A couple more diagrams on axe balance.

[FortyTwoBlades]

Sounds like the "guilt by association" fallacy. If this is a way of asserting that I am making a number of errors, then how about listing them specifically?

No, I'm just saying that Cook isn't a wholly accurate source. His inaccuracies have no bearing on yours.

 

[Steve Tall]

I was just making the connection out loud.

I think it was useful, thanks. I was just trying to avoid any "guilt by association" arguments.

 

[Woodcraft]

I remember when you first brought up the forearm aspects, and it was a bit of a revelation to me. Those influences make sense to me, along with other effects regarding the motions of the shoulder and elbow joints, which all combine to make the axe swing more complicated than my limited understanding. The rotation of the forearm is definitely happening in the demonstrations I suggested (with book, axe, and hatchet).

Well, the reality of any good horizontal ax swing is not an arm swing. It starts at the feet. The weight shifts to the back foot, then shifts to the front foot. Very gracefully this opens the hips. Or brings them from "sideways" to a more "facing" position of the object being struck. Then in turn the abs or mid section turns. And that turns the shoulders. All of that momentum if you will is transferred into the arms. While the axe is still close to the body the bottom hand is sort of "pulling and guiding". And the top hand the heel of the hand is "pushing and sliding" if you will. All of this done properly and "easily" results in a smooth and easy swing. Some people stand flat footed and arm swing I suppose. Pretty poor form.

 

[Steve Tall]

I've debunked Cook's 2nd diagram before so will do it only briefly here.

The axe would only pivot along the axle of the grip if one were to relaxe their grip and allow it. But that doesn't happen. Instead the grip is just a more comfortable interface between the arm and the haft. The actual rotation takes place in your forearm. Grab an axe and rotate it and you'll see this is so.

Slightly modified and it still applies:

The axe would only pivot along the "red line" if one were to relax their grip and allow it. But that doesn't happen.

 

[quinton]

I'm not sure what this means but here's another avenue of thought for you all.

If the real rotation of the axe takes place in your forearm, and I think I've demonstrated that it does, then the hand, the grip and the haft are working together to align the axe to THIS axis of rotation. Energy is spent in the wrist and hand to make this alignment. The more efficient this interface is the less energy is spent in the wrist and hand. Handle forms likely developed to create a more efficient interface. Whether that increases accuracy or just allows you to work longer I'm not sure - maybe it does both.

True.
The picture below was a total waste of my time, and a good stave. Well..maybe not a total waste as I learned something without making extensive calculations.

 

[Woodcraft]

I'm not sure what this means but here's another avenue of thought for you all.

If the real rotation of the axe takes place in your forearm, and I think I've demonstrated that it does, then the hand, the grip and the haft are working together to align the axe to THIS axis of rotation. Energy is spent in the wrist and hand to make this alignment. The more efficient this interface is the less energy is spent in the wrist and hand. Handle forms likely developed to create a more efficient interface. Whether that increases accuracy or just allows you to work longer I'm not sure - maybe it does both.

I'm not following you.? The whole body should be rotating. Unless you are arm swinging. Are we still talking horizontal swing?

I would imagine the curve in the bottom of the handle evolved to deal with extension, or the overextended bottom wrist. Nothing I have thought about untill now, but it would make sense.

 

[FortyTwoBlades]

Re: "That doesn't mean it's impossible to cause it to rotate around a different axis, but doing so is not its natural axis of rotation and so will induce torque that you have to fight in order to cause that rotation."

That effect, when present, is not very significant (relative to the forces being applied to the axe) and is easily overridden (as apparent in the demonstrations with the book and the axe).

It depends entirely on the axe and the location of the hands. It can range from not very significant to quite significant due to the relative ease/difficulty of applying those forces at different times. Are you arguing that there's no reason to tune a handle for a given head to reduce torque?

