Why no squared spine on Beckers?

Personally I would value a squared spine to begin with from the factory, though its obviously not a deal breaker for me.

And squared spines can be used for more than just ferro rods. They make excellent tinder scrapers (in fact, squared spines make better tinder for catching a spark for a firesteel than feathersticks usually). Plus, when you use them like that, you're saving the sharpened edge for other work.

I also find a squared spine really good at smoothing/sanding a surface. If I was going to be whittling a handle for something, the last bit I use the spine of my knife to soften it up like I would normally do with sand paper.

Oh, and of course the ferro rod striking :p.
 
I use the striker that comes with the fire steel which saves a squared spine for emergency use, as strikers can be lost/misplaced. Back-ups are good. Easy to square, if desired.
 
My understanding is, that a 90 degree edge on the spine actually creates a weakness. Microscopic cracks may form, thus making the blade weaker.
 
I don't really understand the point of your question.

If you refer to the edge being sharp, and by my comment, weak. Then my answer is, that egde it self isn't really subjected to the same lateral stress as a 90 degree spine.
 
Rasmus80 said:
I don't really understand the point of your question.

If you refer to the edge being sharp, and by my comment, weak. Then my answer is, that egde it self isn't really subjected to the same lateral stress as a 90 degree spine.
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Oh my. There's a lot of pseudo science on the internet.

Stress risers occur whenever you have something that would hinder even distribution of force through the material due to area reduction the force is applied to (force concentration).

As far as knives go, typical example would be wide blade transitioning to narrow tang. To help with that you can change geometry, add the material or both (rounding inner corners for example, or make the tang thicker), to help with more gradual transition (force distribution).


Edge of the spine is not an area of significant stress concentration, neither it is area of concern. Spine is usually the strongest part of the blade. Adding material to it will only make it stronger, not weaker.


Lateral forces... Only of concern when chopping, batoning or prying. Stress concentration will occur on the thinner part of the blade. Blade will crack on the edge side first.

If you don't believe it, look at all the pictures of half moon breakages. You won't see many of these on the spine side.

So, as far as strength of the knife is concerned, 90 degrees spine vs rounded, it is not an issue.
 
That may very well be.

I am not making a statement, just refering info obtained from previous treads on the same subject.
 
bghorn said:
Oh my. There's a lot of pseudo science on the internet.

Stress risers occur whenever you have something that would hinder even distribution of force through the material due to area reduction the force is applied to (force concentration).

As far as knives go, typical example would be wide blade transitioning to narrow tang. To help with that you can change geometry, add the material or both (rounding inner corners for example, or make the tang thicker), to help with more gradual transition (force distribution).


Edge of the spine is not an area of significant stress concentration, neither it is area of concern. Spine is usually the strongest part of the blade. Adding material to it will only make it stronger, not weaker.


Lateral forces... Only of concern when chopping, batoning or prying. Stress concentration will occur on the thinner part of the blade. Blade will crack on the edge side first.

If you don't believe it, look at all the pictures of half moon breakages. You won't see many of these on the spine side.

So, as far as strength of the knife is concerned, 90 degrees spine vs rounded, it is not an issue.
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This.

The stress risers that people are talking about being "90 degree corners" are when things go from one shape, abruptly (90 degree corner) to another. The classic example is the Kabar USMC (1217) blade/tang junction. Lots of blades break there because all of the forces for the whole area are forced to go through one small point. When you radius something that transition area becomes much wider, and the forces are distributed.

Funnily enough, this is the exact idea that makes a knife work, but in reverse. Blades concentrate force on a TINY spot on the edge (the apex), and that is what enables it to cut.

Anyway, 90 degree spines shouldn't have any effect on the strength of the knife unless something went horribly wrong with the machining process, or you're somehow cutting deep notches into it. This is because any forces here would be distributed along the whole spine of the knife, as there is not some place for the forces to concentrate by changing dramatically in shape/size.

Side note. I wonder if jimping has ever caused a failure (since that's creating mini-stress risers). Also, I know the buck hoodlum has been broken several times by the notch in the spine (because again, its a place allowing force to concentrate), which would seem to be simply a larger version of a jimp.
 
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Sidenote here as well...

I work with optic lenses, and in order to keep them from fracturing, we "break" 90 degree edges.
If we don't break those edges, fractures form easily.

This is true for both plastic and mineral lenses.

If it is true for those two materials, it is not unlikely that it is true for other materials.

Call it pseudo science if you like.
Or just call it speculation on the matter.
 
Rasmus80 said:
Sidenote here as well...

I work with optic lenses, and in order to keep them from fracturing, we "break" 90 degree edges.
If we don't break those edges, fractures form easily.

This is true for both plastic and mineral lenses.

If it is true for those two materials, it is not unlikely that it is true for other materials.

Call it pseudo science if you like.
Or just call it speculation on the matter.
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For the most part, lens edges are rounded to reduce diffraction and other distortions. Reduced edge chipping on very brittle materials is just beneficial side effect.
 
