Hunt Full Time

Single bevel heads are not talked about much. They're not sexy, but it's the only head known to have gone thru the shoulder of a cape buffalo. It will literally blow thru the shoulder of a whitetail.
Check out this article and pictures of why it penetrates better than any other type head at AlaskaBowhunting.com

Randy VanderVeen

Dr Love

Some interesting stuff. Never put any thought into the idea of single bevels being the only blade that continues to rotate after impact.

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Booner

I have studied these heads so much this year it is crazy...haha. I am so intrigued by them. I love the heavy grains and the penetration power. You loose speed in the process....but I guess it is a give for a take.

TheOutdoorFever

Those single beveled heads seriously do blow through bone. I love that picture on their website of that shoulder bone with the crack all the way through it the size of the grand canyon.

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Hunt Full Time

These single bevel heads come in lighter grains also.
If you check out the Samurai heads on their site,
you can get them in 100, 125, 150........

Most broadheads work great and will take down an animal
when the shot placement is good. But I like to think how
my heads will do when the shot goes wrong.
I don't want to travel on an out of state hunt only to have
a misplaced shot and then have to spend my time looking
for a wounded animal with no exit hole and little to no blood,
when I could be spending my time in a treestand hunting.

Check out this site with a link to a broadhead test with detailed pictures of split bones: HuntFullTime.com

Pick a head for shots that go wrong, not just when everything goes right.

Randy

Arrowds

With so much effort aimed at demonstrating larger mass develops more momentum, hence deeper penetration. Of course it stands that such penetration thru the bone of a cape buffalo is accomplished.
The reality of engineering is that should all variables be equal to the projectile/broadhead despite such minute differences of single vs double bevel edges.....the results will be identical for that exact shot sequence based upon the larger content of momentum and how that particular bone grain splits upon receipt of that energy. To say based upon one iteration this aspect is of a higher level of performance delivery capability than any other design option is really not being fair to the less educated on this science. The one result obtained is similar in scope to that variable experienced in simply practicing shooting arrows into a target. To achieve a robin hood with one arrow into another happens....just as in one instance passing thru such a tough bone was achieved..although to then extrapolate and assume that particular brand of arrow is the best is assumptive at best and only based upon emotional attachement to that "Brand" based upon achieving that moment of duplicate shot placement rewards.
The fact remains even one 32nd of an inch difference in shot placement on a bone coupled with the particluar 360 degree rotation/moment of alignment of the blades with respect to the grain of the bone have significant impact to the outcome of such goals of completely penetrating the bone.
Please consider one aspect never taken into account of such a test methodology as Dr Ashby has undertaken. Compressible cutting width designs.
Given all variables being identical to mass, velocity, density of material being penetrated on the animal with such variations as hair/hide/muscle, bone, soft tissue vitals...and specifically via this focus on the bone before getting to the vitals/exit wound thru bone after transiting the vitals.
What then do the assumptions become when you transfer such forcing of the full cutting width of a broadhead thru bone (Non Lethal entity) with equal magnitude of momentum in direct comparison to those efficiencies should the broadhead have the capability to reduce its cutting width to minimize deflection/reduce magnitude of energy required to transit the bone completely? Yet return to full width upon pressure being relieved from those cutting edges after passing such bone? Minimizing greatly that deflection of rigid cutting width heads, maximization of straight line penetration which enhances more fully the use of available kinetic energy for more straight line and deeper penetration results. The old theory of mass in motion works...but it is another step into the future when you can amplify the efficiency of such mass in motion thru non lethal entities via "Wedge" width reduction. You reduce the width of a wedge...it penetrates exponentially easier with less energy...you remain a wider wedge...it takes more horsepower to achieve the same moments of distance penetration values.
I'm hopeful this comment is posted and simply reviewed for what it is upon this forum...an honest discussion with a differing point of view with efforts to that of discussion of such factual, science proven variables/results as has been garnered in over 18 years specific study on the subject of forensics/broadheads. And what I assume is the main focus of this new forum standard.

Booner

Thank you for your point of view Matt. It will be taken as that and we appreciate you offering it. Discussion is good.

Andy

Right on dude!

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Hunt Full Time

Arrowds,

After getting out my dictionary for a few of those words, your point is well taken.
However the penetrating ability of a single bevel does not lie in greater mass being imposed upon the bone, but rather by it's twisting action as it goes thru bone, splits the bone open to eliminate the bone from causing drag on the arrow shaft as it passes thru. Whereas a regular double bevel head will make a hole in the bone, the integrity of the bone remains, allowing it to generate a "squeezing" type pressure on the ferrule of the head and the arrow shaft as it tries to pass thru the bone.

A good example of this is if you tried to push an arrow with a two blade double sided bevel broadhead thru a stick of celery (making sure the blades were parallel with the celery), the celery would have a hole with a slit on each side of the hole. The celery would still be rigid enough to apply a "squeezing" type pressure to the arrow shaft as it passed thru, causing drag.

But if you use an arrow with a single bevel head on it and push it thru the celery, it's going to twist (or turn) as the head passes thru. By the time the whole length of the head passes thru the celery stalk, it will have split open, creating a long crack length wise in the celery which then it can no longer squeeze or restrict the arrow shaft from passing thru more easily.

In other words, a lighter grain single bevel could pass thru an animal more easily than a heavier double or 2 sided bevel head because of the single bevel's twisting action.

Just want to make sure everyone understands how single bevels twists as it encounters resistance.

Randy VanderVeen
HuntFullTime.com

Booner

So what about trocar tips and the crushing or busting of bone,,,,,less drag or more than a single bevel, double bevel, in everyones opinion....remember these are opinions and everyone is entitled to their own...We are getting into shaky territory and one of the most diverse in broadhead discussion. I really want to keep this one going lets see how well you folks can discuss..haha....if you come to an impasse, just agree to disagree. State your point's with purpose and courtesy all in one. If I see it getting to a point where it is no longer a discussion I will shut it down. ..... Let the topic begin.

