"No unnecessary weight in the poll."

[FortyTwoBlades]

That comment is another example of conjecture or speculation, presented as fact: "would actually get surprisingly tiring..."

No, it's a matter of opinion. But in terms of fighting it all day it's just noting that repeated exposure to the force adds up. So forces that can feel inconsequential in low volume can sometimes end up creating enough fatigue over time for it to become of some significance. Or perhaps not, depending on the specifics.

 

[Steve Tall]

Which would actually get surprisingly tiring if you were working all day fighting it.

Ironically, this "tiring" comment is about the case of having a center of gravity that's closer to the bit (which can apply to poll-less axes when compared to axes with substantial polls).

 

[FortyTwoBlades]

Ironically, this "tiring" comment is about the case of having a center of gravity that's closer to the bit (which can apply to poll-less axes when compared to axes with substantial polls).

I'm not sure I follow...in a "7" balanced axe you won't experience any torque when the axle is at 0° to the horizontal (the center of gravity over the hand) despite the handle being at a skew to it. And perhaps I may have been misunderstanding your prior note--you're still talking about the CoG being moved forward with the edge/handle remaining in their original starting position in space, right? Sorry--juggling a lot of things right now so I read over it quickly.

 

[rjdankert]

. . .

For the case where the straight handle axis is aligned with the center of gravity, the torque ranges from 12 ft-lbs (at 0 degrees) down to zero ft-lbs (at 90 degrees), but it's not a linear decrease:

Degrees----Ft-Lbs
0----12.0
22----11.1
45----8.5
67----4.7
90----0.0

For the case where the center of gravity is moved 1 inch forward (toward the bit), the torque ranges from 12 ft-lbs (at 0 degrees) down to 0.3 ft-lbs (at 90 degrees):

Degrees----Ft-Lbs
0----12.0
22----11.3
45----8.7
67----5.0
90----0.3


Comparing these two cases, the torque increases when the center of gravity is moved 1 inch forward (toward the bit), and the increase in torque ranges from zero (no difference at 0 degrees) up to 0.3 ft-lbs (at 90 degrees):

Degrees----Increase in Ft-Lbs
0----0.0
22----0.1
45----0.2
67----0.3
90----0.33

With this method, we can quantitatively estimate (instead of just making educated guesses) for the effects of different locations of the center of gravity, etc. And the terminology and methods are the same as used by textbooks and other sources. I will gladly share the spreadsheet, or formulas, or run more cases, if there is interest in this.

I believe that in the third table (comparison) 22 degrees should be a difference of 0.2 (11.3 - 11.1).

Yes, please. I'd like to see the formulas used.

Bob

 

[Steve Tall]

No, it's a matter of opinion. But in terms of fighting it all day it's just noting that repeated exposure to the force adds up. So forces that can feel inconsequential in low volume can sometimes end up creating enough fatigue over time for it to become of some significance. Or perhaps not, depending on the specifics.

Are other declarative statements you make (like the convoluted explanations about the "axle") similarly just opinion?
When you replied "No" to my previous comment, what if that comment was merely my opinion? Are you trying to shut down my opinion?

Seriously now, there's a notable difference between the former comment ""would actually get surprisingly tiring..." and the following comment "can sometimes..."

 

[ICS]

Just as I thought, 42 hasn't learned to chop yet. There is so much conjecture in what gets said I don't know why anyone even tries to reason. One could speculate that most of these basic tools were invented by practitioners, not academics, improved upon over time according to their needs (or when they found a better handle). Yes you can apply the principles of science to try and explain the virtues of balance, torque and other such matters but for me, that doesn't get the wood cut, tree felled or a place on the podium if you were that way inclined. Get out there and learn how to use the things, that just might add some credibility to a few of the arguments being proffered. Cheers, ICS


Sent from my iPad using Tapatalk

 

[Carabnr]

@Square_peg
Cool pics, and TY for the replies.