I have No idea how you could come up with this idea...

Rasmus80 said:
If it is true for those two materials, it is not unlikely that it is true for other materials.
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Every material is different, that is why we build cars and skyscrapers out of steel and not Only glass. Otherwise we could Heat sand and make creating buildings Much more cost effective. Hell, we could even Cast buildings then...
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On a more serious note.

Wouldn't the innate hardness of glass and its lack of ductility be a leading cause as to why this arguement against steel having a 90° angle be all for naught?

I could see that an argument be made for plastics If, and only if, the forces exerted and the rates at which deflection, rebound, hardness and toughness were measured and found to be in scale to a certain type of steel and then the chipping scaled along the same lines of progression.
To make a blanket steel, glass and plastic comparison is no bueno

There are many types of plastics, and I am sure some make a better lense then others (think polycarbonate vs hdpe). So wouldn't those essentially be comparable to differences in steels? Some are more prone to chip (zdp-189), some are more tough (s7, d2). Using my examples here, those that can't take as keen of an edge likely wouldn't chip in the same instance. Steels themselves shouldn't be compared in such a manner (I wouldnt expect a zdp-189 spine to take the abuse of a 52100 spine both @ 59hrc).

I am only stating this because there has been a blanket statement regarding the similarities between steel, glass, and plastics and I don't feel that all that much of a direct comparison can be made. Considering the differences between the three are substantial.

(From here on out, lense grade plastics will be referred to as "plastic" for my fingers ease, typing this on a phone)

-Glass chips conchoidally (likely plastic as well), steel doesn't
-Steel is Much more likely to deform under excessive load, glass and plastic break
-Steel is reactive to elements, at least more so than glass
-Most steels can take a higher side load at a 20° angle or a 60° angle than glass or similar plastics due to the ductility and toughness.
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I would think that glass and plastics aren't all that similar to steel in regards to a knife aside from they can both slice something. That is why we progressed(?) away from knapping flint and chert.
While modern companies cannot make a scalpel as sharp as the edge on a piece of obsidian, they can make an edge that will last significantly longer due solely to being less likely to chip because of steels superior toughness.

Hence a 90° on steel is not comparable to 90° on glass or plastic.
 
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Holy hell a simple why don't Beckers come with a 90° spine question turned into some serious technical mumbo-jumbo. Lol
 
Sorry for the derail folks, as you were.

I squared my 15 in front of the jimping, and my 2 the whole way. But I rounded the spine on my 11 for ease on my thumb and smoothness in pocket when folded.
 
NJBillK said:
Sorry for the derail folks, as you were.

I squared my 15 in front of the jimping, and my 2 the whole way. But I rounded the spine on my 11 for ease on my thumb and smoothness in pocket when folded.
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Folded? What do you mean folded? Pics or it did`nt happen!!!!!!!!
 
Take a look in the Beckerhead knife making and modification thread for my 11, It is on the last page. No need to derail this again.
 
Perhaps earlier I should have said "I doubt squaring a spine would have a meaningful difference in its ability to withstand impact", as I guess I could have come off a bit strong. My bad :(.

I'm kind of a nerd, and maybe I'll go research this, as I find this interesting in general, since I can see the arguments from both sides, but something inside me says that glass and metal just shouldn't be expected to work the same way. Sometimes I wish I had been a material scientist... Anyway...

And two more things (on topic).

For those that use the choils on the larger beckers to strike firesteels... are they that sharp? That, and aren't those choils a bit small for most firesteels?

And I still use the spine of my knife more for wood shaping/tinder scraping than I do for firesteel striking, at least so far. I HAVE though started trying to leave only one side of the spine sharp, and the other rounded. Because while square spines are quite useful, sometimes they are decidedly uncomfortable. So for me keeping the left side of the spine sharp, and the right side rounded seems to work best (I'm right handed, and usually use the knife in my right hand, so the left side would be the part where the action is happening while scraping).

Anyone else do that?
 
No problem :thumbup:

I use the choil on my Scrap Yard Yardkeeper. And the choil is not sharp.
Any edge does not have to be a perfect 90 degrees to throw sparks of a firesteel.
A perfect 90 degree edge does however do a better job at it!

On other knives I have squared only a small part of the spine, some 1 1/2" up the spine, where my thumb does not reach.
 
I have a JK Knives Mini Belt Canadian in O1 @ 60ish hrc and a full height grind and it is the best at throwing sparks out if All of my knives and strikers.

I don't know if it is the hardness, the fact that is it less than a 90° angle, the sharp spine/flat transition, or a combination of all three. But when it comes to me Needing spark for a fire and relegated to using a firesteel, that is my goto knife.
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I would suggest taking a chainsaw file and touching up the sharpening notch to fit your ferro rod and throw a slight angle on it.

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Does anyone think hitting the notch with a dremel and ball bit to put a rounded dish to it would allow one to catch the spark a bit and direct them, or more accurately just aim them into a more specific area instead of a fan shaped spray?

I might give this a shot one day when I am bored...
 
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