Hunt Full Time

Booner,

The superior penetrating ability of single bevels is not an opinion. It's the law of physics. I know the report on single bevel heads is long, but it's worth reading, especially for a broadhead forum like this. It eliminates a lot of false assumptions.

If you take a knife with a single bevel blade, and you try to slice thru a block of cheese to make a nice even slice, it won't work. Because as you start to push thru the cheese, the blade wants to walk away from the side with the beveled edge. That's why kitchen knives have a double bevel.

It's also why a wood carver uses a chisel with a single bevel. It tends to want to go deeper into the wood which makes the carver's job easier.
That's also what causes a single bevel head to twist as it goes thru flesh, meat, bone, etc. It plows a path for the arrow shaft to go thru with little drag on it.

Oh yeah, almost forgot. It's easier to get a sharper edge on a single bevel and still not have it curl over when it encounters bone like a double bevel.
The edge is more durable when you only have to grind one side.

Another advantage of the Samuria head is the steel used. It has a Rockwell hardness rating of 58. This makes it extremely difficult for the average guy to sharpen these himself. But it takes a lot to dull these things. They come scary sharp out the box.

I believe the hardness rating of a steel G5 head is about 45. Still not bad. A lot of heads out there barely reach a 40 rating. Makes you think twice about shooting an average hardness double bevel head with thin blades.

Arrowds

In review of our studies...an arrow/broadhead...which is assisted in flight to maintain a semblance of repeatable accuracy at velocity via fletchings are rotating at a very high RPM. Upon striking an animal..this rotational momentum does experience lateral resistance and begin rapid deceleration, however they do continue to rotate at a much less RPM during transition thru animals due to laws of physics...rotational momentum... until that point of transitional depth coupled with the density of the object (rotational resistance) overcomes the value of rotational momentum. This can easily be seen when slowly pulling an arrow out of a foam target for example...rotational cut has occurred. Same effect on even a less dense subject than foam such as an animals differing densities discounting bone. There is also another aspect of bone itself to consider...at what moment of depth of penetration whether trocar type tip, cut to the tip two blade single/double bevel, etc...at what point during the transition of such bone does the bone actually fracture? This again has statistical probability to consider. The assumption in your statement is that the only factor is the single bevel to cause such efficiency in fracturing...yet we see in testing all replaceable bladed with a trocar style tip such fracturing occurs at a point typically with replaceable bladed designs before the blades engage the bone....it is then a matter of displacement of KE/Momentum to impedance of penetration/further shattering of bone once the blades do engage the bone. Meaning a two blade design has the ability to focus more energy on a smaller surface area from tip thru full width of cut...two blades...where and why other broadheads then lose KE/Momentum at an exponential pace is due to engagement of three or four blades to displace energy over a wider surface area...This is where the critical "Wedge Width" of the head defines overall efficiency to accomplish continued penetration/fracturing of the bone. The very same simple fact our Guillotine can easily decapitate a turkey's head when hit in the neck in about 300 milliseconds....yet when hit in the body, the four inches of cutting width displace energy over a four bladed wide area and the arrow simply bounces off the bird with no harm done to the bird.
I appreciate the fact you mention Laws of Physics...from a mathematical standpoint...can you describe what actual percentage of influence such a feature as single vs double has in relation to all the other larger variables which determine the outcome of depth of penetration? Meaning...given 100 shots thru big game animals in a true hunting situation....what percentage of impact does that specific attribute really contribute? The probability most likely is much less than .1%. Statistical probability simply must be considered and cannot be simply ignored. It was what I was attempting to relay in the example of how often a person experiences a "Robin Hood"....To define enhancing consistently the overall outcome when the statistical probability such "blade/rotational alignment/specific point of impact on the bone in question"...etc..when all this occurs....Then and only then may such a wedge shape to the grind angle add a small percentage of efficiency in the use of rotational KE/Momentum to aid in a deeper penetration in comparison to double bevel type. You see...I do agree with you at that point. However, the reality is....there are so many and much larger overall influencing factors occuring which determine final overall depth of penetration whether bone is struck so perfectly or not. Length to width ratio of head, overall surface area displacement at impact, overall thickness of blade/blades, angle of broadhead at impact with bone, spine of arrow, etc. Managing momentum/KE efficiently, effectively is the key to enhancing penetration. Reduction of surface area aids in focusing more energy on a smaller surface area...The same as you would use a magnifying glass and the sun....you simply allow the sun to shine thru it onto paper...it produces a big bright spot...you then adjust the focus...and obtain a very small focused spot....the paper then catches on fire quickly. Energy...when focused...amplifies greatly the outcome of the moment. Exactly the same management of energy based upon broadhead design during penetration of an animal occurs...just not so easily seen.
Statistical probability...laws of physics....these are merely the facts expanded upon a bit and I'm looking forward to your thoughts.

Zwartkop

that was the best explanation/ information I've ever heard or read about b/hs!

Very very well spoken!

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Mule426

This is an awesome thread. I am a student to the idea of single bevel and have relly enjoyed the conversation so far. I hope it continues in a way that will allow all of us to learn from it.

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Booner

Hunt full time......I agree with you...haha. I have read the report numerous times... I think it is definitely physics...no doubt. I also believe the physics of several other studies done by various companies. I wasn't saying the report was an opinion...I was asking everyone there opinion on whether or not they thought a trocar tip head caused the arrow to drag more or less than a single bevel or double bevel head. I have even read Dr. Ashby's latest report.