Re: "Now, as you yourself previously established, if you're rotating the axe around the handle when that handle does not align with the center of gravity, the head will be prone to torque on the handle. However, torque you apply to the handle (presuming no difference in handle shape at either point) will be identical and so it's fallacious to say that the upper hand will have any mechanical advantage over the lower hand when it comes to twisting the axe and causing wobble."

Not true. The upper hand will indeed have mechanical advantage over the lower hand, and it can cause wobble from off-center applications of force on the handle, as well as purely lateral applications of force that push the imbalanced head out of alignment.

If the handle were on a unified axis, lateral motions would simply cause the entire axe to tilt side to side (roll axis) while wobble occurs in the yaw axis. Applying twisting forces with the upper hand along the yaw axis will have no greater strength than the lower hand. If the handle runs out of line with the center of gravity, it's possible to fight the torque of the bit and cause the axe to rotate around the handle of the axis, but that's not what happens when your upper hand is sliding--instead, any pressure that's not put straight behind the handle will cause the axe to want to pivot around the natural axle (red line) as if it were a door and the red line were the hinge.

Re: "Take such an axe and stand the butt end on your palm and encircle the handle with your forefinger and thumb of the upper hand and wobble it side to side. You'll see the path the handle wishes to trace is conical rather than vertical."

Again, the motions of an unconstrained handle do not translate into a significant effect on a gripped handle.

They do, though, as it has to do with behavior during the stroke when the upper hand is freely sliding.

 

[Woodcraft]

Well, the reality of any good horizontal ax swing is not an arm swing. It starts at the feet. The weight shifts to the back foot, then shifts to the front foot. Very gracefully this opens the hips. Or brings them from "sideways" to a more "facing" position of the object being struck. Then in turn the abs or mid section turns. And that turns the shoulders. All of that momentum if you will is transferred into the arms. While the axe is still close to the body the bottom hand is sort of "pulling and guiding". And the top hand the heel of the hand is "pushing and sliding" if you will. All of this done properly and "easily" results in a smooth and easy swing. Some people stand flat footed and arm swing I suppose. Pretty poor form.

At 2:22 you can see exactly what I am talking about.

 

[FortyTwoBlades]

Here's a fairly simple question. Does anyone think that the axe with the offset neck is going to inherently want to twist in the hands during a horizontal swing? If so, explain your reasoning.

 

[Steve Tall]

It depends entirely on the axe and the location of the hands. It can range from not very significant to quite significant due to the relative ease/difficulty of applying those forces at different times.

Then how about showing some real-life examples where the effect is "quite significant" (in the context of what I've been disputing)? I gave some real-life examples (book, axe, hatchet) that show that the claimed effect is not very significant.

Are you arguing that there's no reason to tune a handle for a given head to reduce torque?

That's not what I said. I am disputing the unwarranted claims that you made about the red line.

If the handle were on a unified axis, lateral motions would simply cause the entire axe to tilt side to side (roll axis) while wobble occurs in the yaw axis. Applying twisting forces with the upper hand along the yaw axis will have no greater strength than the lower hand. If the handle runs out of line with the center of gravity, it's possible to fight the torque of the bit and cause the axe to rotate around the handle of the axis, but that's not what happens when your upper hand is sliding--instead, any pressure that's not put straight behind the handle will cause the axe to want to pivot around the natural axle (red line) as if it were a door and the red line were the hinge.

Actually, a lateral motion could do more than "simply cause the entire axe to tilt side to side." You are ignoring the fact that the upper hand can apply a lateral force to the handle, but with it applied off-center to the axis of the handle, resulting in a twist to the head. (This should be easily observable in the flattish-handled Italian axes.) So what I wrote still stands.

They do, though, as it has to do with behavior during the stroke when the upper hand is freely sliding.

I was expecting some push-back, but the "yes it does"/"no it doesn't" parts are probably getting tedious for all of us. I'm trying to be helpful, and you indicated that you were open to "improvements" to your theories, but it seems like you don't make any concessions without a lot of argument (like with the handle torque, earlier in the thread).

