CBT...?

[iamtoast]

I am under the impression that, for most road tires, grooves are there to help channel water so the rubber stays in contact with the road. Otherwise the tire can skip over the surface of incompressible liquid that cannot flow out of the way fast enough.

Slicks on sports cars can decrease lap times impressively but driving them on a wet track = street pizza.

 

[lex2006]

I think the way it works to strengthen the blade is like corugated cardboard the ribs make it more ridged. They also add more surface area while reducing the part that would add friction cutting and chopping . Also agree that this probly works best with hard materials .

 

[PeteyTwoPointOne]

I think the way it works to strengthen the blade is like corugated cardboard the ribs make it more ridged. They also add more surface area while reducing the part that would add friction cutting and chopping . Also agree that this probly works best with hard materials .

Submitted for your consideration, two scenarios....from the Twilight Zone <cue the theme music, Waldo>

Scenario #1...Yeah picture this...imagine you "erase" the CBT on, say, my HG55 by grinding down the peaks until all that's left is the valleys and the blade now looks like a thin as hell Full Flat Grind blade.
You find that you have something that's close to an anorexic or boney Busse blade. A good blade but not as robust and rigid for prying as it was previously before CBT erasure.

Scenario #2...Now think about the opposite...begin with my original 55 still with CBT and magically pour molten INFI into the valleys of the the CBT and you level it off till it's even with the peaks of the CBT rigdes. You find yourself with a more stout blade but you've added mass, and effectively, weight.

It is my opinion <humble, honest, and pathetic as it is > that when I view CBT as "strengthening" a blade, I look at it from the perspective of scenario #1. That is I have a blade that's thin and really excellent at slicing, but I "add" reinforcing ridges <The CBT> that are nicely contoured to avoid stress risers, to boot! It excels at what a knife if PRIMARILY designed for-- slicing...but has some ummmpfh behind the edge if called upon.

I look at it from this viewpoint because when I lowered the EDGE on my 55, I was fascinated at how the "ridges" on the CBT got "erased" by grinding and I was left with a fairly acute laser-like slicing edge. In essence, I have the best of all worlds...a slicer with a rigid spine-- a blade thick enough to breach a painted shut window but not as heavy as a wrecking bar. Take a look at how the CBT "melts" away at the edge....GOOD STUFF!!!

It's good looking to me...not everyone's cup of tea, I recognize...but I love it. But the best thing about CBT is that it's like an onion of Busse engineering...it's many layered and when you peel back one layer you find another layer of genius beneath, supporting the previous layer!

 

[drift draft]

I think I’m OCD for CBT but I’m also dyslexic so maybe its CBT for OCD.

 

[dogboye]

I'm surprised a mechanical engineer (or structures, or materials... some engineer) hasn't weighed in on this. Or maybe one has and I missed it.
From what I remember from my material, structures, and mechanical engineering classes (I've done mostly aerodynamics and controls for the last couple of decades), the key attributes of the CBT are going to be that it maintains the rigidity and strength of a beam (blade in this case) the same thickness as the peak thickness of the blade, while reducing the weight of the blade. So, in a blade where the CBT runs longitudinally along the blade, the blade will be just as strong from handle to tip as a blade that is the thickness of the CBT ridges. Yet the blade will be lighter. They act a little like a single fuller. One would have to do a detailed analysis of the material properties and the geometry of the blade, of say the TGLB vs. the Forsaken Gemini, to say which is more effective, a single fuller or the CBT. And it would change depending on the depth of the fuller, or the depth of the CBT grooves, number of grooves, etc.

I could also believe it affects the tendency of a blade to bind in hard materials. But I am skeptical it affects binding in softer materials (meat), and could very well increase drag, as I think the meat would flow (for lack of a better term) into the grooves, which have now effectively increase the surface area on which the friction can act. I do NOT believe it would be significant, though.

Regarding the HG55 CBT, though... I just don't get what that is for, other than looks. The edge DOES look QUITE cool thinned out like that.

 

[Currawong]

I'm guessing a bit here, but...

When chopping, a blade flexes, producing a vibration or harmonic. The longer and thinner a blade is the worse it gets. This makes it uncomfortable to use (via the transmitted shock or vibration), decreases chopping power (via diffusing energy away from the point of contact) or increases likelihood of breakage (via the harmonic).

You can fix these problems by making the blade thicker, but doing so also makes it heavier, reducing the snappiness of the blade and increasing fatigue, and as Petey2.1 mentioned it will be less slicey.

So I'd guess the CBTs give you a blade that operates like a thick knife under heavy impact, but operates like a thin knife in other respects (fast, non-fatiguing and slicey).

 

[iamtoast]

Reminds me of the flutes cut into some firearms barrels. The done increase rigidity when compared to a barrel the same diameter as the flute peaks but can be useful for heat dissipation and decreasing mass (weight). Only when compared to a barrel the same diameter as the troughs does the 'addition' of the flutes (magically added on) increase rigidity. Sure looks nice either way. Can also be compared to an I beam to a solid block of steel.

