I got some Zwickey Deltas the other day and decided to single bevel a couple of them. At first, I was afraid I'd lose a lot of grains, but as it turns out, the 135 grain Deltas come about 10 grains heavy, I suppose to allow for sharpening.
Anyway, I flattened the edge down to the start of the bevel and filed in a new single bevel (left bevel). The triple layer stuff at the front still has a bit of a double bevel, but what the heck. I took one out and shot it into my 3d deer, just to see how they would fly...darts! Then as I was pulling it back out, it felt like it was rotating...hmmm. I shot one into a thinner part of the target that hadn't been hit before. The head had rotated about 1/4 turn on its way through maybe 5" of foam deer. It seems to me, after shooting a few more times, the arrow rotates about 1/4 to 1/2 turn depending on the density of the foam and the thickness.
Not that I doubted Dr. Ashby, but it's pretty cool to see it first hand. I know this was foam, but I don't see any reason to doubt that they will do the same thing on real critters. Unfortunately you are going to have to wait until October or so for an update :rolleyes:
I LOVE it...another convert (maybe?)!!!! I am looking forward to your updates this fall.
I've worked over a number of Magnus I 2 blades, and yes I've found the same thing, they do indeed rotate. :thumbsup:
Now think how much more rotation you would get with a thicker head like a grizzly!!!!
This is a good example of how they rotate. Look real close and you can see where it stared and where it ended up. This was done by pushing on the nock.
http://i297.photobucket.com/albums/mm216/ranger500us/IMG_0621.jpg
How about the wider single bevels like the abowyer heads. Do they get more rotation than say a grizzly?
Yes they do because the surface area of the bevel is greater thus increasing the rotation factor...or so I was told by Dan at Abowyer a couple of weeks ago.
Actually there are a few characteristics that influence how much a single will rotate.
A 3:1 profile will rotate more than a shorter, wider design will, and as stated above, a thicker blade with a continuous wide bevel from tip to heel will rotate more than a head that is only thick up front. The other is sharpness. The head has to cut in order to rotate so the sharper it is, the less resistance to rotation from the cutting action.
Ron
Just like rotating the axe on impact with the log helps make an easier split. So too with the rotating BH.
I'm a believer in the thick stock, wide-beveled single bevels, but I have yet any critters to share the results of... Come on October... :archer:
QuoteOriginally posted by bm22:
Now think how much more rotation you would get with a thicker head like a grizzly!!!!
Grizzlies rotate the wrong way for me. I shoot left wing feathers. Since folks have been killing stuff quite well with Deltas since the 1930's without rotation. I think the added rotation I get with these will do me just fine. Even if they don't rotate as much, the cut is 1-3/8" wide...I like that idea.
I just can't make myself spend that much for broadheads to kill whitetails and turkeys. They can only get so dead. If I were going after something that might try to kill me back, I'd consider the high priced spread. :rolleyes:
You guys should make a new X-files movie :thumbsup:
BTW...since when isn't a sharp broadhead "reliable"?
QuoteOriginally posted by Dave2old:
I do care about the freedom the enjoy unrestricted and open discussion of the many and varied possibilies in life ... and in this case, in fast, humane death of the animals we hunt when the much-hallooed but tremendously unreliable "sharp broadheads and perfect arrow placement" fail us. Dave
I understand what you're saying. But respectfully, if my ability to put an arrow where it belongs was "tremendously unreliable," I'd personally restrict my shooting to foam animals instead of real ones.
Do you get similar rotation when shooting through soft, mostly liquid substances like a deer's vitals? Once past the skin and very thin muscle layer, does the rotation continue?. I honestly don't know, but vitals like the lungs, blood vessels, and other organs(except the heart) are largely soft tissue made up of largely of blood. I just doubt that at that point rotation will occur and if it occurs will it increase killing effect.
I learned long before the single bevel mystique was created that the spiral in my fletching made the broadhead (old-fashioned double bevel) rotate in the target because the arrow is spinning when it hits, regardless of the brand of broadhead. Shooting foot-thick styrofoam, when the broadhead exited the other side, I learned to rotate the shaft about a quarter turn to get the blades realigned with the hole for extracting the arrow from the target. If I pulled straight back the blades hung up because of the rotation.
Maybe the single-bevel rotates more, but I've never lost an animal due to lack of rotation. From the pure physics point of view, additional rotation increases friction through the application of lateral forces to the medium, which would theoretically act to reduce penetration. Unless you're shooting elephants, it probably doesn't matter. Not trying to start an argument, just sharing my experience from 45 years of bowhunting.
