Handles: Power vs. Speed

[the possum]

I saw this brought up again recently in another thread, and have read about it in the past. Some have said the two above attributes can be compromised one way or the other by changing the amount of curvature in the handle.

Please explain.

 

[Lorien]

I think that your power comes when the but of the handle drops below the point of the knife, an exaggerated example would be a khukuri. Heavy on the downstroke, and difficult to control the tip. Lots of shearing force.

Speed comes when the butt of the handle is more in line with the point, an exaggerated example would be a dagger. The tip is more controllable for slashing and stabbing movements become effective, but far less power on a swing. Not much shearing force.

A leaf shaped blade can provide both power and speed, but would be fairly heavy and wide.

When the tip of the blade is above the butt of the handle, like a sabre, does that equate to higher speed? More shearing force in a cut?

 

[Lorien]

I'm surprised this thread hasn't received any other input

 

[Kevin Jones]

Hey man. You told the story. :thumbup: There's nothing left to say.

 

[Lorien]

huh. I thought someone might start piping off on angles and whatnot. I was hoping to learn a bit on this topic. My interests really center around things like ergonomics and physics. Were are the scientists?!

 

[Gene Martin]

I believe blade speed comes from a handle heavy knife. Since the weight is to the rear, the blade is quicker. That's pretty much regardless of handle shape, within reason. A blade heavy knife is slower but has more hacking power to it.

That's my understanding, anyway.

Gene

 

[the possum]

I was also hoping to get a little more input, because I'm still a bit puzzled by the way this idea was presented. I think I first saw it mentioned in a magazine article about competition knives, and if I remember correctly, it was simply said that straight handles are for speed while curved handles give more power.

I took this to mean they were talking about the handle shape only- they didn't say anything about blade shape or weight (as Lorien seemed to be talking about), nor about mass distribution through the blade vs. handle (as proposed by Gene). It sounded more like they were generalizing. As in, if you took the exact same blade, and mounted a curved or straight handle to it, without changing the balance, and without drastically changing the general design of the handle. (i.e., just bend it a little)

So I guess I'm having trouble visualizing this, since to my mind, speed is power. If you can swing the exact same blade faster, then naturally that blow should be more powerful.

I can think up many different tangents or possibilities of what they could have been talking about, and maybe just chose their words poorly?? But there's the chance that a valid idea has somehow managed to escape me for all these years, so I'd like to hear an explanation that sounds logical before doing mental gymnastics to come up with something that jives with my own experience and learning. Any further input welcomed.

 

[JParanee]

Lorien summed it up nicely with his description. You ponder that speed should equate to power but you can not forget about momentum a light fast blade although easy to pick up speed can not compare to a heavier blade with weight that might be slower to change direction and get moving but will have more power and hit like a freight train. I have a few fighter bowies that are a nice combination they feel light in the hand and alive. they have a slightly dropped handle and some weight in the blade and seem to carry a power stroke well. It is always a compromise betwen speed and power that's why I keep buying these dam knives looking for the perfect one.

 

[396vette]

I believe blade speed comes from a handle heavy knife. Since the weight is to the rear, the blade is quicker. That's pretty much regardless of handle shape, within reason. A blade heavy knife is slower but has more hacking power to it.

That's my understanding, anyway.

Gene

IMHO,from personal experience not physics mind you I would agree with this point.
That would probably be one of the reasons for skeletonized handles- to get the weight out of the handle. Just an opinion however, and we all know what that's worth!:foot:

 

[Doug C]

I have a few fighter bowies that are a nice combination they feel light in the hand and alive. they have a slightly dropped handle and some weight in the blade and seem to carry a power stroke well.

Joe,
Does your Bagwell fit in this category ?

Doug

 

[RogerP]

The responses posted by Lorien and JParanee pretty much accord with my understanding of the issue.

Roger

 

[Lorien]

Here's an example, http://www.valiantco.com/java/GolokJonggolM.JPG, of a straight, fairly narrow blade profile that generates lots of power due to the curved handle. I have this and use it lots. The curved handle angles the blade in such a way as to create a lot of shearing force. By this I mean that as the object to be cut is hit, it is essentially riding up the ramped edge that the angle between the blade and handle creates. If that makes any sense. It is blade heavy, and this is the other element that creates 'power'.

Momentum is a powerful force indeed, and is difficult to stop as the weight increases, making a blade less easy to control.