 

[Steve Tall]

I'm not sure I follow...in a "7" balanced axe you won't experience any torque when the axle is at 0° to the horizontal (the center of gravity over the hand) despite the handle being at a skew to it. And perhaps I may have been misunderstanding your prior note--you're still talking about the CoG being moved forward with the edge/handle remaining in their original starting position in space, right? Sorry--juggling a lot of things right now so I read over it quickly.

Here's a better way to word my statement:

"Ironically, this "tiring" comment is about the case of having a center of gravity that's further in front of the handle (which can apply to poll-less axes when compared to axes with substantial polls)."

The increased torques resulted from having a CoG moved "forward" from where it was in the initial case, regardless of the distance to the bit. (The initial case had the CoG directly aligned with the axis of the straight handle, which can occur with a double bit axe, or a single bit axe with a substantial poll. A straight handle with a poll-less head would be more like the case with the increased torques.

 

[Steve Tall]

I believe that in the third table (comparison) 22 degrees should be a difference of 0.2 (11.3 - 11.1).

That's just round-off error:

11.251-11.126=0.125

 

[FortyTwoBlades]

Just as I thought, 42 hasn't learned to chop yet. There is so much conjecture in what gets said I don't know why anyone even tries to reason. One could speculate that most of these basic tools were invented by practitioners, not academics, improved upon over time according to their needs (or when they found a better handle). Yes you can apply the principles of science to try and explain the virtues of balance, torque and other such matters but for me, that doesn't get the wood cut, tree felled or a place on the podium if you were that way inclined. Get out there and learn how to use the things, that just might add some credibility to a few of the arguments being proffered. Cheers, ICS


Sent from my iPad using Tapatalk

What in the world is your basis for stating that I haven't learned to chop? As I told Old Axeman: attack my ideas--not me--or else you're all noise and no substance. The concepts I've presented do bear out in use. Try observing them for yourself and then tell me where they held true or fell flat. Academic and practitioner are not mutually exclusive terms and it's absurd to think that because I've gone to lengths to explain what are really very simple concepts that I somehow don't know how to swing an axe...

Here's a better way to word my statement:

"Ironically, this "tiring" comment is about the case of having a center of gravity that's further in front of the handle (which can apply to poll-less axes when compared to axes with substantial polls)."

The increased torques resulted from having a CoG moved "forward" from where it was in the initial case, regardless of the distance to the bit. (The initial case had the CoG directly aligned with the axis of the straight handle, which can occur with a double bit axe, or a single bit axe with a substantial poll. A straight handle with a poll-less head would be more like the case with the increased torques.

Again, that's dealing with cases where your axle's position has shifted. To use your method of example, the CoG should begin at 90° in all cases for comparative purposes. Consider the torque of the original axe when the CoG sits the same number of degrees to the rear. That is the difference between how you are looking at it and how I am looking at it. Because the axe will always inherently want to move in reference to the CoG it's the pivotal factor (literally and figuratively) in the use of all hand-manipulated tools.

 

[Steve Tall]

Formulas used in the spreadsheet:

Straight handle of length H (measured along center axis of handle to axe's center of gravity), at an angle α (where α=0 at horizontal).

Center of gravity can be moved from the center axis of handle by a distance D (at a right angle to center axis of handle).

Horizontal component of handle = H cosα

Horizontal component of distance the center of gravity is moved = D sinα

Total horizontal component of Center of Gravity location =
(H cosα + D sin&#945

Weight of axe = W

"Torque" = "moment" =
W (H cosα + D sin&#945

 

[Steve Tall]

Again, that's dealing with cases where your axle's position has shifted. To use your method of example, the CoG should begin at 0° in all cases for comparative purposes. Consider the torque of the original axe when the CoG sits the same number of degrees to the rear. That is the difference between how you are looking at it and how I am looking at it. Because the axe will always inherently want to move in reference to the CoG it's the pivotal factor (literally and figuratively) in the use of all hand-manipulated tools.

