Cast-in-place aluminum knife handles

[RX-79G]

I've always wanted a Gerber ArmorHide A475 (not my pic)

But I also rarely see a Mora with broken tang despite the plastic handles. (again not my pic)

Indeed, one must wonder what great efforts it took to break the CS kukri-machete presented. I rarely see broken hidden-tang Bucks or even Kabars despite their enormous prevalence (the odd Kabar here or there vs. the millions about), broken SRKs or Randalls, etc. much less broken Bussekin. What i present to you is that whatever force is required to bend/break that steel tang is MORE than enough to bend/break the aluminum handle trying to support it unless that section of handle is ~2X thicker than the piece of steel being bent. If the fracture in the tang is due to impact-shock at an inclusion in the steel, again the aluminum doesn't help. While i have no doubt that the cast-in-place design will sell (those Gerbers sure did) I am not convinced it will lend any noticeable superiority in handle strength over a more comfortable material like plastic/micarta/wood where the tang provides the necessary strength, not the handle around it.

The typical knife handle is going to something like a 1" x 3/4" oval. If I gave you a 1x3/4" bar of aluminum, do you think you could break it? How about if the aluminum bar had a steel core running through it?

Tangs can and do break. Plenty of CS tangs, thinner full tangs, stick tangs in wood. They just need the opportunity to bend far enough at their weakest point closest to the guard.

I posted a pic of a Mora earlier. The tangs don't break generally because the handle fails completely, first. And being thin stick tangs, they are more able to bend under shock than a full tang, which will simply crack. The typical Mora tang is only .78" thick.

Personally (and a little off topic), I feel the best possible flat stock knife design would be one where a relatively large tang was wrapped - under tension - with linen and resin, then ground to shape. No holes or pins, plenty of lateral support, plenty of steel, no big stress risers, no complaints about hot or cold. A similar process is used to make light, high pressure air tanks. But that is much more labor intensive than casting aluminum - which works very well while being nearly indestructible.

Otherwise, one piece hollow handle knives like CRK and Robson's completely eliminate tang weekness, as do other drop forged or billet machined designs where the tang is thicker than the base of the blade.

 

[POCEH KOCEB]

POCEH KOCEB, I can see your posts when people quote you, but not otherwise. I set you on "ignore" after our last encounter. So please don't expect me to address your comments.

The thing is - you most likely cannot address my comments and I wasn't writing to you anyway, after you determine clearly the purpose of this thread, your opinions are simply useless to me because I don't think they are based on personal experience, something that I find important when I talk with somebody. This is what I did, communicating with someone on the subject of this thread, not trying to get your attention.
Hope someone quote this so you can see it, I wouldn't lose sleep if you don't...

 

[chiral.grolim]

Again, how much effort did it take to break that CS Kukri? From the image, it looks like it was bent back and forth multiple times - NOT easy to do by hand. BUT if there was an inclusion in the steel, it could have been fractured loose without any measurable bending, i.e. even a steel handle around it wouldn't have helped.
How about the Mora plastic handle cracking? The shorter tangs require a lot of strength but can be leveraged out of the plastic handle when it fails... try that with a longer tang (any of the lower 3 in the x-ray image) and the outcome is not so certain, it takes much more force to accomplish because the handle relies more on the strength of the tang. The tang of even a Mora is that strong, and I've never seen one crack out of a wood-handle unless the handle was being smashed with a hammer.

It is NOT easy to bend/crack a good tang despite very weak handle materials that provide excellent insulation against temperature and impact. Tangs can and do break regardless of the handle material, regardless of the presence/absence of pin-holes, because multiple factors are at play. Tang stock-thickness/width is primary, that's what Busses rely on (and good steel) - as you noted, they aren't easy to break. In the case of a Mora, like Busse their steel supplies the strength, not the handle material. And while a thinner mora will bend quite a bit before it cracks, it will start bending under MUCH less stress and probably take a permanent bend before the thicker busse even begins to bend elastically much less crack.

Most blades of any tang do not "simply crack" unless there is an inclusion (like the kitchen knife on the first page which fractured without any evidence of deformation of the stiff handle scales and nowhere near the first pin-hole). If the tang is 1/4" thick, and the handle supports each side with only 1/4" of aluminum (assuming the 3/4" handle you suggested), then the force required to bend that tang is more than enough to bend the aluminum on either side which requires 2X that thickness to be as strong as the steel it is supporting. If the tang is only 5/32" thick with 9.5/16" aluminum on either side, each side is as resistant to bending as the tang itself, but tang and aluminum-siding are still ~3x weaker than a 1/4" tang and not much lighter, so what was the point? A handle that can handle a lot of hammer-whacks and be lighter than steel?