I personally can not see how the rotation could not be robbing energy from the arrow myself.Of course I guess it is a mute point for what most of us hunt anyway.Any extra penitration would have to be measued in dirt on the backside of whitetails. ;)
The day I have to worry about penitration on a deer will be the day I quit hunting them.I will stick to foam animals where shooting them in the wrong places does not hurt anything . jmho :D
They may not be your head of choice, but they do rotate.
Take a close look at the edge profile, then at a double bevel... all the presure is on one side forcing the blade to turn as it cuts. Go cut something.
I don't think anyone is saying they don't rotate...anyone that's cut something at home with a single bevel kitchen knife knows it is not easy to cut straight with it....
Not to take away anything from single bevels (I shoot Grizzlies), but every standard broadhead that I've shot also rotates 1/4 to 1/3 turn into foam just from the arrow's incoming rotation.
Rotating broadheads I`m sure will help. But what is the gain?Not wanting a fuss just asking.
A rotating head through the lungs is a dead deer. A non rotating snuffer through the lungs is a dead deer.A broadhead anywhere else is trouble regardless if it spins or not.
I place all my confidence in MY ability to hit them where it counts because rotate or not they gonna be dead. Kinda like Mr. Wren stated. When I cant crack one through the ribs its time to fish full time.
If you guys are confident in the rotating broadhead I`m happy for you because confidence is what its about.RC
Story: Had a deer at 18 yards few years back - beautiful shot new it was toast - like has been said I am confident in my abilities out to 25 yards 18 is no issue. At the shot the hit knocked the deer down to a point it was flopping on the ground - deer recovered got up and took off.
No worries good hit - never found the deer - I did find a bit of my arrow drove into the ground where it had fell. Well that deer was killed by another person during the rifle season (healthy and fat, no ill effects from arrow) BHd was in shoulder bone never penetrated.
I have had BHds get through shoulder blades as well. but that one has always stuck in my craw and made me want to stack as much chances in my favor as I can. Figure Ashby's tests are about as sound as they come.
Things go wrong moral of story no matter how good you are.
J
"From the pure physics point of view, additional rotation increases friction through the application of lateral forces to the medium, which would theoretically act to reduce penetration." Don Stokes
It's actually the other way around Don, it's the friction (force) from the forward moving BH acting upon the beveled portion, that causes the broadhead to rotate, NOT the rotation of the arrow from the fletching acting on the tissue causing lateral friction, thereby reducing penetration...make sense? Your statement is correct if the force to generate that rotation were from an outside source, but it's the BH spinning the arrow not the arrow spinning the BH. The arrow rotation from fletching DOES compliment the BH rotation (provided they are matched) but only acts initially and is secondary once the BH engages heavier tissues and bone. Ashby's provides a complete explanation of how this works.
Respectfully - Kris
"I personally can not see how the rotation could not be robbing energy from the arrow myself"
James Wrenn
Many parts to this answer James, but here's one that involves bone hits. As with all Ashby's work there is a ton of data on live/dead animals to support his work.
"Using arrows that are virtually identical, and at equal impact force, the consistency of outcomes is demonstrative that single-bevel broadheads are using less arrow force in breaching the bone, conserving force that can be applied to increasing penetration." Ashby 2007 page 5
"Rotating broadheads I`m sure will help. But what is the gain? Not wanting a fuss just asking.
A rotating head through the lungs is a dead deer. A non rotating snuffer through the lungs is a dead deer. A broadhead anywhere else is trouble regardless if it spins or not". RC
I agree with the first part above, but have this to offer regarding your last statement. Let's say you did happen to hit scapula, (which I know never happens to anyone reading this post)and you were able to get penetration thru that bone and into both lungs, would you opt for an arrow with that capability? I certainly would. This is a very realistic outcome with a single-beveled BH w/tanto tip, plus the other arrow recommendations Ashby offers. But if you always hit exactly where you want and you always have complete exit penetration on every size animal you hunt, then this probably doesn't pertain to you (not you personally RC, just a general statement). The solutions, or at least the insight to these questions (which get posted about every week here) on this topic can be found on Rob DiStefano's posts of Ashby's Lethality Studies.
I don't know how any bowhunter could not be interested in this information? If you don't accept what Ashby's reports say, than this is a mute point, and I respect that. I accept what he has to say, simply because he has an insurmountable amount of experience and data, that he has compiled objectively. No other source of information concerning subject approaches it. It's really about being honest with the outcome of every animal we hit, and analyzing it objectively, so we can apply that experience to the next time.
