Bowhuntr64
WKR
Some of you may remember Bishop Archery going on AT recently and touting their new broadheads: The "Dicing Drill" and the "Scientific Method." Unique names. You can do a search there and find those threads with some pretty amazing and somewhat confusing (at least to me) claims.
They had a random drawing and, low and behold, I won So I was sent a single Dicing Drill, in 125 grains. With my elk season sadly passed, I had a bit of time to run some tests on this head. I took a lot of video footage, which I will be editing and releasing as soon as I get a chance. In the meantime, I will share some impressions.
First, my overall observations. The head is a single bevel, two blade head. It has a cutting diameter of 1 1/8" and is .72" thick. It is sharpened at a 40 degree bevel on all sides, including the back edge and the tip. It has a very stout tanto tip that may look blunt, but is anything but. It is created by two single bevels converging, at a different angle than the main blade angle. It resembles a Helix in design, but is much stouter.
Beyond the thickness and the geometry, is the fact that this head is machined out of a sold piece of S7 Tool Steel. This steel has unique properties, not the least of which is its ability to be treated to a Rockwell Hardness of 58, without becoming brittle, as most steels would at that hardness. This is especially significant because it is a single bevel head. As you may know, single bevel heads rotate upon being forced through a medium. This rotation helps in three primary ways, as Dr Ashby and others have demonstrated: (1) It aids in bone splitting. Rather than just penetrating directly into a bone, it penetrates and rotates, prying the bone apart. (2) It twists hide, organs, and tissue around itself and thus often cuts more than a double bevel head would. You can compare it to a fork cutting spaghetti vs a fork twisting into spaghetti and then cutting it. You will cut more spaghetti with the twisting taking place. (3) It creates a circular wound channel that is more difficult to seal up than a single plane wound channel, thus aiding in blood loss.
But the inherent weakness of single bevel heads is there is so much pressure on the leading edge of the of the blade, that they are prone to chip or break. And there can be so much twisting pressure on the ferrule, they can shear off there.
This is where the S7 tool steel is supposed to make a huge difference. It is so hard and so durable and so resistant to chip or shear, that it eliminates the inherent weaknesses of the single bevel head. This, combined with the thickness of the Bishop heads, and the geometry which is supposedly superior to Ashby's designs, allows all the benefits of a true single bevel head with fewer of the weaknesses.
Now, on to my tests. I shot this one head with a .340 Axis arrow, with a total weight of 485 grains, through my Hoyt CS 30 bow at 73# and a 26.5" draw length. I shot it about 20 times with NO resharpening in between.
I shot it through cardboard and a pumpkin, to test the rotation. And I shot it through wood, tile, bone, meat, and steel to test the edge retention. In all, I shot it through the following:
120 layers of cardboard
1 pumpkin
6" of wood (plywood and boards)
1 large hog shoulder roast
1 large rib with meat, from a 750 lb boar
110 layers of laminate tile
10x through .22 gauge steel plate
10x into a Rhinehart 18:1
After all that, and NO resharpening in between, the head still spins true and show NO signs of wear. I can still shave my thumbnail with it. It doesn't shave my nail quite as easily as it did when I first shot it, but it definitely still shaves it.
As for the wound channel, it was impressive. The holes in the tiles toward the back of the stack were much larger than those of a three blade, 1 1/4" head that I shot next to it. The holes in the back of a 1/2" plywood were only slightly smaller than those of a three blade 1 1/4" head. The hole through the "innards" of the pumpkin were circular and not a slit, due to the rotating action. It was extremely difficult to get out of my Rhinehart, due to the rotation--I mean, really difficult. It typically rotated an extra 90 degrees after the initial penetration into the Rhinehart, which was always after it had already penetrated through whatever was in front of the Rhinehart.
Here are the pics of the head AFTER all that penetrating.
I did not test the long distance flight of the head yet. Honestly, by it's construction and geometry, I am sure it will fly well out of a tuned bow. But I will test it more in that arena in the future.
Note, this is NOT an inexpensive head. They are roughly $50 per head. Not for three, but per head. However, you are certainly getting what you pay for. If you don't lose it, I bet you would be killing critters with it for the rest of your life. It's up to you whether it's in your budget or not. I got this one free
I am planning a Cape Buffalo hunt in Mozambique in the future, I have no doubt, this head, or probably their heavier Scientific Method version, will be on the tip of my arrow at that time.