Aluminum is strong and tough and light... but it is not as strong as steel and is not comfortable to hold. Why would anyone choose aluminum over a more comfortable material in a handle? The only reason must be that the tang is too weak to allow for a gentler material. If so, i (like others here) think that the problem lies first with the tang - make it stronger to handle the abuse to the blade, else make the blade weaker for more specific tasks. I would love to own one of those Gerbers but have no illusions about handle-comfort vs a plastic Mora handle with a longer tang that seems to provide sufficient strength for most applications. *shrug*

 

[chiral.grolim]

A better picture of that kukri break: http://www.bladeforums.com/forums/showthread.php/668281-broken-when-chopping!!

The steel was already fractured and rusting prior to the impacts which propagated that fracture to failure, nothing that a cast aluminum handle could have prevented (except by being too uncomfortable for the wielder to use).

 

[POCEH KOCEB]

Again, how much effort did it take to break that CS Kukri? From the image, it looks like it was bent back and forth multiple times - NOT easy to do by hand. BUT if there was an inclusion in the steel, it could have been fractured loose without any measurable bending, i.e. even a steel handle around it wouldn't have helped...

I know for a fact that some guys that replaced CS's handle with wooden-one had problems with vibrations when the Kukri was used, the handle wouldn't stay intact, actually if I remember right, in some forums they specifically warn new guys not to remove the pin in this particular model in order to prevent breakage of the handle.

The case with this particular CS Kukri is described here, in BF: http://www.bladeforums.com/forums/showthread.php/668281-broken-when-chopping!!/page2
Look at posts 6 (OP) and 7, here is a better picture from the same thread courtesy of scrumpy jack:

I believe you are correct - even surrounded by aluminum, cast or not, if you put enough pressure (hit it) on it, the tang will fail regardless of the softer metal surrounding it.
--------------------------------------
I see you beat me to this in a matter of seconds, sorry for the duplicate info...

 

[craytab]

Great minds think alike!

I don't generally agree with Chiral, especially on the Bravo 1 handle, but in this instance he has explained the problem with a cast aluminum handle perfect. Oh wait, was that parroting? Oh well.....

 

[POCEH KOCEB]

Great minds think alike!
...Oh wait, was that parroting? Oh well.....

Great minds think alike!
...Oh wait, was that parroting? Oh well.....

 

[chiral.grolim]

I don't generally agree with Chiral, especially on the Bravo 1 handle...

broomstick.

 

[RX-79G]

A better picture of that kukri break: http://www.bladeforums.com/forums/showthread.php/668281-broken-when-chopping!!

The steel was already fractured and rusting prior to the impacts which propagated that fracture to failure, nothing that a cast aluminum handle could have prevented (except by being too uncomfortable for the wielder to use).

You're making my point:

How could it have cracked inside a cast on handle? How would rust get into a cast on handle? The handle would have been fused to the tang a half inch higher - where the tang is considerably thicker.

That's the whole point - when the handle material is bonded to and structurally supports the tang, the tang can't break unless the handle breaks with it.

If you have a soft plastic grip it doesn't do anything to support the tang, prevent water from getting in, etc, that's the kind of failure you're open to.


For shock, there's no reason you couldn't overmold an aluminum handle with rubber. Best of both worlds.

 

[RX-79G]

so what was the point? A handle that can handle a lot of hammer-whacks and be lighter than steel?

Yes. That is exactly the point.

One of the busiest segments of the fixed blade market are the survival knives and choppers that are supposed to be as tough as possible. Despite being tough, people still want them to cut well and balance properly. Because of that, many blades are made of steel much thinner than 1/4", and almost every full tang knife has lightening holes running through the tang. That combination of holes and thinner stock introduces a weekness.

My solution: Use handle materials that contribute to tang strength, rather than lower it because of the necessity of cross pins.

Your solution: Ignore the requirement to balance and cut well, and just use more steel in the tang.


I can certainly understand not being excited about aluminum as a solution, but do you really thing your idea is superior?

 

[chiral.grolim]

You're making my point:

How could it have cracked inside a cast on handle? How would rust get into a cast on handle? The handle would have been fused to the tang a half inch higher - where the tang is considerably thicker.

That's the whole point - when the handle material is bonded to and structurally supports the tang, the tang can't break unless the handle breaks with it.

If you have a soft plastic grip it doesn't do anything to support the tang, prevent water from getting in, etc, that's the kind of failure you're open to.


For shock, there's no reason you couldn't overmold an aluminum handle with rubber. Best of both worlds.

