Question for BKC from a long-time Axis nerd re: variance between Axis models...

Professor

Professor

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I've noticed that the Bone Collector's blade tang ramp where the Axis module interfaces is radiused, which in my estimation reinforces the three point blade contact between Axis module, pivot pin, and stop pin, making for rock-solid lockup with absolutely no vertical blade play. The mini-BC is fast becoming my favorite EDC of all time.

Other Axis models I own, inclusive of the large Onslaught, Adamas, and H20 folder all have a hint of vertical blade play and they do not have the radiused area on the blade tang, just a flat ramped interface surface. My Adamas in particular has play that simply will not disappear no matter how much the pivot is adjusted or if I allow the Axis module to "slingshot" forward when the blade is opened, which on other models will tighten the lockup and reduce or eliminate altogether the vertical play. There exists absolutely no side to side play on my Axis models as I've adjusted/Loc-Tited the pivots to my preferred "hydraulic" opening and closing feel.

My question is, does BM plan on incorporating the (IMO "improved") radiused blade tang ramp on other/all models at some point? Perhaps you are already, and I just don't own those models.

Thanks for your response, and by the way, I'm very pleased that you have a presence here now! Hope to see you at Blade this year.

Prof.
 
PS: One other factor that I believe impacts the existence of vertical blade play in an Axis-equipped folder is the relationship and distances of the Axis module, stop pin, and pivot pin. On the Adamas, the stop pin is further back, putting it closer to the Axis module than on my other knives, which I suspect is what's behind some of the vertical rock.

When I hold the Axis module back (blade floating free of it) and check for "pivot slop," there is no more or no less than on any other Axis folders I have. This pivot slop is completely absorbed on my BC's, which, according to my theory, is mitigated by the enhanced three-point contact.

Told you I was a nerd.

Prof.
 
Here's a masterpiece of an illustration of the blade tang radius I'm talking about found on the BC models:

IMG_1107[1].jpg
 
Thanks, man. I'm not too sure BKC is gonna agree. I'm thinking my amateur lock science may be deemed more a PITA. :)

Here's another masterful illustration of the 3-point lock interface (areas in red) I'm referring to on the mini-BC. The Axis module is the wedging catalyst. The choice of 410 stainless for Axis module and stop pin are perfect since they are hardened yet just slightly malleable, and of course, stainless!

IMG_1108[1].jpg

My theory is, it is the distance between these three points, along with the inclusion of the radiused tang ramp, that make for rock-solid lockup on the BC's. The Adamas' not having the radiused tang ramp, along with the much closer proxity of the further-rearward stop pin and Axis module of the Adamas, make for the vertical play, according to my theory, of course.

Do other models have the radiused tang ramp? How about the Presidio models?

Prof.
 
My assertion is that the distance between points 1 and 2 (A), combined with the positioning of point 1 (forward of, behind, or directly over), makes all the difference in whether vertical lockup is going to be solid or not in regard to the Axis. Lateral stability is the only variable impacted by pivot adjustment.

This illustration ain't the greatest, since the stop pin on the Adamas is actually slightly behind the pivot, though the distances are still representative:

IMG_1110[1].jpg

I'd love to hear others' thoughts/theories as well! I can't be the only lock nerd around here.

Prof.
 
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Professor,
I will have to defer to our engineers on this one. I will get back to you as soon as possible with an answer. It may be Monday or Tuesday depending who I still have in the office today. Thanks for understanding,
 
No problem, and thank you for responding!

What prompted this "study," if you will, was my 12-year old Son's use of the Adamas and noticing the vertical blade play after he went out and thumped on it in our back yard (trees, trees, and more deciduous trees). We like to trade things, he and I. Casio watches, knives, flashlights, you name it. Well, he somehow ended up with the Adamas. He loves the robustness of the build, as do I.

He EDC's a mini Bone Collector dressed in black G10 (while not in school, of course), and I EDC one dressed in green/black G10. He's had the mini BC for some time, and I found it interesting that the Adamas developed pronounced vertical play in one day of use that his mini BC never has. It's a testament to the mini BC design and execution, since while he does not abuse them, he's not afraid to chop, carve, cut rope, etc. for his tree forts. My mini BC also has zero play, having been EDC'd since April of last year.