 

[blackhat]

Saying CBT reduce the friction of cutting is like saying tire thread is for reducing traction... is obviosly work opposite.

Tread does reduce traction, that's why race cars use slicks (more surface area = more friction). Tire tread is only there to handle channeling of water (incompressible) so that the tire remains in contact with the road when the road is wet.

 

[ipal]

I like Pete"s observation on how the CBT on HG55 increase thickness of otherwise very thin slicing edge.
But I also shared Dogboye's believe that to add lateral strength the CBT should be horizontal along the blade (not vertical from spine to edge).
Many of new models from Busse have the CBT, but none of them have vertical CBT (yet).
It will be interesting to hear from Jerry how the vertical CBT performs in term of lateral strength.

 

[COPIUOS]

Submitted for your consideration, two scenarios....from the Twilight Zone <cue the theme music, Waldo>

Scenario #1...Yeah picture this...imagine you "erase" the CBT on, say, my HG55 by grinding down the peaks until all that's left is the valleys and the blade now looks like a thin as hell Full Flat Grind blade.
You find that you have something that's close to an anorexic or boney Busse blade. A good blade but not as robust and rigid for prying as it was previously before CBT erasure.

Scenario #2...Now think about the opposite...begin with my original 55 still with CBT and magically pour molten INFI into the valleys of the the CBT and you level it off till it's even with the peaks of the CBT rigdes. You find yourself with a more stout blade but you've added mass, and effectively, weight.

It is my opinion <humble, honest, and pathetic as it is > that when I view CBT as "strengthening" a blade, I look at it from the perspective of scenario #1. That is I have a blade that's thin and really excellent at slicing, but I "add" reinforcing ridges <The CBT> that are nicely contoured to avoid stress risers, to boot! It excels at what a knife if PRIMARILY designed for-- slicing...but has some ummmpfh behind the edge if called upon.

I look at it from this viewpoint because when I lowered the EDGE on my 55, I was fascinated at how the "ridges" on the CBT got "erased" by grinding and I was left with a fairly acute laser-like slicing edge. In essence, I have the best of all worlds...a slicer with a rigid spine-- a blade thick enough to breach a painted shut window but not as heavy as a wrecking bar. Take a look at how the CBT "melts" away at the edge....GOOD STUFF!!!

It's good looking to me...not everyone's cup of tea, I recognize...but I love it. But the best thing about CBT is that it's like an onion of Busse engineering...it's many layered and when you peel back one layer you find another layer of genius beneath, supporting the previous layer!

This is a good illustration of how to think about it, I think, and yes - this is a twilight zone conversation...always is, it seems!!!

I think there would have to be so many controlled tests to disprove a hypothesis that this conversation will go on and on as it seems to have been going on for awhile.

For my uneducated other than use and observation/experience using different materials in the past for various and sundry stuff, from a logical/reasonableness standpoint, the lateral (going with the blade) I-beam theory seems to make sense.

On the HG55 deal, that thing ain't goin' nowhere...it is a freaking 1/4" thick to begin with. One of the most solid knives of its size out there. I have an FFG and a MO, and the MO feels beefier (as it should by looking at it, and theory)...and I had an LE (Full Apple Seed Convex, like the Boss Jack .22" Full Convexes, only .25") that was so freaking hefty, I passed it along. This seems to corroborate the P's theory...and I do believe that it takes much less work to achieve slicy-ness on MO-style CBT and the knife is still a beast in hand. You would have to completely re-profile the Full Convex...

 

[MikeH]

I am not a mechanical engineer. Will an electrical engineer who for several years managed a materials test lab, including a hydraulic test bed capable of breaking wood and concrete poles and pulling steel wire in two, suffice?

First of all, lets dispense with the corrugated steel question. Corrugated steel is bent into shape, it does not have steel cut away, and is in no way analogous to CBT. One has nothing to do with the other.

John the Texican has it right, it is solely a matter of strength per unit of weight. If you take a 1/4 inch knife blade and cut longitudinal grooves in it, it is not as strong as a 1/4 inch blade of uncut steel. However, if you cut it to the same weight as a thinner piece of steel, the CBT steel is stronger than the thinner knife of the same weight, on an axis perpendicular to the CBT cuts. I am long retired, or I could prove this on our test bed by sacrificing a few knives.

The words in bold are the reason most CBT is cut parallel with the blade length, achieving the desired effect. The CBT cut parallel or at an angle to the blade length has a very substantial non-CBT spine to maintain acceptable strength.

It is my opinion that, when it comes to INFI knife blades, we have here a case of what Jeff Cooper called PII (preoccupation with inconsequential increments.) Any Busse INFI knife is going to be plenty strong and overbuilt for any reasonable, and some unreasonable, uses, and I don't worry about it.

I an EE won't suffice, we have an experienced physicist available. Maybe Old Physics will chime in.