The video of my testing will be coming out soon.
They had a random drawing and, low and behold, I won So I was sent a single Dicing Drill, in 125 grains. With my elk season sadly passed, I had a bit of time to run some tests on this head. I took a lot of video footage, which I will be editing and releasing as soon as I get a chance. In the meantime, I will share some impressions.
First, my overall observations. The head is a single bevel, two blade head. It has a cutting diameter of 1 1/8" and is .72" thick. It is sharpened at a 40 degree bevel on all sides, including the back edge and the tip. It has a very stout tanto tip that may look blunt, but is anything but. It is created by two single bevels converging, at a different angle than the main blade angle. It resembles a Helix in design, but is much stouter.
Beyond the thickness and the geometry, is the fact that this head is machined out of a sold piece of S7 Tool Steel. This steel has unique properties, not the least of which is its ability to be treated to a Rockwell Hardness of 58, without becoming brittle, as most steels would at that hardness. This is especially significant because it is a single bevel head. As you may know, single bevel heads rotate upon being forced through a medium. This rotation helps in three primary ways, as Dr Ashby and others have demonstrated: (1) It aids in bone splitting. Rather than just penetrating directly into a bone, it penetrates and rotates, prying the bone apart. (2) It twists hide, organs, and tissue around itself and thus often cuts more than a double bevel head would. You can compare it to a fork cutting spaghetti vs a fork twisting into spaghetti and then cutting it. You will cut more spaghetti with the twisting taking place. (3) It creates a circular wound channel that is more difficult to seal up than a single plane wound channel, thus aiding in blood loss.
But the inherent weakness of single bevel heads is there is so much pressure on the leading edge of the of the blade, that they are prone to chip or break. And there can be so much twisting pressure on the ferrule, they can shear off there.
This is where the S7 tool steel is supposed to make a huge difference. It is so hard and so durable and so resistant to chip or shear, that it eliminates the inherent weaknesses of the single bevel head. This, combined with the thickness of the Bishop heads, and the geometry which is supposedly superior to Ashby's designs, allows all the benefits of a true single bevel head with fewer of the weaknesses.
Now, on to my tests. I shot this one head with a .340 Axis arrow, with a total weight of 485 grains, through my Hoyt CS 30 bow at 73# and a 26.5" draw length. I shot it about 20 times with NO resharpening in between.
I shot it through cardboard and a pumpkin, to test the rotation. And I shot it through wood, tile, bone, meat, and steel to test the edge retention. In all, I shot it through the following:
120 layers of cardboard
1 pumpkin
6" of wood (plywood and boards)
1 large hog shoulder roast
1 large rib with meat, from a 750 lb boar
110 layers of laminate tile
10x through .22 gauge steel plate
10x into a Rhinehart 18:1
After all that, and NO resharpening in between, the head still spins true and show NO signs of wear. I can still shave my thumbnail with it. It doesn't shave my nail quite as easily as it did when I first shot it, but it definitely still shaves it.
As for the wound channel, it was impressive. The holes in the tiles toward the back of the stack were much larger than those of a three blade, 1 1/4" head that I shot next to it. The holes in the back of a 1/2" plywood were only slightly smaller than those of a three blade 1 1/4" head. The hole through the "innards" of the pumpkin were circular and not a slit, due to the rotating action. It was extremely difficult to get out of my Rhinehart, due to the rotation--I mean, really difficult. It typically rotated an extra 90 degrees after the initial penetration into the Rhinehart, which was always after it had already penetrated through whatever was in front of the Rhinehart.
Here are the pics of the head AFTER all that penetrating.
I did not test the long distance flight of the head yet. Honestly, by it's construction and geometry, I am sure it will fly well out of a tuned bow. But I will test it more in that arena in the future.
Note, this is NOT an inexpensive head. They are roughly $50 per head. Not for three, but per head. However, you are certainly getting what you pay for. If you don't lose it, I bet you would be killing critters with it for the rest of your life. It's up to you whether it's in your budget or not. I got this one free
I am planning a Cape Buffalo hunt in Mozambique in the future, I have no doubt, this head, or probably their heavier Scientific Method version, will be on the tip of my arrow at that time.
The video of my testing will be coming out soon.
I kind of made it half informational about Single Bevel Broadheads in general and half about the test of the Dicing Drill itself.