I think that's B.S. (clearly my opinion). Simpler is better in this case, and not just because it results in less convoluted explanations. When comparing two axes in the field, for example, the position of the handle is much easier to determine and continually reference (since it's right in front of your face), instead of some invisible or imaginary line.

And I think you're reading too much into the CoG's properties. An axe does not inherently want to move like that; instead, the axeman moves it where he wants to move it, and the CoG location influences the resulting torque that he/she feels in hand.

 

[Square_peg]

Just as I thought, 42 hasn't learned to chop yet. There is so much conjecture in what gets said I don't know why anyone even tries to reason. One could speculate that most of these basic tools were invented by practitioners, not academics, improved upon over time according to their needs (or when they found a better handle). Yes you can apply the principles of science to try and explain the virtues of balance, torque and other such matters but for me, that doesn't get the wood cut, tree felled or a place on the podium if you were that way inclined. Get out there and learn how to use the things, that just might add some credibility to a few of the arguments being proffered. Cheers, ICS

I think part of this is that he's trying to figure out through diagrams what an old axe man just feels in his elbows and wrists and shoulders when he uses the tool. The diagrams can be helpful but often they lead to conjecture that would disappear after the first few swings.

"One test result is worth one thousand expert opinions."
Wernher von Braun

 

[FortyTwoBlades]

I think that's B.S. (clearly my opinion). Simpler is better in this case, and not just because it results in less convoluted explanations. When comparing two axes in the field, for example, the position of the handle is much easier to determine and continually reference (since it's right in front of your face), instead of some invisible or imaginary line.

And I think you're reading too much into the CoG's properties. An axe does not inherently want to move like that; instead, the axeman moves it where he wants to move it, and the CoG location influences the resulting torque that he/she feels in hand.

And I think you're foolishly and willfully ignoring a simple and easily identified characteristic. The fact that it is an invisible line to the naked eye does not diminish its importance, and like countless such important-but-not-directly-visible things, it is still able to be observed; it has a tangible impact on the function of the tool. An axe does inherently want to move like that. If it behaved the way that you described then no axe would be inherently wobblier than another except for the distance of the edge from the handle, and this is demonstrably not the case. The CoG may influence the torque experienced, but my discussion regarding these behaviors has very little to do with fore/aft torque, but rather rotation around the distal axis. The rotational stability of the axe when forces are acting upon it. I am honestly surprised that you cannot see this. Please try to apply what I've discussed to a real physical axe and tell me if you are unable to reproduce what I've been talking about. I know you have a Calabria to try this with.

 

[FortyTwoBlades]

I think part of this is that he's trying to figure out through diagrams what an old axe man just feels in his elbows and wrists and shoulders when he uses the tool. The diagrams can be helpful but often they lead to conjecture that would disappear after the first few swings.

"One test result is worth one thousand expert opinions."
Wernher von Braun

I agree with the quote, and I sure hope that that's what he's trying to say. The problem is that the experienced axe user that has cultured their skills through intuition is that often they do not consciously understand or have the ability to explain precisely what is going on in those dynamics, and the brain has so many ways of altering aspects of the stroke etc. that it's easy to superficially think that some factors don't have an impact on the tool in use when they've actually subconsciously altered their stroke to compensate for it. This is something I've actually brought up in the scythe thread regarding the bit of lore that a snath must be made or adjusted exactly for its user to yield good results. While it's true that that's the ideal, and that such matters are of greater importance with scythes than with most tools, it is possible for the user to adapt their technique to the tool within a certain reasonable range and achieve good results in relative comfort. It's simply less harmonious than if the tool is adapted to the natural stroke of the user. It is this way, too, with axes. The user may adapt themselves to the tool and achieve good results, but is best-suited by optimizing the form of the tool to match the user's natural motion.

 

[Steve Tall]

Formulas used in the spreadsheet:

Straight handle of length H (measured along center axis of handle to axe's center of gravity), at an angle α (where α=0 at horizontal).