When the handle is curved and the blade is straight, you lose some power compared to a knife like this, http://www.thekhukurihouse.com/catalog/enlarge.php?id=313736f87&image=left,
where the blade is curved and the handle is straight. However, the tradeoff is that the blade can twist laterally more easily.

I agree that a handle heavy knife is easier to control, interrupting the momentum mid movement is not difficult because the weight of the blade is not effecting your wrist and robbing energy arresting the movement.
Anyway...yadayada. Time to go thrash myself and my bike for awhile on the mountain. I'll be bringing this; http://www.valiantco.com/java/GolokJagal.JPG should there be there any trails need clearing.:thumbup:

 

[Kevin Jones]

The responses posted by Lorien and JParanee pretty much accord with my understanding of the issue.

Roger

Mine too.

Here's an example. This Gamemaster is designed for good power for cutting through bone and cartilage.

This is the most functional hunter I have handled considering it's comfort in hand for extended use and design to suit task.

 

[Broos]

When you say power and speed, I think of chops or cuts made with a swing. When doing this, how much of the work of cutting is delivered by the kinetic energy of the strike, and how much is delivered by the user while the media is being cut?

Like some sports, is the most power delivered by a soft kind of loose grip? A powerful cut can be made like this (just like a good forehand, or drive).

Or do the most powerful cuts involve actually delivering forward force to the cutting blade during the cut? I can see this with a two handed type blow with a sword (or a hockey slap shot), and I think you can deliver this force if you time the wrist snap right before the edge impacts. A large sword with a weight at the handle end (is it called a finial?) could deliver additional energy to the cut by adding additional momentum around the pivot point, too. I think that the best cutters probably have some more going for them besides just kinetic energy - they have some way to time their strike to hit right when they are able to impart energy from their body into the cut, also.

The kinetic energy part is easy - the energy delivered for any given knife is simply a function of velocity. Your coordination, arm speed, and wrist strength is going to be the major factor in this.

Does one handle angle allow you to obtain higher velocity than another? Or does the handle angle allow you to better deliver energy from your hand into the cutting edge during the cut? I think it would be difficult to show how you can generate more velocity with a slightly bent handle than you could with a straight handle from a purely scientific basis. It's going to come down to skill, ergonomics, and comfort ruling this decision.

I'll bet there are a lot of members here who could give you good information on this based on their experience, but I don't know if that experience will hold true for every user. It would be interesting to explore further.

 

[JParanee]

Joe,
Does your Bagwell fit in this category ?

Doug

Yes all the Bagwell's I have fit in this category very nicely. All have stag handles with a curve and taper from but to guard add the popcorn and you could stick your hand in STP and still swing hard. The blades are 5/16 and they balance very well are fast in the hand and have the weight to have plenty of power. I have knives that are quicker and I have knives that are I guess you would say better choppers or cutters but in my opinion from what I have and have seen they are hard to beat on a feel performance level for a fighting bowie

 

[RogerP]

Yes all the Bagwell's I have fit in this category very nicely. All have stag handles with a curve and taper from but to guard add the popcorn and you could stick your hand in STP and still swing hard.

Funny you should mention that - when I ran through testing of Dan Farr's various competition cutters, he liberally slathered up a couple handles in mineral oil and had me chop the 2 by 4. Now, I wasn't swinging real hard, but I was cutting wood. It's real instructive of how a handle wants to move in your hand and how to design it not to.

Kids, don't try this at home.

Roger

 

[JParanee]

I am very fond of stag handles for the grip they give I also like the style of say Jason Knight and Matt Lamey type big back end flowing type for the grip they afford. And a well done tapered coffin handle gives a good grip to. The stag is a bit ruff for extended chopping but for grip I think if done right meaning enough taper from back to front sure does stay in your hand


BROOS I agree I always get a better cut with a knife if I keep a loose grip and I guess you would say snap cut thru the target tightening my grip is what gives the snap and imparts so much speed in the cut. In effect letting speed momentum and the edge do the work you just have to maintain your angle and draw through the target not chop it. This of course would depend on the media as in cutting thru a rope or chopping a 2 X 4 both would in my mind be different types of cuts and would need to be done accordingly one is a chop one is a cut

 

[Doug C]

Thanks Joe.:thumbup:
I handled one very briefly,at Ohio Gun & Knife Show in Niles but the gentleman had zero interest in parting with it.

Doug

 

[the possum]

Thanks all for chiming in. Some thoughts...

