My bk2 broke under the scales!! WTH!

Let me temper the statement I'm about to make with a disclaimer- I don't think that this should have happened with as thick of a slab of steel as that is. However, stuff sometimes goes down that shouldn't have gone down- there's no way to avoid it. Knives are tools, and tools occasionally break, regardless of how well they're made or designed.

All of that said, IF a BK2 was to break, that's where I'd put my money on it breaking. If you look at the tang of a Becker without the handles on, it's skeletonized except for one piece of steel (a cross member if you will) for the center bolt, and that front bolt is, for all intents and purposes, in the blade slab. The transition between blade slab and skeletonizing, coupled with the fact that the batoning you were doing put a large amount of stress on that area, is more likely to cause a fracture there than anywhere else on the knife. It's just energy from the baton trying to escape in the easiest way possible. That knot made the strikes into the wood dead, and the stress and energy had to find another way out- ideally, it would be through your hand and arm in the form of vibrations, but in this case it was through the point in the blade with the least amount of steel, near a transition (which will be a stress riser).

It's unfortunate and surprising that the break happened, but if the break was to happen (which, again, surprised me- there's a thread on here somewhere where someone batoned through a lawn mower with a BK2 with no ill effects) that placement isn't all that far-fetched.

If I have flaws in my theory, please correct me... I'm no mechanical engineer and I don't have a superb understanding of physics. Just putting my idea out there. I'm glad that it was taken care of, and I'm still going to use my Beckers and whatever Beckers I buy in the future just as hard as I did before. They're great knives, and this was honestly a freak occurrence IMHO :)
 
the flaw was likely the heat treat for the transition zone.

aka a manufacturing defect, which KaBar seems to be owning, and will replace

in 1000s and 1000s of product, esp when there might be a change in process, a couple mistakes happen

the batoning technique was far from ideal, but the knife should not have broken.

edge case, as it were.

fixed.

can we move on? ;)
 
JTmisterknifeguy said:
Thanks, 😀
Means a lot man!
I'd like to join the BK&T clan, I looked at Moose's "let's roll" thread and I think I meet the requirements...
No BF speeding tickets, I actually own a few Beckers (and love em!), and I've posted quite a bit the Becker subforum....
...can't quite remember what else there was, if anything...
If a blooded Beckerhead could point me in the right direction, I'd love to jump right in! 😌
Click to expand...

well, if you read the moose thread, you saw the rules. get at it.
 
Man, I leave for a week and things go nuts around here. The RBK comes out, then a BK2 breaks?

Its already been covered though. There was no doubt in my mind that the knife wouldn't be replaced, and I see that my trust has not been misplaced. The warranty is worded such that they don't have to replaced purposely broken tools (and throwing), but other than that I've not yet seen a Kabar/Becker breakage not handled by warranty.

The breakage was in the HT transition zone, which as has been noted, has happened a few times. Personally I don't count those as a real "failure" of the knife. Meaning, if the HT was off, any knife could/would have broken (doesn't matter who manufactures it, there is always a chance that QC could have missed something and a knife with a bad HT sneaks out). My personal thoughts are that it wouldn't have mattered if it had "windows" cut out of the tang or not, as the problem was with the HT, not the design. I'm sure we've all see photos of knives with full tangs (no "windows") that have broken clean through as well, and I don't hold the HT their at fault for the knife either (at least not all of them. However IF there was a knife in the Becker lineup that didn't need them, then the BK2 would be that one.

I've beat my BK2 through stuff that looks worse than that the log that broke this one, and while I don't do that anymore (its way, way less energy to choose straight grained pieces and split one or two of those and just burn the rest), I think it should have been able to handle that pretty easily.

Anyway, this is another reason that I strongly suggest that ANY tool you buy should be tested in a way that represents how you expect to use it "in the field" BEFORE you need it to perform. That way any potential failures/defects/etc are found in relative safety, and any kinks are ironed out before you "really" use the gear. This goes for knives, and just about anything else to be honest. I did the same thing with my hammock setup (set it up in the car port 4-5 times getting it setup the way I wanted before I ever camped in it).

Anyway, glad its all been sorted out :).
 
This may be the stupidest comment ever, so please forgive. Would it be possible for the company to manufacture metal pieces that could be locked in and epoxied to those handle holes (sold as a mod kit maybe). Would that even make a difference in reinforcing or giving strength to this area of the knife? Like I said sorry for ignorance but was trying to think of an easy mod that would help extremely heavy users....and I am drinking a little tonight:)
 
Unlikely, IMO. A lot of what makes the skeletonizing weaker is that it provides extra potential for stress risers in those areas. You're perfectly happy using a small knife with the same amount of steel in a non-skeletonized full-tang as there is on one side of the BK2 skeletonized tang, after all. IMO the worry over skeletonized tangs isn't that metallurgically sound outside of that possibility. Sure, more metal is stronger. But then, so is having permanent handle scales; then the epoxy helps distribute the shocks into the handle scales, rather than having the only connections be around the screws.
 
zeedeegood said:
This may be the stupidest comment ever, so please forgive. Would it be possible for the company to manufacture metal pieces that could be locked in and epoxied to those handle holes (sold as a mod kit maybe). Would that even make a difference in reinforcing or giving strength to this area of the knife? Like I said sorry for ignorance but was trying to think of an easy mod that would help extremely heavy users....and I am drinking a little tonight:)
Click to expand...