I try to read Ashby's stuff w/o a bias, as I too use(d) Snuffers, 2 & 4 blade Deltas, Ace, Zephyrs, Bear, Deadheads, Eskimos, Woodsmans, Magnus I & II, Ribtec, Eclipse, STOS, Hills, Grizzlies and recently, Abowyers for this fall. It's all fun and interesting; aren't we lucky we have so many choices? What do you think keeps us in this sport?
This was not all directed at you RC, I just continued with my opinion.
Kind Regards - Kris
Yeah, I use everyting too I might add. but even on my 3 blades now I use the EFOC principle from Asby's reports. People seem to pull just the single bevel stuff from his reports but there is obviously alot more to gain from his studies. I know I have killed my share with a bow and many different styles of heads (cept sengle bevel, will change that this year) - there is only one degree of dead and sharp is the true key, don't think anyone doubts that.
J
When considering bone hits, remember that Dr. Ashby was using very heavy bows and arrows. Don't expect to shoot through the scapula with a 45# bow with any arrow or head.
There's no doubt a good, sharp single bevel will do a great job, but when you cite studies you must also cite all of the critera that goes into it, and why it was done in the first place. And, don't throw the baby out with the bath water. Quality broadheads, regardless of blade design, will kill any game on the face of the Earth.
The problem with discussing them is there is always a few people who seem to deem everything else useless in light of this relatively new (but not really new) marvel. And then, they look down their very long noses at those who do not agree with their new found logic.
It is not the smartest person who would argue against using the venerable old style, double edged broadheads, that have been proven plenty effective over such an historic period. One might better spend that time learning to shoot better and fining-down their accuracy quotient.
QuoteOriginally posted by George D. Stout:
It is not the smartest person who would argue against using the venerable old style, double edged broadheads, that have been proven plenty effective over such an historic period. One might better spend that time learning to shoot better and fining-down their accuracy quotient.
Amen, George.
To that I would add, shoot what you can sharpen the best.
Don, maybe not 45#, but maybe? Please read if you will, pages 11 thru 19, as Ashby compares a 54# longbow using 'Extreme FOC arrows' and a 70# bow using 'Common Arrows' too many things to include here.
http://www.tradgang.com/ashby/2007update4.pdf
Absolutely George, you are correct! There are many criterions that go into this each and every condition (in this case, shooting an arrow through an animal for a lethal outcome). I cite a study only because these variables are addressed there for us to contemplate. So much is discussed about broadheads when they are only one part of the whole. I care not what choices you or anyone else makes regarding your setup, if I sound like I'm trying to convince someone of something, I apologize, I am not. It can be educational (good fun) though, to have an informed discussion with folks that have similar interest, hence, this forum.
Respectfully - Kris
Hi Kris. No harm, no foul. Most folks don't really try to convince others that they are boneheads for using conventional heads....only a few who have had an ephiphany. Fact is, there are so many good broadheads nowadays, that it is hard to make a bad choice. I won't speak about the mechanical things since I don't consider them broadheads. We are indeed fortunate to have guys like Dr. Ed doing such studies. It has much merit and is very helpful to those who expect to pursue the big fellers in Africa or Australia.
Hey George –
Thanks for your reply. I just re-read my own previous post and actually, I do care what fellow bowhunters use, because I care deeply about bowhunting and its future.
We have such passion for this sport; it's like anything you care deeply about, you defend and express beliefs based on your values, knowledge and experiences.
I read the same threads as you, and see the reaction when you hear "this works the best"! I don't think we intend to offend anyone. Often, writing doesn't convey the true tone of the message. I often hesitate to write or say anything. At the end of the day, we only have each other to ensure the future of our sport, I believe we are all on the same page!
This forum is an great venue to share and express our ideals.
All the best and Happy Fourth!
Sincerely - Kris
Hmmm. Another single/double bevel topic. Ton's of broadheads out there getting the job done. Pros and cons to all of them. Talked to someone who killed a deer using a broadhead made from a soda can. Probably not the best, but it got the job done. Don't think anyone can argue any longer that single bevels go through bone better. Don't think anyone can argue that more blade area has more area for cutting. Are the differences in cutting area worth the decreased penetration of extra blades? Is the increased penetration of single bevel in bone more important in most circumstances? Must you always use the most efficient method and, if so, why aren't we using guns? Interesting questions that have to be answered by the individual and tailored to what bow is being shot, the strength of the bow, and the persons desires. I hope everyone enjoys and has confidence in there setup. I don't think any of you are unethical for your choice. I have some single bevel, two blade, and 3 blade, and use them all. Incidentally, anytime there is rotation of the arrow it robs the arrow of energy. I just think in the case of single blades it is probably insignificant. The loss of energy in terms of in-flight stability and 'opening up' bone is probably worthwhile. Good luck and happy 4th.