You ponder that speed should equate to power but you can not forget about momentum a light fast blade although easy to pick up speed can not compare to a heavier blade with weight that might be slower to change direction and get moving but will have more power and hit like a freight train.

I pretty much agree with what you're saying, however, that's not what I was talking about. Or at least, I think they weren't talking about anything to do with blade weight. (but that's why I'm here asking for clarification) See my post directly above yours.

IMHO,from personal experience not physics mind you I would agree with this point.
That would probably be one of the reasons for skeletonized handles- to get the weight out of the handle.

For what it's worth, in general terms I disagree with what Gene said, and so do at least some of the competition guys. I think it was Daniel Winkler who has said several times to taper the tang (reduce its weight) for balance and speed. That is, in this case, the blade is faster and more natural to manuever when the balance is shifted forward. I have written much on this subject in the past; probably in the review and testing subforum.

Here's an example, http://www.valiantco.com/java/GolokJonggolM.JPG, of a straight, fairly narrow blade profile that generates lots of power due to the curved handle. I have this and use it lots. The curved handle angles the blade in such a way as to create a lot of shearing force. By this I mean that as the object to be cut is hit, it is essentially riding up the ramped edge that the angle between the blade and handle creates.

I was also wondering if this is what they were getting at- the curved handle changes the angle the blade/edge is presented to the target. But I'm still not sure why that would slow down your swing. ? I do agree that the curved handle forces the blade into more of a straight shearing cut, as opposed to the "draw cutting" that is easier with a straighter handle. I disagree that there is much riding up the edge toward the handle, at least from what I've seen messing around with my khukri. But even that only really works if you're striking way back on the edge in the curve, so right off the bat you're sacrificing some power that could be had by hitting further out.

Momentum is a powerful force indeed, and is difficult to stop as the weight increases, making a blade less easy to control.

When the handle is curved and the blade is straight, you lose some power compared to a knife like this, http://www.thekhukurihouse.com/catal...f87&image=left,
where the blade is curved and the handle is straight. However, the tradeoff is that the blade can twist laterally more easily

Again, they didn't sound like they were talking about changing blade curvature and weight (i.e., changing everything until you have an entirely different knife); only handle curvature. I don't recall seeing any of the competition guys using khukris lately.

I agree that a handle heavy knife is easier to control, interrupting the momentum mid movement is not difficult because the weight of the blade is not effecting your wrist and robbing energy arresting the movement.

Without wasting a bunch of bandwidth here, in short I think it would be easier to say that "handle heavy" vs. "blade heavy" is too simplistic an approach.

This Gamemaster is designed for good power for cutting through bone and cartilage.

That knife was designed for fast and powerful chopping?

When you say power and speed, I think of chops or cuts made with a swing.

Yes, sorry to Kevin above; I should have made that more clear from the start.

Or do the most powerful cuts involve actually delivering forward force to the cutting blade during the cut? I can see this with a two handed type blow with a sword (or a hockey slap shot), and I think you can deliver this force if you time the wrist snap right before the edge impacts. A large sword with a weight at the handle end (is it called a finial?) could deliver additional energy to the cut by adding additional momentum around the pivot point, too.

At least regarding one handed stuff, the longer the blade gets, the less leverage you have on the tip. You're relying more and more on the blade to do all the work since your hand/wrist doesn't have the leverage to add much power during the cut. (this is why we chop in the first place) I think "pommel" may be the word you were looking for. Thanks for mentioning the pivot points in relation to it. I've often wondered why the competition guys don't make use of this more.

Does one handle angle allow you to obtain higher velocity than another? Or does the handle angle allow you to better deliver energy from your hand into the cutting edge during the cut? I think it would be difficult to show how you can generate more velocity with a slightly bent handle than you could with a straight handle from a purely scientific basis. It's going to come down to skill, ergonomics, and comfort ruling this decision.

This is exactly what I'm wondering. Either the handle is shaped to allow your hand to apply maximum power, control, and speed to the knife, or it isn't. (well, basically.) I have no doubt this will vary by individual for the reasons you mentioned.

Maybe I'm making much ado about nothing here. If anything it's beginning to sound more and more like I misunderstood what the authors of those comments were getting at, and it's really nothing out of the ordinary at all. But either way thanks all for a lively discussion.

 

[Kevin Jones]

Chopping ability is only one function of a knife that's affected by it's ergonomics. A Skinner/hunter as mentioned above, speed is very important as to a fighter's effectiveness in use as a weapon etc..