Bolstermanic wrote:OK, maybe "hate" is too strong a word, but JD is onto something here ... I think he's right, there appears to be a trend toward flat grinds. Yes, many of us like various grinds, but that's beside the point. Particularly in light of Doc Snub's tests showing the efficacy of hollow grind, why are we seeing new SD designs in flat? Are SD designers not testing? Or is the data contradictory? Bigger question, is flat grind a fad (a temporary variation fueled by social consensus) or an evolution (a genuine improvement and the way of the future)?
Just because the flat grind in the ChinookIII didn't produce the results I spected to see doesn't mean that flat grinds aren't good for self-defense just the contrary...take a look at the results of the Yojimbo and Ronin, they just about out cut anything on the market today for their size...and my major choices for a SD knife....I think the results of the Chinook III in my tests reflects the fact that the blade design has a lot of belly...which is notorious for long but not deep cutting abilities....In the case of the Chinook II Hollow Grind Knife...the spine is thicker the knife is heavier and I think those factors came into play as to the results. There is a real reason SD knives are being made with a flat grind in increasing numbers, that real reason is that it works well for SD.....Doc :D There is an old post by Joe Talmadge and IIRC he explains it a little better than I...I'll see if I can find it and post it here.
Quoted from a Joe Talmadge post "I do think there are materials where a big belly will slice better, but I'm not sure how much they apply to defensive use. Imagine very hard ballistic nylon: The straight edge would penetrate deeply and quickly, then either get hung up (if you can't power through) or slide back out -- straight edge is mostly push-cut with a little slash. A knife with a belly would open a shallow zipper for a longer distance -- belly gets you a lot more slash with your pushcut."
Michael Janich's take on this also from an old post.... "First of all, thanks to Dr. Snubnose for his testing efforts and for sharing his results. His tests are great empirical stuff that is much more valuable than the speculation and conjecture that often pollutes Internet forums.
My early understanding of edge geometry was based on what I had read in books and magazines. Most of that stated that a good fighting knife had to have a lot of belly to cut effectively, the point had to be close to the centerline of the knife for energy transfer during a thrust, and straight edges tended to tear rather than cut. I believed all that and accepted it for a long time (If you look at my MOD Tempest design, you'll see that it's got considerable belly to the edge).
When Mike Snody asked me to design the "ultimate neck knife" (his words, not mine), I decided to start from scratch and do the empirical testing needed to determine the best blade shape for a small, concealable knife. I spent a long time (not to mention a lot of pork roasts, old jeans, floating pool noodles, water-soaked grass mats, and even leather jackets) doing actual live blade cutting. Some of the cuts were snap cuts -- which require good distance appreciation and accuracy -- and some of them were the locked-wrist follow-through cuts I prefer.
What I learned was that the arc of motion of the cutting edge, as well as the point of impact on the length of the edge, are huge determining factors in cutting performance. The traditional thought process -- lots of belly and snap cuts -- works very well, PROVIDED YOUR DISTANCE IS CORRECT AND YOUR EDGE STRIKES THE TARGET WITH THE BELLY. If it does, the belly creates a shearing cut until it reaches the tip of the knife.
If you hit short with a snap cut, you either get a shallow chopping cut or you actually push the material away from the edge and get a dent rather than a cut. If you hit short with a locked-wrist, follow-through cut, you get a chopping blow that doesn't do much with a light blade. If you hit at too long a range, the arc of the belly of the edge and the arc of travel of your arm typically run parallel and you get a shallow, superficial cut.
With a straight edge like the Ronin or Yojimbo, it's a different story. If you hit short on a snap cut, NO MATTER WHERE YOU HIT ON THE STRAIGHT EDGE, THE ENERGY TRANSFER TO THE TARGET IS THE SAME. If you hit with the tip (as Doc probably did in his tests), the energy transfer buries the tip deeply, cutting like a hawkbill, but without the danger of snagging. THE FACT THAT THE CUTTING EDGE LEADS THE CUT, THE FULL FLAT GRIND PARTS THE MATERIAL WITH MINIMAL DRAG, AND THAT THERE IS VERY LITTLE BLADE BEHIND THE LEADING PORTION OF THE BLADE EDGE TO CREATE DRAG CREATES THE SENSATION OF EFFORTLESS CUTTING (which Doc also referred to). MOST IMPORTANTLY, NO MATTER WHERE YOU HIT WITH THE EDGE, YOU GET A FULL TRANSFER OF ENERGY INTO THE TARGET, THE BLADE CUTS ALL THE WAY TO THE TIP, AND THE TIP CREATES A LONGER CUTTING RADIUS THAN A BLADE WITH BELLY.
If you use a locked-wrist follow-through cut, the results are even more dramatic because you start at the heel of the blade and draw the full length of the edge through the cut in an incredibly effective slicing action.
The effectiveness of the straight edge is not a new thing to edged weapons. The scramasax was basically a straight edge (or close to it), as was the Filipino kampilan. Several years ago, James Keating, still one of the preeminent edged-weapons tacticians of modern times, designed a knife called the "Straight Shot" (if memory serves me correctly) that also featured a long, straight primary cutting edge. For all the Bowie fans out there, a back cut with a straight false edge is also the functional equivalent of a cut with the primary edge of a wharncliffe blade. As such, I didn't invent this stuff, I simply took the time to quantify and understand it.
A lot of folks have taken shots at the Yojimbo and Ronin as ugly knives with supposedly fragile tips. However, once most people actually see one cut -- or better yet, do some cutting themselves -- they usually change their minds pretty quickly.
For the record, when Mike Snody first saw the Ronin (which I designed in response to his request for the ultimate neck knife), he didn't want to make it. To his credit, though, before dismissing it, he ground one and actually started cutting with it. Shortly thereafter, he called me on the phone and described the cutting performance of the knife in one word: evil. (Actually, it was two words: f*&$ing evil.) Later, while reaching for something in his shop, a partially finished Ronin blade "bit" him. He said he'd never been cut so badly, so easily. He also said that working on the custom Ronins and the Yojimbo prototype changed his thoughts on knifemaking forever. From the looks of the Benchmade Gravitator (which he was both ethical and kind enough to show me in the prototype stage), I'd say he was telling the truth...
I hope this helps shed some light on the reason I'm a wharncliffe fan. I like stuff that works."
Stay safe,
__________________
mike j
"Always Judge a man by the way he treats someone who could be of no possible use to him"
*Custom Avatar with the Help of Daywalker*
:D
