tomahawk from cpm3v?

[tatalley10]

Cpm-3v is so hard even a solid heat treat all over would make it so hard the handle would be the weakest link.

 

[Spey]

I dunno, the cool factor, having a hawk that I could beat to death forever and not worry about sharpening but every so often. I have a pipe hawk I just think against hardwoods it needs sharpening more than I like too...lol

That's cool. I'm mostly going against Pine, Cottonwood & W.Red Cedar. Find the edge holds up pretty well for what I'm using my hawks on. I have found that dropping the angle down, the edge does much better.

Here's a little competitive of 3V to Forged carbon steel:
http://www.woodcentral.com/woodwork...mparing-cpm-3v-with-forged-high-carbon-steel/

From what I've read forge welding 3V can kinda ruin the good properties. San Mai construction with a 3V section inserted would also possibly ruin some of the good 3V characteristics. Appears you need to do the hot-work so the 3V would not see oxygen during the process. A lot of the micro-grain structure of the CPM process is what can get lost.

 

[tatalley10]

Yeah I figured it would end up needing to be water jetted in one plane and cnc to profile and make the handle hole...

 

[Spey]

Yeah I figured it would end up needing to be water jetted in one plane and cnc to profile and make the handle hole...

Hmmm ... I didn't think of that, assuming they didn't make 3V thick enough to be able to make a eye big enough to accept a haft without some amount of forging :-/

If on the other hand, you're interested in "tacticool" tomahawk (non-traditional) check out Dan Keffler. Dan knows his way around choppers, both there use/performance and making of such. He did a breaching style 3V tomakawk along the lines of a Winkler about 4-5 years ago (flat stock one-piece with overlay handle scales).

In general though, I would "think" optimal hardness ranges for 3V to be higher than optimal for what most people would want/need in a tool designed for chopping. Otherwise I think we would have seen more 3V choppers in competition events already. I could very well be wrong, and may be the next in thing. Hope something here is of use to you.

Regards,

 

[idaho]

Good to know that 3V is magical, indestructible steel We should build tanks armour from it, or maybe armour piercing bullets?

3V might be great for knives, but hawks are a different game.
if you use hawk/axe hard, you WILL damage/destroy edge/edge grind.
And when it happens - it is better to have hawk a bit on the soft side.

 

[tatalley10]

So your saying it's to tough?

 

[Spey]

So your saying it's to tough?

No, "I think" in general folks misuse/misunderstand the term "tough" as it relates to things. In this case focus will be on tough as it relates to bladed tools (from my perspective).


In this case let's consider what we want tough to mean as it relates to improved performance over the lifecycle.


A positive performance characteristic of CPM3V is that the edge can be ground thinner while still retaining equal of even possibly superior toughness to other steels, say for example 1095. CPM3V can be heat treated to higher optimal RC of say 60rc vs 56rc for 1095 (optimal being related to the specifics of the individual steel, each steel having an optimal range of RC). The net result is a thinner (slicer) blade of equal or higher hardness.
To summarize: the positive performance characteristic of 3V over say 1095 is that it has greater toughness at higher hardness across thinner sections. Is our goal in designing a tomahawk to make a thinner blade, and or one with fine grained micro-structure (characteristic related to CPM technology more specifically PM technology if you remove the Crucible proprietary name from the actual manufacturing designation). I personally think not. Example: I want a tomahawk to be a good wood-splitter, to do this it needs to have wedging characteristic performance (described it greater detail below). Now maybe if someone says they want a tomahawk to be a good slicer (say maybe a can-opener like for breaching thin sheet metal then perhaps there may be positive characteristics worth exploring here and we move on to other "design parameters" in discussion of optimal steel selection for specific design purpose of the tool in question).


Now let's consider "toughness" as it relates to "strength" (specifically with consideration for strength against lateral stress or in this example bending). The most value (increase in strength) comes from increase in thickness (resistance to bending is cubically proportional to thickness). As example: a 2x increase in thickness from 1/8" to 1/4" yields an increase in stiffness of 8x (8-times the force is required to yield an equal amount of lateral (sideways) amount of flex. Reducing thickness unfortunately has less proportional overall benefit (I forget the factor, other than to say it's significantly less that a cubic ratio. So does our design goal include wanting a thinner tool with equal to greater strength? I think we already said no (exception may be as referenced above that perhaps we want slicer performance enhancement and are willing to accept decreases in performance on other areas to achieve this goal). Again, not a worthwhile sacrifice in my mind for a tomahawk (for my use perspectives and design goals).

With regard to "design" based on performance use:
I believe first you must consider geometry. How does the geometry of the blade work towards the purpose. If you want slicey, thin is in (you want thin geometry). Thin however, does not split very well. If you want to be able to split or wedge you want additional thickness. Consider when chopping, the first cut penetration is good. the second cut (opposite side of the V) you want to have penetration and wedging effect to push the wood/media sideways slightly as a self removal effect created by the downward force of the cut. Wedging comes from the thickness geometry. A thin blade geometry will penetrate ok (so long as it can resist deformation to the edge) but will get stuck in wood because of surface contact on the sides of the blade from poor wedging effect).


