Tom Clark - wood splitter and innovator

[rjdankert]

. . .here's a few unhafted heads I have floating around at the moment. . .

I just did the same "test" with seven heads and got pretty much the same results. Seems like the ones I used balanced a little more toward the bit than the ones pictured, but none past the eye.


Bob

 

[Woodcraft]

I just did the same "test" with seven heads and got pretty much the same results. Seems like the ones I used balanced a little more toward the bit than the ones pictured, but none past the eye.


Bob

I think to get a result that is close to accurate you would have to fill the axehead with some Styrofoam mark the centerline from bit to poll and use a small diameter rod both coming in and going out the centerline the same distance from the bit. I think the results will surprise you. Maby not. I will do it later this week on a couple of craftsman heads.

 

[Square_peg]

Just looking at its thin bit and the fact that most American axe heads balance about 1/4" inside the front of the eye....

For the sake of this thread I just tested this on 5 axes. I rolled a dowel under the axe head until I located the tipping point. Here's where I found the balance points:

5 lb. Plumb rafting axe - 1/4" inside the front of the eye
4 lb. Stiletto Michigan with eye ridges (likely a True Temper) - 1/4" inside the front of the eye
3.5 lb Craftsman single oval Michigan - 1/4" inside the front of the eye
5 lb Warren Old Faithful - 3/16" inside the front of the eye
5 lb Walters rafting axe (the one with the massive eye walls) - right at the front of the eye

I was surprised that the balance on the Plumb wasn't further back.

 

[Woodcraft]

For the sake of this thread I just tested this on 5 axes. I rolled a dowel under the axe head until I located the tipping point. Here's where I found the balance points:

5 lb. Plumb rafting axe - 1/4" inside the front of the eye
4 lb. Stiletto Michigan with eye ridges (likely a True Temper) - 1/4" inside the front of the eye
3.5 lb Craftsman single oval Michigan - 1/4" inside the front of the eye
5 lb Warren Old Faithful - 3/16" inside the front of the eye
5 lb Walters rafting axe (the one with the massive eye walls) - right at the front of the eye

I was surprised that the balance on the Plumb wasn't further back.

I am not suprised with the Michigan pattern. Didnt happen to take any pictures did you?

 

[FortyTwoBlades]

I pointed to the patent to qualify "it" as a condition for taking the bet. Since you have seen the patent since the above quote, do you still "bet that it shifted the center of gravity, if not behind the eye, certainly to the very rear of it".


Below shows the pin (#8) and the shaded area where the CoG is intended:

Description from the patent:

"1. A splitting axe having a head unbalanced with respect to a handle of said axe, said head having an eye, said handle having a portion received within said eye, said head having an anterior portion extending from one end of said eye and terminating in a cutting edge at one end of said head and a posterior portion extending from the opposite end of said eye to the end of said head remote from said cutting edge, the mass of said head having a weight distribution for providing an unbalanced disposition of said head on said handle whereby the center of gravity of said head is located within said eye and upon an axis passing through said center of gravity and parallel to the longitudinal center line of said eye, said axis being located anteriorly of said longitudinal center line, said center of gravity axis accordingly lying between said longitudinal center line and the anterior limit of said eye, said posterior portion being weighted and oriented posteriorly relative to said longitudinal center line."



Bob

I think the marked locations on the patent document (as is often the case with these things) are not perfectly indicative of the genuine locations of the center of gravity of the finished product. I would say that the center of gravity on the one that Worthpoint had photos of probably balanced juuuust in front of the markings on the head. Patent documents are not meant to be engineering blueprints, but rather explanations that illustrate the innovation being patented. You can see even in the document diagrams that the distance between the CoG and the pin is significantly different between the two drawings.

That being said, looking through the "legalese" of the document it does look as though he believed that the CoG had to sit forward of the centerline of the handle, which I don't think is actually necessary because the leverage is occurring with a forced fulcrum rather than the center of gravity--the location of natural pivot--playing the same influential role as it does when the tool is swung or rotated in space. Once the edge hits, the contact point with the wood is necessarily the fulcrum in the lever's rotation, and so a deep bit and/or poll would lengthen that lever. I'd need to do some more thinking on that to work out the influence the CoG would have at and after impact, but that's what I'm thinkin' right now at least.

 

[Woodcraft]

I just did the same "test" with seven heads and got pretty much the same results. Seems like the ones I used balanced a little more toward the bit than the ones pictured, but none past the eye.


Bob

As I said earlier I will do this test properly (with foam and rod and pictures. Perhaps a "balance thread for plunbline and balance photos?)later on in the week. But I just did the "dowl" test for myself. 3.5lb unmarked Michigan the absolute inside.The sears boys axe, an unmarked hatchet and 3.5 dayton all had near as makes no difference the exact same balance point. As far as testing this way is concerned. 1/3rd of the way in from bit to poll. That is .666666667 on a two inch eye hole. On a related note, between 1/3rd of the way in to center is where the American axes I hung a plumbline on had the plumbline fall.

 

[rjdankert]

As I said earlier I will do this test properly (with foam and rod and pictures. . .

Not sure why you replied to my post (#61) twice.

If you want to contribute results from a more precise test, then I say go for it! :thumbup:


Bob

 

[Woodcraft]

Not sure why you replied to my post (#61) twice.




Bob

Two and a half hours later I grabbed a couple of free heads and It seemed to merit a separate response as opposed to a belated edit. Did I miss an internet etiquette class? Jk.