Anyway, all this got me a'thinkin' about the Axis design and its execution on various models. The Adamas (I still think of Lorne Greene every time I type the word) is the only Axis knife I know of with the locations and proximities of the aforementioned 3 points of contact, and it's the only one I've ever had that's developed this level of vertical blade play.

I used to infrequently chat back in the day with Bill and Jason at the "Skunkworks" as they called it. They are true innovators IMHO.

Prof.
 
Professor said:
My assertion is that the distance between points 1 and 2 (A), combined with the positioning of point 1 (forward of, behind, or directly over), makes all the difference in whether vertical lockup is going to be solid or not in regard to the Axis. Lateral stability is the only variable impacted by pivot adjustment.

This illustration ain't the greatest, since the stop pin on the Adamas is actually slightly behind the pivot, though the distances are still representative:

View attachment 327926

I'd love to hear others' thoughts/theories as well! I can't be the only lock nerd around here.

Prof.
Click to expand...

Since you asked. I see it as the relationship between C and B or the ratio. If you take B/C the larger that ratio is the tighter the lockup due to leverage. That does require that the AXIS lock pin make contact with the flat or radiused shaft/tang near the middle or preferably the beginning of the AXIS locks nature play.
 
This is great Professor, once again I reminded of how little I know about knives and their inner workings compared to some people. BF is a great place to learn.
 
Great question, I too look forward to the answer, engineers like sounding smart ;) so I'm sure it'll be a good one.
 
Nice to see you over here Skimo, send me a PM sometime to catch up. And yes I am also eager to see what Ryan's response will be on Professor's inquiry.
 
gga357 said:
Since you asked. I see it as the relationship between C and B or the ratio. If you take B/C the larger that ratio is the tighter the lockup due to leverage. That does require that the AXIS lock pin make contact with the flat or radiused shaft/tang near the middle or preferably the beginning of the AXIS locks nature play.
Click to expand...

You've nailed it, Sir. It's all about leverage's impact on lockup as the result of the proximities of the three points of contact from one another, and that radiused area definitely makes a difference IMHO.
 
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Still hoping for a BM engineer's perspective on this...

Thanks in advance.

Prof.
 
Cool thread. I like engineering stuff like this. I think most of the folks here are right on with their theories. Can't wait to hear from BM.
 
Professor,
I have an answer for you from our engineers:

1. Regarding the "radiused" tang ramp improvement: The Bone Collector AXIS geometry does not actually utilize a radiused tang where it locks up. There is a flat plane (where the lock stud actually interacts with the blade) and a radiused section that does nothing as far as the lock is concerned. The radius is solely there to increase the cross-sectional area of the blade around the pivot. In other words, the lock stud never reaches that radius. Actually, having the lock stud interact with an increasing radius would decrease both the strength and stability of the lock.

I think that should clarify any confusion. The Bone Collectors use the same style of lock geometry as the rest of our AXIS locks.

2. Now for the lock triangle geometry: The original poster was correct in his theory. Increasing the lengths of the "legs" of the lock triangle (distance from pivot to lock stud, pivot to stop pin, stop pin to lock stud) does generally make for a more stable lock. The most important thing to keep in mind is that we engineer all of our knives to meet the intended customer’s needs. Some of the extremes are very small gent knives which have smaller components and a smaller envelope of space for lock-up geometry as opposed to our larger heavy use folders with more space for not only larger lock-up geometry but larger components as well. These are only some of the other factors at play, but of course, the main goal is to maximize the resistive moment arms of each component with respect to the pivot of the knife. The larger the triangle the easier the components can resist forces applied to the blade. This is what you feel when testing for up-and-down tip wiggle (vertical play).

I hope this answers your question. I have also posted this on our company forums. If you have further questions check out this link:
http://benchmadeforum.com/eve/forums/a/frm/f/558000917001
Our engineers are available on there to answer more in depth questions. I will cross post here as well so we can build a strong database of information.
 
Great answer, and thanks. One of the things I've noticed across my very large accumulation of different Axis lock knives is the difference in what I guess you'd call the "detent," which is in reality the shape of the lower portion of the lobe on the blade tang. Other than "it is what it is, we take it as the engineers/designers spec it" I'd be interested in any comments from Benchmade. :thumbup:
 
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