In general, as thickness increases I would say the positive characteristics of CPM3V diminish (remember that cubic 8x relationship that adding material thickness achieves).


I have two knives, both in CPM3V, that are both great examples of being overly thick to really see a significant performance increase. I bought these with assumption "3V is tough" therefore better. At some point it is my plan to significantly reduce the thickness on both in attempt to net a true performance cutting value. At this point after many comparision sessions with numerous other knife steels and geometries those knives don't see much light of day. When they do, like a couple days ago I brought them both out to retest against a number of other knives (wife gave me permission to harvest some of our standing lilac hardwood a few months back and I saved sections for knife testing purposes) it only took a minute or so with each to get that same sinking feeling "yes, I still need to get these two on the grinder and thin them out ..." to see to potential performance value of CPM3V.


Where "I think" CPM3V may have a future in tomahawks relates to sheet-stock-removal construction, and hawks designed as breaching type tools where slicing and penetration are the primary design goals. AND, were a user is ok with spending a lot of cash versus having mentalitiy that a breaching tools life cycle cost means that replacing a tool after a few uses becomes more cost effective than spending a lot up front. So, like the hawks I previously mentioned like that Dan Keffler similar to what most I think would reconginse today as a Winkler (No disrespect meant twoards either, but a small market share and very expensive value). At least this is my opinion as of today based on my experiences.


So in close, I will say geometry is so much more important than the selection of the steel. Understanding how and what various terms like "toughness" (charaterisitcs of performance goals) mean to the performance and how that relates to the geometry should be considered before just discussiong something like toughness. This approach should be followed all the way through to the heat treating and tempering process (because both these processes SIGNIFICANTLY affect the overall performance of the steel with regard to being able to support the design geometry).


Hope some of this makes sence, sorry for the length. Rehashing things in my mind helps to reinforce what I "think" I have learned and as always it seems "the more I learn, the less I know" (but, the overall understanding continually increases ;-)


Regards,
Christopher

 

[martinsanders]

Looking for tomahawk head made from cpm3v? Not a skinny one waterjeted from a solid plate and then sharpened and given handles.... I mean one that looks like a pipe hawk from coldsteel!!! A friction fit head... anyone seen one of these?

I don't know how much it would cost but I know a guy that does forge CPM steels and in fact made an awesome shovel from forging everything from s35vn to s125v. He even makes Damascus from it and I know he could make the tomahawk for you. Do me a favor and tell him Martin sent you. His name is Seth and you can find him here: seth at cosmoknives dot com
This is your guy. If he can make a shovel from I think 5(several I know) different CPM steels then he can make a tomahawk no problem.

 

[tatalley10]

I don't know how much it would cost but I know a guy that does forge CPM steels and in fact made an awesome shovel from forging everything from s35vn to s125v. He even makes Damascus from it and I know he could make the tomahawk for you. Do me a favor and tell him Martin sent you. His name is Seth and you can find him here: seth at cosmoknives dot com
This is your guy. If he can make a shovel from I think 5(several I know) different CPM steels then he can make a tomahawk no problem.

Hrmnn ..... I must check this out

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[martinsanders]

Her is a quote and the highEst quality stainless he is talking about is CPM steels. There are pictures below.

"The blade and ferrule was constructed out of five types of the highest quality stainless steels, forged and folded over a core of powdered tool steel. The result of this process was a single billet of metal consisting of over 200 layers. Having not made a shovel blade before, Seth drew on his considerable metal smith experience to find the combination of inert hardening and tempering that would produce a shovel blade that was both tough enough to endure repetitive striking against rock and which had high edge retention (capacity to remain sharp). After mastering the blade we moved onto designing the handle, shaft and fittings. For the shaft, we chose a wood, Cocobolo, known for its strength and weather resistance. Cocobolo has been used for centuries in knife and gun handle construction. The shaft was press fit, epoxied and pinned with a mosaic pin into the ferrule. The D-handle was constructed with a white oak core and reinforced with stainless steel. A mortis and tenon and stainless steel bolt fastened it to the shaft. The final touch was to wrap the D handle in multiple layers of carbon fibre. The last stage of the shovel construction was the grip which we formed out of stacked leather with a half inch square stainless tang and bolster.
Two hundred and fifty thousand trees later, the shovel still looks brand new and is valued at over $6000. Most standard shovels would struggle to last a single season of planting and certainly would not be considered a valuable piece of art. This shovel will last forever."
- See more at: http://www.silviculturemagazine.com...ate-tree-planting-shovel#sthash.gNccYVjx.dpuf

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