To advance your arguments further, I suggest using real-life examples (like I tried to do), instead of making unverifiable claims.

 

[Square_peg]

I think the offset neck will make the axe more stable and more accurate. You call it a unified axis and I'm fine with that. In the past I've called the two axis' the axis of rotation and the axis of control, one thru the center of gravity and one thru the forearm, grip and haft. In any case, when they coincide within the haft I believe you will have a more comfortable and accurate axe.

 

[Goose 7279]

More pictures. The piece of tape on the head marks where the drop line passes through. As previously noted, the center of gravity is out in empty space, though I could probably rig up something with fencing wire to demonstrate that if deemed necessary. The axe will balance horizontally on any two points on a line passing through the center of gravity.

One end on a grade stake, the other on a finger.

Two grade stakes so I can actually take shots from multiple angles.

With the lower grade stake moved up on the handle. Still balances fine because the main length of the handle lies on that same axis.

Doesnt this show that it is bit heavy? If not why wouldnt the other stake be where the handle meets the head not on the bit?

 

[Steve Tall]

...On the red line. That's where all the rotation takes place when the upper hand is sliding, and is the axis from which bit depth as pertains to wobble should be measured from. If you have a bit that measures 8" to the eye but only 4" to the axle, the amount of bit travel that occurs from any twisting of the axe will be the same as on a double bitted axe with 4" deep bits.

These claims are easily disproved with the example I gave, holding an unbalanced axe parallel with a tabletop. Easiest to demonstrate with a straight handle. Have the sliding hand cause twisting of the head, while the handle axis remains parallel to the tabletop. There, that was easy. The rotation took place along the axis of the straight handle, not the red line, and the first claim (in bold) has now been refuted.

The second claim (in bold) can also be refuted with a similar demonstration. Twist the single and double bit axes (not at the same time, obviously) while keeping the handle axis parallel to the table top. Again, easily done. The edge on the 4" deep double bit will travel less than the edge on the 8" single bit.

 

[Goose 7279]

I think the offset neck will make the axe more stable and more accurate. You call it a unified axis and I'm fine with that. In the past I've called the two axis' the axis of rotation and the axis of control, one thru the center of gravity and one thru the forearm, grip and haft. In any case, when they coincide within the haft I believe you will have a more comfortable and accurate axe.

Yea i agree with this statement. I would think the line in my mind would follow the end to end of the handle. Not a straight line from the handle end through middle of the bit? I dont know if what im saying makes sense. Someone who can explain it better will be able to feel me in.

 

[FortyTwoBlades]

Doesnt this show that it is bit heavy? If not why wouldnt the other stake be where the handle meets the head not on the bit?

Huh? The location of the eye has very little to do with the balance of the overall axe other than where the handle is attaching. There is more mass in front of the eye than behind it, obviously, but the bit side of the axe is not going to dive during horizontal strikes like it would have on the factory handle. The axe has been brought into horizontal balance by putting as much of the handle as possible in alignment with the center of gravity.

 

[FortyTwoBlades]

Then how about showing some real-life examples where the effect is "quite significant" (in the context of what I've been disputing)? I gave some real-life examples (book, axe, hatchet) that show that the claimed effect is not very significant.

During the stroke if you were using the upper hand to apply your counter-torque and then begin sliding your hand you'll get immediate wobble with a very limited timeframe before the axe lands to correct it. That's not trivial. And depending on how out of line that handle is it can end up being fatiguing in extended use, even when properly using the heel of the palm of the lower hand to counteract that force.

That's not what I said. I am disputing the unwarranted claims that you made about the red line.

I've gone to fairly significant lengths to demonstrate the interaction of the physical axe and the natural axle. You have a 700g Calabria, so try playing around with it. I can even draft up a handle pattern for it and email it to you as a printable PDF for you to try out and see the difference.

Actually, a lateral motion could do more than "simply cause the entire axe to tilt side to side." You are ignoring the fact that the upper hand can apply a lateral force to the handle, but with it applied off-center to the axis of the handle, resulting in a twist to the head. (This should be easily observable in the flattish-handled Italian axes.) So what I wrote still stands.

