade design?

Bill1170
Member
Posts: 1739
Joined: Tue Oct 20, 2009 7:34 pm
Location: San Diego North County

Re: The Curve Factor: A Huge Advantage In Some Cases

Postby Bill1170 » Mon Nov 26, 2018 11:38 pm

husq2100 wrote:
Sun Nov 25, 2018 2:03 pm
Bill1170 wrote:
Sat Nov 24, 2018 1:41 pm
Consider the one handed curved pruning saw, which cuts on the pull stroke. Pulling the saw towards yourself forces the teeth to bite into the wood. Pulling is a much more powerful muscular action than one can perform pushing a blade laterally into the work, especially at arm’s length. Hawkbills take advantage of this same dynamic.
An advantage I see in pull cutting for pruning saws is placing the blade in tension. Given most curved pruning saw blades are long in thin. Place them in compression and they are prone to buckling. By having the saw cut on the pull and placing it in tension this reduces buckling and makes for a smoother cut.

I could be wrong and has nothing to do with knives and the way they cut.

Im also not sure how a circular saw is an example of pull cutting???
Regarding that last sentence, while I’m not the one who suggested the connection between circular saw blades and pull cutting, I do have thoughts about it.

Circular saw blades for wood come in a range of geometries. The most aggressive tooth geometries are used for ripping solid wood, as for example in a tablesaw or handheld circular saw. These blades have teeth that hook into the wood and pull out a large chip (helps to keep the cut cool). While these teeth resemble a hawkbill blade in profile, they function as a chisel being brought to the wood at a large positive angle to scoop out a chip. Whereas a hawkbill knife uses its tip to initiate a cut which the rest of the edge continues, a flat ground (straight across the tip, common on dedicated ripping blades) ripping tooth severs the work ONLY at the tip, just like a chisel.

JD Spydo
Member
Posts: 16186
Joined: Tue Sep 28, 2004 7:53 pm
Location: Blue Springs, Missouri

Re: The Curve Factor: A Huge Advantage In Some Cases

Postby JD Spydo » Tue Nov 27, 2018 8:25 pm

Hey Bill1170 I like your analysis of a typical Circular Saw blade. I will also add that it is like a rotating Hawkbill Chisel. I think the more we dig into Hawkbill blades we will all realize that they are more prevalent in edged tool than we thought.

Even the Reverse S blades just operated at a much higher level than the plain edged. I at one time had one of the brown handled PE Matriarch Sprint runs. I couldn't even bring myself to ever use it>> or even try to because my older, original VG-10 SE Matriarch works well whenever I break it out. Again I just think if Spyderco would make Reverse S blades with a thicker tip they would be much more useful and still retain their self defense features as well.


Return to “Spyderco General Discussion”

Who is online

Users browsing this forum: Bing [Bot], Google [Bot] and 19 guests