 

[rjdankert]

. . . Patent documents are not meant to be engineering blueprints, but rather explanations that illustrate the innovation being patented. . .

Absolutley. Did someone say something different? My reason for adding the shading on the drawing was only an attempt to create a visual interpation of the language. That is why I put the two together and changed the pertinent text to red.

If someone shows that I have the boundries wrong, I will mark that post as an error and put a corrected version in a new post.

. . .That being said, looking through the "legalese" of the document it does look as though he believed that the CoG had to sit forward of the centerline of the handle, which I don't think is actually necessary because the leverage is occurring with a forced fulcrum rather than the center of gravity--the location of natural pivot--playing the same influential role as it does when the tool is swung or rotated in space. Once the edge hits, the contact point with the wood is necessarily the fulcrum in the lever's rotation, and so a deep bit and/or poll would lengthen that lever. I'd need to do some more thinking on that to work out the influence the CoG would have at and after impact, but that's what I'm thinkin' right now at least.

So, what you are actually saying is that you are not a fan Tom's concept? Myself, I am keeping an open mind until evidence emerges to confirm or deny if the "Buster" splits wood easier.


Bob

 

[rjdankert]

Two and a half hours later I grabbed a couple of free heads and It seemed to merit a separate response as opposed to a belated edit. Did I miss an internet etiquette class? Jk.

Jk, I didn't understand that the second was a continuation of the first.

Sorry, I don't know anything about internet etiquette classes.



Bob

 

[FortyTwoBlades]

Absolutley. Did someone say something different? My reason for adding the shading on the drawing was only an attempt to create a visual interpation of the language. That is why I put the two together and changed the pertinent text to red.

If someone shows that I have the boundries wrong, I will mark that post as an error and put a corrected version in a new post.

Nah--you have them right! I just find the patent information interesting in what it's asserting and that using it for the purpose of identifying the location of the center of gravity on the actual manufactured heads is potentially problematic, so the text is more valuable towards that end than what the diagram strictly shows. Just expressing how patents can be misleading regarding the final product.

So, what you are actually saying is that you are not a fan Tom's concept? Myself, I am keeping an open mind until evidence emerges to confirm or deny if the "Buster" splits wood easier.


Bob

To the contrary I like his concept very much! I'm just not sure of how sound his reasoning is about needing the CoG to sit forward of the centerline of the handle for it to work right. I presently think that's a false requirement, and not strictly necessary, but would need to do more figuring before making a firm assertion. :thumbup:

 

[300Six]

Absolutley. Did someone say something different? My reason for adding the shading on the drawing was only an attempt to create a visual interpretation of the language. That is why I put the two together and changed the pertinent text to red.

If someone shows that I have the boundries wrong, I will mark that post as an error and put a corrected version in a new post.

So, what you are actually saying is that you are not a fan Tom's concept? Myself, I am keeping an open mind until evidence emerges to confirm or deny if the "Buster" splits wood easier.

Bob

Tom's patented critter (especially with him 'guiding' the end of it) has outright proven itself to work well whereas 42Blade's long-winded academic analysis of why, hasn't. Off balance - hefty poll - swing at an angle, or twist upon impact, must have an effect, and from my limited experience at watching folks that know how to do this; shape, weight and profile of the axe itself is almost immaterial except that none of those axemen ever sought out 'heavies' when they were doing it.

 

[Steve Tall]

...I'm just not sure of how sound his reasoning is about needing the CoG to sit forward of the centerline of the handle for it to work right.

Neither am I.
Perhaps it was part of the patent lawyer's way of distinguishing Tom's design from earlier patents, like this one:

 

[rjdankert]

Neither am I.
Perhaps it was part of the patent lawyer's way of distinguishing Tom's design from earlier patents, like this one:
. . .[/IMG]

I don't want to discuss the particular patent shown, but I also wonder if patent infringement could have played a role. Another speculation is that he could have made prototypes with the CoG back further and did not find them to his liking.


Bob

 

[FortyTwoBlades]

Tom's patented critter (especially with him 'guiding' the end of it) has outright proven itself to work well whereas 42Blade's long-winded academic analysis of why, hasn't. Off balance - hefty poll - swing at an angle, or twist upon impact, must have an effect, and from my limited experience at watching folks that know how to do this; shape, weight and profile of the axe itself is almost immaterial except that none of those axemen ever sought out 'heavies' when they were doing it.

A condensed version just for you is that having more mass further from the edge at the time of impact is gonna' help with doing the busting because it's a longer lever arm for that mass.

 

[Square_peg]

He may have found that having the CoG too near the poll caused the axe to turn before it had adequate penetration. Just a guess.

 

[FortyTwoBlades]

He may have found that having the CoG too near the poll caused the axe to turn before it had adequate penetration. Just a guess.

Quite possible. Good thinkin'. I wish there were an easy way to test that line of thought and find out.

 

[FortyTwoBlades]

Interesting. Is it just me or does this look VERY "Buster axe-y"? Certainly Chinese or Indian production, but might be fun to take for a spin. Sold by a UK company, and called their "Abbey Pro Silverline Log Splitting Maul Hardwood 6lb"

 

[rjdankert]

Interesting. Is it just me or does this look VERY "Buster axe-y"? . . .

Where is the CoG located?


Bob

 

[FortyTwoBlades]

I don't have any idea beyond a guess...I don't own one. Just found it right now.