Fracture was already present, hiding it beneath aluminum doesn't fix it, and that makes me wonder how the cast aluminum "bond" to the tang would have held up to repeated chopping impacts... not well, I'd guess. Sorry, failure still would occur.
You can have a soft plastic grip molded around the tang, or tough resin infused between tang and handle-material as well, all sorts of options, most handle scales are glued AND pinned preventing water, etc. from penetrating anyway.
The gerbers had thick aluminum and a thin rubber coating that rubbed/scratched off a bit too easily and didn't insulate well. For insulation/comfort, rubber-overmold needs to be reasonably thick which means the aluminum needs to be thinner to keep the handle the same size whereupon, again, it doesn't really provide much additional strength if the tang isn't strong enough to handle stress on its own. Moras and Gerbers and Kabars, etc. get by with plastic/FRN and rubber-overmold around a sufficiently stout tang (ever seen those D-tests?). Heck, FOLDERS get by with FRN or G10 scales over strong steel liners. Replacing the plastic with aluminum would increase handle strength/durability but won't make up for a weak tang.

 

[chiral.grolim]

Yes. That is exactly the point.

One of the busiest segments of the fixed blade market are the survival knives and choppers that are supposed to be as tough as possible. Despite being tough, people still want them to cut well and balance properly. Because of that, many blades are made of steel much thinner than 1/4", and almost every full tang knife has lightening holes running through the tang. That combination of holes and thinner stock introduces a weekness.

My solution: Use handle materials that contribute to tang strength, rather than lower it because of the necessity of cross pins.

Your solution: Ignore the requirement to balance and cut well, and just use more steel in the tang.


I can certainly understand not being excited about aluminum as a solution, but do you really thing your idea is superior?

Have you seen the I-beam construction of the TGLB? The GSO-5.1 has excellent balance with an unskeletonized tang, as do many others that i could rattle off. I've never seen a stick-tang with "lightening holes" and those are FAR more prolific than the pinned-scale models. Broken mora tangs are rare, as already noted. I also have knives with loveless-style tapered tangs that balance perfectly. All of these are strong, none require aluminum and the addition would not substantially improve their strength. So what i am ignoring? A better question is, what are you ignoring?

 

[RX-79G]

I seem to be re-explaining that same thing over and over, so let me just make one thing really clear:

This is a Gerber MK II stick tang blade.

They've been made like this for 49 years. The aluminum handle surrounds the tiny stick and the wider tang up to a line 1/16" below the stamp.

Has anyone EVER heard of or seen one of these blades break inside the handle?



I would put money on the answer being "no". The handle imparts too much strength to the tang to allow it to move far enough to bend or break.

 

[RX-79G]

Have you seen the I-beam construction of the TGLB? The GSO-5.1 has excellent balance with an unskeletonized tang, as do many others that i could rattle off. I've never seen a stick-tang with "lightening holes" and those are FAR more prolific than the pinned-scale models. Broken mora tangs are rare, as already noted. I also have knives with loveless-style tapered tangs that balance perfectly. All of these are strong, none require aluminum and the addition would not substantially improve their strength. So what i am ignoring? A better question is, what are you ignoring?

The GSO 4.1, which has a shorter blade, does use lightening holes for balance. And the longer one doesn't have a 1/4" tang, either. It's 3/16".

Are you serious about the stick tang having lightening holes? Why the hell would it? It's already light because it is a stick tang.

 

[RX-79G]

Fracture was already present, hiding it beneath aluminum doesn't fix it, and that makes me wonder how the cast aluminum "bond" to the tang would have held up to repeated chopping impacts... not well, I'd guess. Sorry, failure still would occur.
You can have a soft plastic grip molded around the tang, or tough resin infused between tang and handle-material as well, all sorts of options, most handle scales are glued AND pinned preventing water, etc. from penetrating anyway.
The gerbers had thick aluminum and a thin rubber coating that rubbed/scratched off a bit too easily and didn't insulate well. For insulation/comfort, rubber-overmold needs to be reasonably thick which means the aluminum needs to be thinner to keep the handle the same size whereupon, again, it doesn't really provide much additional strength if the tang isn't strong enough to handle stress on its own. Moras and Gerbers and Kabars, etc. get by with plastic/FRN and rubber-overmold around a sufficiently stout tang (ever seen those D-tests?). Heck, FOLDERS get by with FRN or G10 scales over strong steel liners. Replacing the plastic with aluminum would increase handle strength/durability but won't make up for a weak tang.

Are you seriously suggesting that the knife was built with a fracture? It is clearly an impact fracture that cracked it the first time, and finished it off later.


And yes, an aluminum handle would have prevented even a flaw in the steel from breaking.