You might try removing one of the scales and filling the void with J-B Weld.

n2s
 
crimsonfalcon07 said:
Unlikely, IMO. A lot of what makes the skeletonizing weaker is that it provides extra potential for stress risers in those areas. You're perfectly happy using a small knife with the same amount of steel in a non-skeletonized full-tang as there is on one side of the BK2 skeletonized tang, after all. IMO the worry over skeletonized tangs isn't that metallurgically sound outside of that possibility. Sure, more metal is stronger. But then, so is having permanent handle scales; then the epoxy helps distribute the shocks into the handle scales, rather than having the only connections be around the screws.
Click to expand...
This is a seperate tangent but I'd be curious to see how much strength/failure reduction could be gained by crowning/chamfering out the cutouts/bolt holes to reduce those stress risers versus filling the voids.
 
I'm not an engineer (hindsight is a bugger), but IMO the cutouts, already being rounded, rather than having hard 90 degree angles in them, won't benefit from crowning/chamfering. Plus it would add to the production steps/effort, whereas just leaving the tang solid is stronger (more material and no stress riser areas) and takes LESS tooling or effort. The older design was a win-win IMO, but as already pointed out, it's actually a production issue more than a design problem, but as a guy who personally loves things over-built, I'd still love to see the return of the solid tang for this particular knife model.
 
52100 said:
I'm not an engineer (hindsight is a bugger), but IMO the cutouts, already being rounded, rather than having hard 90 degree angles in them, won't benefit from crowning/chamfering. Plus it would add to the production steps/effort, whereas just leaving the tang solid is stronger (more material and no stress riser areas) and takes LESS tooling or effort. The older design was a win-win IMO, but as already pointed out, it's actually a production issue more than a design problem, but as a guy who personally loves things over-built, I'd still love to see the return of the solid tang for this particular knife model.
Click to expand...

Im no fancy engineer either ;) but what I'm referring to is the hard edges around the holes, yes the holes don't have 90% corners, but the edge around the circumference could be a potential stress riser. At least this is what I was taught when drilling holes in a knife tang you chamfer them to make them stronger.

Also I'm thinking more after market modification vs production process.

It's probably negligible, but it would be interesting to see. I also would like to see the load limit on a full tang vs skeletonized. Again just interested from a "data" perspective.
 
It would have to be done pre-heat treat to have any real effect, I would guess. The issue is what happens as the crystalline structure of the blade changes. That's why, in this one, you can see the discoloration that indicates a change in structure.

As for the load limits, think about how much force it would take to snap a screwdriver shaft in half. That's a pretty comparable size to just one part of the BK2 metal. I'll grant you, the screwdriver is likely tempered much softer. But there's a good reason we only see a tiny handful out of thousands and thousands of knives break, and then pretty much always because of inconsistencies in the grain structure. When the HT is done perfectly, there's going to be very little difference unless you're deliberately abusing your knife, and even then there's a good chance it won't break. I mean, heck, it's fairly challenging to snap a pencil in half, and that's soft wood, not steel.

Skeletonizing is about weight and balance. For the same profile, if you didn't skeletonize, the balance point would be considerably further back handle-side in the knife, probably by around an inch. The point of percussion would change also. The knives would NOT handle even remotely like they do now. You can't just change the distribution of material and expect the knife to handle and perform the same.
 
I heard from Customer Service, and a new bk2 will be forthcoming in the next few days. Truly remarkable service and professionalism from uncle E and Ka-Bar.
Customer and potential Beckerhead for life!
 
Hey Gents,
Take a looky-Lou at what the nice man in the brown clothes brought me from the nice people with the magic steel...



Wow, it looks even sharper than my old one.
Impressed doesn't begin to describe me right now...

When I got my first Becker, my 9, I said that I owed Ethan a steak dinner.
Well, that debt is now owed thrice over on my part.
I'm not used to customer service like this anywhere, courteous, professional, and prompt.
It's Kabar's Beckers for my fixed blades. They're simultaneously my users and the crown of my collection. :)



Even though my old one broke, deemed a poor heat treat issue, this thread should be all the nudge you need if you're on the fence with Becker/Ka-Bar.
I hope folks read this thread and buy at least a couple, or like cereal box toys, collect them all!
I know that my next several fixed blades WILL be Beckers.
I think this is all the advertisement a guy would need.
They'll really take care of a guy, even a dork like me who has so much to learn.
-JT
 
Good deal man, but damn, haven't even taken it out and used it yet?
 
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