Eclipse Broadhead

[OH at work]

Thanks Ed,   there is a lot of good insight for the head on this thread!!!

Joe

[Dr. Ed Ashby]

Thanks Darke, I try my very best to consider all the possibilities, and test all I can figure out how to.

I think you'll like the Eclipse. They have impressed me enough that they are now on my "I'll us it' short-list of broadheads ... and, since I'm sort of a 'zero tolerance' guy when it comes to my hunting arrows, that's a pretty short list! Just be sure to alter the tip a bit so it doesn't curl. The Eclipse's blade is a bit tougher than the Zwickey. Not at all a bad place to be!

Ed

[Joseph]

I have shot 2 animals now with 4 blade Eclipse broadheads.  One was an approximately 175 pound ferel boar in Australia and the other was a young bison bull that was about 1100 pounds.  I got excellent penetration on both shots and on both occasions the bleeder blades sheared off when bone was hit and the arrows continued on their way deep into or through the critters vitals.  Joseph

[**DONOTDELETE**]

So, what is a "tanto tip" Dr. Ashby? Is that where you would file the tip flat for maybe an 1/8" and then sharpen it?

[Dr. Ed Ashby]

David,

No, the Tanto tip is neither a flat tip nor a chisel tip. Here's the history and description.

"Tanto Tip" is a term I coined over a quarter century ago, during the original Natal Study. For data purposes I needed to name each BH's tip profile. There just wasn't a name for the tip design on the Grizzly. It's shape reminded me of two Tanto knives placed back to back. That's how the name came about. As I used the term in my study reports, the name just took hold, probably for the same reason; it describes the tip's shape fairly well and there just wasn't another name floating around.

At any rate, if you're familiar with the tip shape of a Tanto knife, you should get the idea of the shape. If not, look on the Cold Steel web site and see what a Tanto knife's tip looks like, and just picture two of them placed back to back.

"Tanto" is a profile. That means you can have a large Tanto tip or a small Tanto tip. You can also have a cut-on-contact Tanto (like I use) or a non-cut-on-contact Tanto (like the factory Grizzly's tip).

Hope that answers your question,

Ed

[**DONOTDELETE**]

Thank you for the explanation Doctor. I think I understand it. So is this chisel angle put on just one side of the broadhead?

[Joe Subler]

Snag, if you go to Dr. Ashby's reports in the forum choose the 2005 report and click on page 1.  It has a picture there of an Eclipse with a tanto point.

Joe

[Dr. Ed Ashby]

David,

An edge  bevel can be applied to a Tanto profile COI BH’s tip as either: (1) a single bevel or (2) a double bevel. If you use a single bevel as the Tanto tip’s edge finish, it can be applied on either: (1) the same side as the edge bevel (for that half of the blade) or (2) on the opposite side.

I've been experimenting with all the above COI Tanto sharpening configurations, trying to see if I can isolate any performance difference. Some of the results are SUGGESTIVE that a single bevel placed OPPOSITE the corresponding edge bevel (for that half of the BH's blade) MAY do better in splitting bone - and I can’t even CONJECTURE an explanation of "Why" yet. I need more data to examine. It's just too early in the testing for me to draw any firm conclusion. Whenever I KNOW with a high degree of certainty IF there is a difference (and which works best, if there IS a difference), I'll be sure it's in a Study Update.

Ed

[strick9]

Now that my friends, is good meat on the table information, Thanks

[DarkeGreen]

SUGGESTIVE that a single bevel placed OPPOSITE the corresponding edge bevel (for that half of the BH's blade) MAY do better in splitting bone - and I can’t even CONJECTURE an explanation of "Why"

My guess is that when it is pushed thru the bone one edge acts with the other to twist the blade prying apart the bone. If the blade has a single bevel, both on the same side you only get a slight lifting action with friction applied, double bevel provide no lifting or twisting and would perform poorly.

If the single opposing bevel is configured to match the direction of arrow spin the force applied would be greater helping to lift, twist, and pry the bone. once the bone is cracked in this manner half the blade should be free of any contact allowing it to penetrate much easier.

Just a guess, but I think you could reproduce this somewhat with a couple chisels and different types of wood.

Animals bones have different amounts of calcium causing various amount of brittleness. What is true for one anamial may not be true on the next or it may be true but to a lesser degree. When searching for bones that resemble human bones you have to use one paticular type of goat if you want an exact match to study bone fracture and their affects on projectiles and wounds.

What I don't know is what matches the bone content of a whitetail deer or that of a buffalo. I do know that goats are not even the same from one type to the next. Some have less calcium are more elastic and therefore do not fractue as well as those with a higher calcium content.

[Dr. Ed Ashby]

Darke, that is pretty much my hypothesis also; the brief 'twist' one direction followed by a forceful reversal in the opposing direction is helping the tip achieve 'purchase' on the bone surface, especially with impact on a non-flat bone surface (which is nearly EVERY bone impact, since the bone surfaces are a collection of arches, domes and radius curves, often curving in more than one direction simultaneously).

However, it's still purely hypothesis at this point. I keep trying to see minute surface detail to ascertain if I can actually see any difference. Unfortunately, there's often too much damage to the bone from the main blade's passage to see anything that helps me much.

Like most things, it will probably come down to a statistical analysis of with gives the most favorable outcome with the highest frequency.

Thanks for the input.  Insightful, as always, and I really appreciate it.

Ed

[Ron Vought]

I have been using Eclipse Broadheads from the very beginning. All I can say is great Broadhead! The metal is very hard so when you start an edge you will need to put alot of pressure on the broadhead to start the edge. If you don't see metal being removed then you are basically doing nothing to start the edge. Once the edge is started lighten up with sharpening. The Eclipse broadhead will get razor sharp. They stay sharp once you get them sharpened. I personally like the 145 grain Edclipse Broadhead.