 

[chiral.grolim]

...Gerber MK II stick tang blade...

They've been made like this for 49 years. The aluminum handle surrounds the tiny stick and the wider tang up to a line 1/16" below the stamp.

Has anyone EVER heard of or seen one of these blades break inside the handle?

I would put money on the answer being "no". The handle imparts too much strength to the tang to allow it to move far enough to bend or break.

So you know, this is how they are made: http://militarycarryknives.com/Knives.htm

The handles are cast in two part molds and have a preformed hole for insertion of the blade tang. After being extracted from the mold, the flash from the handle centerline and the sprue from the end of the pommel are removed. Then a lanyard hole was drilled in the pommel and the hole entrance and exit chamfered to remove the sharp edge. The handle then had the finish applied...

...After heat treatment, grinding, cutting of serrations (if any), sharpening and final polish, the notched blade tang and handle tang hole are coated with a thermosetting epoxy and the blade tang inserted into the handle.

The epoxy imparts a strong bong between tang and handle.

Second, the tang is very stout much like the Mora where, again, the handle or blade fail before the tang, and I've also never seen a wooden mora handle fail and the failed plastic handle is a rare thing as well. What I HAVE seen is how much effort it takes to cause that failure in a Mora. I've also seen how much effort it takes to fail a thick steel stick-tang much stronger than any aluminum. I have yet to see someone test one of these to failure at all. Yo are simply declaring that it "imparts too much strength" without any actual evidence thereof...

 

[RX-79G]

So you know, this is how they are made: http://militarycarryknives.com/Knives.htm

The epoxy imparts a strong bong between tang and handle.

Second, the tang is very stout much like the Mora where, again, the handle or blade fail before the tang, and I've also never seen a wooden mora handle fail and the failed plastic handle is a rare thing as well. What I HAVE seen is how much effort it takes to cause that failure in a Mora. I've also seen how much effort it takes to fail a thick steel stick-tang much stronger than any aluminum. I have yet to see someone test one of these to failure at all. Yo are simply declaring that it "imparts too much strength" without any actual evidence thereof...

I'm sorry, I again wasn't clear enough:

Has any Gerber MKII ever broken a handle OR tang?


I explained what is going on with the Moras, and the plastic handles do break now and then, despite the blades being too light to chop with. But aluminum handles do what plastic ones do, plus are pretty much unbreakable in human hands. The blades with always fail before the tang/handle combination.


BTW, you may well be the first person in history to call a Gerber stick tang "very stout".

 

[RX-79G]

Have you seen the I-beam construction of the TGLB?

I already mentioned knives made by drop forging or billet machining. They are another excellent solution - but a really expensive one.

Most knives are made of ground flat stock in about the thickness of the final blade.

 

[chiral.grolim]

The GSO 4.1, which has a shorter blade, does use lightening holes for balance. And the longer one doesn't have a 1/4" tang, either. It's 3/16".

Are you serious about the stick tang having lightening holes? Why the hell would it? It's already light because it is a stick tang.

You wrote this:

One of the busiest segments of the fixed blade market are the survival knives and choppers that are supposed to be as tough as possible. Despite being tough, people still want them to cut well and balance properly. Because of that, many blades are made of steel much thinner than 1/4", and almost every full tang knife has lightening holes running through the tang. That combination of holes and thinner stock introduces a weekness.

I presented a couple of popular "hard use / survival" knives, could also list choppers, that most certainly do NOT have skeletonized handles, indeed very few do as it requires extra machining and reduces strength. Regarding the GSO-4.1, the newer version will not have this. Stick-tangs are the MOST common and do not have holes, so why on earth would you make such a statement?? As to spine thickness, that doesn't impact cutting performance unless the blade is insufficiently broad - the GSO-5.1 is still a very good cutter despite being even a thick saber-grind as it is 0.020" behind the edge and 5-dps primary. It's also perfectly balanced, many knives are well balanced. What's the problem with the thickness? You need it to be 1/8", there are lots of those as well.

Are you seriously suggesting that the knife was built with a fracture? It is clearly an impact fracture that cracked it the first time, and finished it off later.

And yes, an aluminum handle would have prevented even a flaw in the steel from breaking.

It is a fracture already present in the tang - how and when it occurred is not evident, microfractures often pass QC tests before departing the factory, which is what warranties are for. HOW would an aluminum handle have prevented fracture propagation? What is the bond-strength supposed to be to resist impact shock that welds are known to fail at? Do you have any evidence to back up the claim?

 

[chiral.grolim]

Has any Gerber MKII ever broken a handle OR tang?

Has any ever been tested?