Center of gravity can be moved from the center axis of handle by a distance D (at a right angle to center axis of handle).

Horizontal component of handle = H cosα

Horizontal component of distance the center of gravity is moved = D sinα

Total horizontal component of Center of Gravity location =
(H cosα + D sin&#945

Weight of axe = W

"Torque" = "moment" =
W (H cosα + D sin&#945

In the spirit of "open source" if anyone wants to make an improved version, have at it. This was meant to be a simple example of what could be done with a different (yet more conventional) approach. Some simplifications could surely be eliminated to result in more accuracy, if desired.

 

[FortyTwoBlades]

The above only applies very very minimally to the matters that have been the core of the debate thus far. But if you want to have some fun sandboxing, here's a little interactive that lets you set a pivot on a simple block construct and you can see how it swings due to the influence of the CoG.

 

[idaho_crosscut]

well, this has gotten to be a long thread. Just wanted to post a picture of my hytest. not very much of a poll here!

 

[Steve Tall]

And I think you're foolishly and willfully ignoring a simple and easily identified characteristic. The fact that it is an invisible line to the naked eye does not diminish its importance...

Straw man argument(?)

An axe does inherently want to move like that...

Here's about how much an axe "inherently wants to move like that", according to conventional physics:

The simplified example with a 4-pound axe (with 36 inch handle) held vertically, with the center of gravity one inch in front of the vertical, results in only 0.33 foot-pounds more torque to hold it in this position, when compared with the other example with the CoG directly overhead. The extent that the axe "inherently wants to move" to reduce this 0.33 foot-pound torque is much less than the extent that the axe "wants to move" downward due to gravity (4 pounds in hand, compared to the equivalent of 4 ounces held level a foot away from the hand), and yet the axeman still holds up those 4 pounds, just like he/she will still hold back those relatively minor 0.33 foot-pounds.

... If it behaved the way that you described then no axe would be inherently wobblier than another except for the distance of the edge from the handle...

Big mistake you're making here, the calculations I did are for movement in 2 dimensions, as mentioned earlier (and presumably obvious). This was spurred on by your claims about "desire to tilt forward or backward", which happens in 2 dimensions. I showed a way that these affects could actually be quantified, to give a fuller understanding of what's going on. (I thought you'd be appreciative. ) "Wobble" and inherent "wobbliness" occur in 3 dimensions, with some other causes unrelated to these calculations.

...The CoG may influence the torque experienced, but my discussion regarding these behaviors has very little to do with fore/aft torque, but rather rotation around the distal axis. The rotational stability of the axe when forces are acting upon it...

Again, your discussion included some dubious-sounding (and changing) claims about "desire to tilt forward or backward", which is the reason I did these calculations, to provide an improved way to make those determinations. Again, I thought you would be appreciative.

... I am honestly surprised that you cannot see this. Please try to apply what I've discussed to a real physical axe and tell me if you are unable to reproduce what I've been talking about. I know you have a Calabria to try this with.

I'm honestly surprised that you are holding on so tightly to your theories and methods. Remember, I'm just addressing the 2-D aspects of the motion. With "real physical" axes, the forces or torques required to hold an axe straight out horizontally are clearly much greater than the forces or torques required to hold it overhead (with the center of gravity off the vertical by a couple inches), and yet the axeman is able to achieve both these "feats" (despite those "inherent desires" of the axe). This is in agreement with the calculation results. Yet, you keep insisting that the axe "inherently wants to" move back those couple inches to bring the center of gravity back to vertical, as if this were such a major force relative to all the other forces in play.

This is a major flaw in your theories, regardless of your attempts to minimize these issues.

 

[Steve Tall]

The above only applies very very minimally...

I strongly disagree. As I said earlier, I think it points out some major (but fixable) flaws in your theories. Mostly about reading too much into the concepts related to Center of Gravity, especially regarding motion in 2 dimensions.