Ron

[aromakr]

I find it difficult to believe that a spinning arrow from however heavy a bow or arrow would have enough tork to cause a bone to split, regardless of the bevel on the broadhead, espically in a very large animal, say in excess of 800#
Dr. do you see signs of a spiral cut in the bones themselves, indicating this?
Bob

[Dr. Ed Ashby]

Bob, check out the pictures of the single-bevel spiral cuts and bone splits in the Updates. They show clearly, even with BH's as narrow as 11/16". Since some more (different) single bevel BH’s are on the test agenda for this year, I’ll probably be adding more bone-split pictures into the next update(s).

I can’t remember the thread name, but I also posted a picture of a spectacular single-bevel bone split on the scapula of a large wildebeest bull … with large bone fragments also blow into the surrounding tissues. Now, such a violent bone split is not exactly the norm, but it’s also not exceptionally uncommon. I’ll try to post it again here (I’m not too practiced at posting photos yet). Oh, the arrow had an exit wound too, almost a pass-through,. The arrow fell out on the first jump. He dropped in just a few yards.

 


Laboratory test and resulting theories are great starting place, but real-world outcomes from large test samples are definitive. Heavy bone splits are the norm with single bevels and, thus far, their occurrence is totally absent from every double bevel hit.

I also have copies of the pictures from Doug Chase's two BIG buffalo bulls from last year, and permission to use them, but won't use them yet because it's my understanding he plans on writing an article and using the photos in it. He deserves first chance to put them out there. Anyway, Doug used a left single bevel STOS, on arrows setup along the Study guidelines. He hits ribs on both shots, and got really good photos of the resulting MASSIVE bone splits (also with large bone fragments blown away). He also achieved exit wounds on both bulls, with about a foot of arrow protruding out. He did that with a 66# DAS recurve. (There’s more details on Doug’s buffalo hunt in several of the threads over on the Dangerous Game forum.)

The data simply leaves no doubt at all. The rotation shows on the bones, and the bone splits are a consistent feature. A single-bevel BH's outcome penetration is uniformly higher when single vs. double bevel is tested ON OTHERWISE IDENTICAL broad heads and arrow setups - for every single blade BH’s so tested, to date. The only single blade ‘profile’ left to test this way are the pronounced concave blades, such as the Sharks. That’s on this year’s ‘scheduled test’.

Ed

[outbackbowhunter]

Dr Ed,
      Have  you seen any advantage in single bevel styles regards arrow spin in flight.

I have had a few people mention  to me that single bevel styles seem to shoot tighter groups for them in practice, compared to a double beveled version of the same broadhead model.

I enjoy reading your research on what happens on broadhead arrival/impact,...but they have to be delivered accurately first, before the work begins.

Do you have any data on broadhead design configurations that enhance accuracy.

                            Good hunting,
                                         Woody

[Dr. Ed Ashby]

Hello Woody,

You just caught me on my final TradGang check before heading for the plane back to Oz! I depart here in a hour.

I don't have the answer to that one! That's probably because I can't shoot well enough to be able to tell if there's a difference! It's an interesting question though.

Are you hearing this back from customers? Are they reporting it with all the different BH profiles?

I think I might know a few folks who can check that out though. When I get back to Oz, I'll email a few folks and see if I can interest them in doing a bit of testing ... by both a top target shooter and from a shooting machine.

That should be easy to test. As with the bevel penetration testing, a side by side 'identical setup' test with matching BH's of both single and double bevel configuration (with a series of different types of BH profile; long-narrow and short-wide) should give a clue ... if not a clear answer.

Thanks, Woody. An interesting aspect. I'll see what I can do to find out for you.

Ed

[outbackbowhunter]

Ed,
   Its the single bevel Supreme model that has been mentioned to me.

The guys that have noticed this are sighted compound shooters, practiceing at 40 or more metres, but if there is something in this I cant see why it wouldnt be a benifit with trad gear also.

I'm always interested in anything that works, and would really appreciate an independant test to see if there is something to it.

When you arrive in Oz, email me if you would like some samples to play with.

OH at work, my apologies for hijacking your thread.

[DarkeGreen]

I just read one of the comments about twisting and wanted to note something.

My theory is the single bevel on oposing sides is the cause of the "twisting not the rotation of the arrow. The rotation of the arrow would either be added to or subtracted from the total effort based on the spin direction.

Draw a line on a piece of paper. On one end draw another line angled up and 25 deg and on the other end draw a line angled down 25 degs. Now think about a chisel. With a single bevel. When you drive it in the wood the flat side goes straight in the wood while the angle or bevel causes the wood to lift up and away from the blade.

With a broadhead that has two oposing angles the lifting action is added together which causes the center of the "tool" to rotate. It would be darn near impossible to get any penetration without this action. The thing that in part determines how the bone breaks is how brittle it is.

When you have a double grind on each edge, as the blade penetrates it remains centered by each edge compressing toward the center of the blade. You have 4 edges or bevels (two per side)that counter act any twisting motion you would have had. another words it travels in a straight line as it penetrates.

[OH at work]

Outback, no apology needed.  Always interested in new things regarding of which thread it is!!!

Joe

[ux monster]

I dont know about eclipse,i have never used them,but i am a huge fan of journeymans.They were made in erin ontario not far from where i live so i bought what i thought would be a lifetime supply just before they sold to eclipse
but my supply is running out.I have enough journeymans to last a few more years than i guess ill be forced to go with eclipse,one fantastic head.