Thursday, September 11, 2014

Becker BK7 vs the Ka-Bar USMC fighting knife

This came up over on the Ka-Bar forum.  A member had his Ka Bar break just above the hilt while chopping down a 3-inch birch tree.  He seemed willing to accept that this wasn't normal for the knife but someone else suggested the "hidden tang" comprised a design flaw.  I bring most of what I said over here because I mention the BK7 a lot:

Yes, the Ka-Bar fighting knife doesn't have a full tang, but the fact that the tang goes all the way to the pommel apparently counts for a lot. This knife went all the way through WWII and the Marines who used it for all sorts of things loved it. Ethan Becker's BK7 was intended to be an improvement over the Ka-Bar fighting knife, and it is in the sense that it can take more abuse without breaking, but the Ka-Bar could take quite a lot of abuse without breaking. In fact I have been on the lookout for comments about this knife over the years and the one [on the Ka-Bar site] is the very first I've heard about its breaking.

I am a former engineer and while I'm not sure all this was taken into consideration by the Marines, the Air Force in buying a weapon system doesn't pay for indestructibility. An airplane that is 100% safe would be so heavy it couldn't get off the ground; so they insist on a set of procedures to compensate for the risk. All structure wears out for example; so they either insist on periodic tests or "R&R," remove and replace at given intervals. But before that they insisted that McDonnell Douglas, for example, demonstrate that the aircraft met the established requirements.

As to the Ka-Bar USMC fighting knife I imagine it satisfied the initial requirements. There would have been some sort of testing and it obviously satisfied the tests. However, it should be borne in mind that the manufacturer couldn't be 100% sure that every knife that came off the assembly-line was as good as the knife or knives tested. So what would the military have asked for in the way of QC?  Testing every knife? Not practical. Sample-testing? More likely. Depending upon how many knives were being churned out back then QC could have looked at an agreed upon number. Or, maybe the military just left it up to Ka-Bar's standard practices which have been pretty good over the years.

So, did this particular knife-break demonstrate that all Ka-Bar knives would break if someone tried to cut through a 3-inch birch tree? I think it more likely that the one that broke was a manufacturing anomaly. Such anomalies probably occurred in WWII as well but must have been pretty rare else this knife wouldn't have come through that war with such a good reputation.

Now, having said all that, Ethan Becker intended the BK7 to be an improvement on the Ka-Bar. It weighs 13 ounces to the Ka-Bar's 11. It is made of thicker steel. I'm not clear on whether the steel is better than that used on the Ka-Bar from WWII but the design is more confidence-inspiring. But to be fair to the Ka-Bar, the BK7 is being tested today (see several Youtube videos) for cutting through things like birch trees. The USMC would have been more concerned about fighting and an 11 ounce 7-inch bladed knife could be wielded more quickly than a 13-inch 7 1/2 bladed knife.

I was in the Korean War and not WWII, but we used the same equipment (minus the Ka-Bars. We were not issued anything other than bayonets). But I just got out both my Ka-Bar and BK7, put them back into their sheaths and have to say that if I were going back into a WWII or Korean-War situation I'd rather carry the Ka-Bar than the BK7. Not only is the Ka-Bar a lighter knife, but the sheath is lighter as well. The knife and sheath at 15 1/2 ounces weigh less than the BK7 and its sheath: 1 pound 2 ounces. If you are going to hike (march) all day than you opt for lightness over indestructibility if you have a choice.  As long as you aren't giving up too much.

In a modern war where you ride to battle in a Humvee and don't have to march all that far, maybe you can afford a bit more indestructibility.

If I had to get in a knife fight today (which I will dearly try to avoid especially since I'll be 80 next month ) I'd probably use my Ka-Bar over my BK-7, or perhaps I'd hope to overawe him with my BK9, but on my hikes, while I am trying out the BK2 at the present time I expect that eventually I'll prefer my BK17.


Unknown said...

The Kabar knives are the best for outdoors survival trips like camping, trekking.

Asifur Rahman said...


Jerry Gonzalez said...

Yeah, I'd probably use my Ka-Bar over my BK-7 too!