Except you're dealing with a very short lever arm in that case, which would then be countered almost instantly by the other end of the handle rotating into the palm with equal force. The lever arm in the case of an off-axis handle interacting with the natural axle is a good deal more influential. Think of it as a triangle being defined by the center of gravity and both hands. Take a triangle of wood and hold it between your forefinger and thumb, or a finger and a tabletop, then try applying a straight push into the remaining point. If you push straight and true, force is directed without issue, but even a small slip to the side causes it to spin out of control.

I was expecting some push-back, but the "yes it does"/"no it doesn't" parts are probably getting tedious for all of us. I'm trying to be helpful, and you indicated that you were open to "improvements" to your theories, but it seems like you don't make any concessions without a lot of argument (like with the handle torque, earlier in the thread).

That's...kind of how debate works, though? If your assertions were immediately recognizable as correct then I'd take them as such. If they don't make sense or I feel they're flawed, I'm going to attempt to refute them.

To advance your arguments further, I suggest using real-life examples (like I tried to do), instead of making unverifiable claims.

They're verifiable, though, and I've been doing everything I can in order to show them in action. You do have examples of at least one axe that falls into this category, so I'd suggest playing around with it some and a lot of what I'm talking about should practically leap out at you.

 

[Goose 7279]

Huh? The location of the eye has very little to do with the balance of the overall axe other than where the handle is attaching. There is more mass in front of the eye than behind it, obviously, but the bit side of the axe is not going to dive during horizontal strikes like it would have on the factory handle. The axe has been brought into horizontal balance by putting as much of the handle as possible in alignment with the center of gravity.

I wasnt throwing off on the axe or saying that it would dive when using 2 hands just saying that it would still be bit heavy. I believe you definately improved the axis of control of the axe.

But i would think that a perfectly balanced ax you could balance at a single point or iin your pictures a stake and the bit would stay horizontal. As i said im no expert or understood most of the stuff in this thread. I got alot of respect for everyone in this thread and have actually purchased from baronyx . So im not wishing to ruffle any feathers. Im just trying to understand.

 

[FortyTwoBlades]

I wasnt throwing off on the axe or saying that it would dive when using 2 hands just saying that it would still be bit heavy. I believe you definately improved the axis of control of the axe.

But i would think that a perfectly balanced ax you could balance at a single point or iin your pictures a stake and the bit would stay horizontal. As i said im no expert or understood most of the stuff in this thread. I got alot of respect for everyone in this thread and have actually purchased from baronyx . So im not wishing to ruffle any feathers. Im just trying to understand.

The center of gravity is out in the empty space between the offset of the neck and the bit so that's not possible to do. If the straight region of the handle kept on going instead of curving into the offset then it would pass through the center of gravity, and then I could do that, though.

 

[Goose 7279]

The center of gravity is out in the empty space between the offset of the neck and the bit so that's not possible to do. If the straight region of the handle kept on going instead of curving into the offset then it would pass through the center of gravity, and then I could do that, though.

So you could balance it at on single point and the bit would stay horizontal with the straight haft? Right?

 

[FortyTwoBlades]

These claims are easily disproved with the example I gave, holding an unbalanced axe parallel with a tabletop. Easiest to demonstrate with a straight handle. Have the sliding hand cause twisting of the head, while the handle axis remains parallel to the tabletop. There, that was easy. The rotation took place along the axis of the straight handle, not the red line, and the first claim (in bold) has now been refuted.

The second claim (in bold) can also be refuted with a similar demonstration. Twist the single and double bit axes (not at the same time, obviously) while keeping the handle axis parallel to the table top. Again, easily done. The edge on the 4" deep double bit will travel less than the edge on the 8" single bit.

Again, being able to move an axe around an axis that's not running through the center of gravity proves nothing--all you've done is overcome the forces that were resisting you doing such a thing...