Friction Forging® is a localized forging process using high temperatures and high loads to deform and rapidly quench the steel in the zone that will eventually become the knife edge. Friction Forging® uses a specially designed tool made from Polycrystalline Cubic Boron Nitride (PCBN), a material second only to diamond in hardness. During forging, the PCBN tool penetrates the blade while rotating, which creates frictional heating and plasticizes (not melts) the steel. When the tool is fully engaged, it moves along the eventual blade edge, creating dynamic microstructure shearing and high forging pressures that produce excellent blade microstructures. The tool's rotation speed, X & Y axis travel speed, Z loads, and blade temperatures are all computer controlled and monitored to insure consistency and repeatability for each blade.

The blade edge is brought above the transformation temperature by the rotating PCBN tool. As the tool moves, the knife-edge is continuously forged. The combination of thousands of pounds of downward forging force, tool rotation, and temperatures slightly above the transformation temperature produce dramatic reductions in austenite grain size. The grains are in effect torn apart and reduced in size by the combination of very high pressure and heat. Transmission Electron Micrographs (TEM) indicates that the grain size is reduced from 5-15 microns in typical heat-treated D2 knife steel down to 0.5 microns, a superfine "nanograin" size.

First, let's define what a "better" blade is. A high performance "Super" blade has several differentiating characteristics:

1. The blade edge is 5-8 Rc points higher than the "best" heat-treated D2 blade steel.
2. The edge zone Martensite grain structures are 10x FINER than are those in conventionally "best" heat-treated D2 blade steel.
3. The blade STAYS SHARP SIGNIFICANTLY LONGER than other blades.
4. The edge is CORROSION PROOF and eliminates chemical etch dulling.
5. The blade is TOUGH and can withstand transverse loads effectively-that is, you can flex the blade without the blade breaking or bending.

Why does one blade stay sharp longer than another? Materials that are harder and finer grained are proven to resist deformation due to abrasion better than a softer material. Therefore harder steels resist edge deformation (dulling) better than a softer blade. So this is one very key element in the equation, a harder blade will stay sharp longer than will a softer one. How do we measure hardness? Metallurgists and knife manufacturers typically use a couple of scales, one is called the Vickers scale and the other is known as the Rockwell "C" scale. Most knife users and manufacturers are more familiar with Rockwell so we will report our hardness values referencing the Rockwell C scale.

First, let's set some ground rules to insure a fair comparison. A "fair comparison" mandates the blade shape must be EXACTLY the same between the blades being tested. This does not just apply to the overall shape; it means the cross-section geometry must be IDENTICAL from the cutting edge all the way to the spine and from one end of the test area to the other. We tested the Friction Forged® blades against blades of 13 different materials. All test blades were identical in overall and cross section edge geometry and thus the only difference was blade material-not shape.

Materials tested against the Friction Forged D2 were 440C stainless steel, 154CM stainless steel, 5160 steel, D2 tool steel, AISI A1 and AISI 01 steel, 52100 steel, BG42, CPMS30V stainless steel, CPMS90V stainless steel, AUS8A stainless steel, 1095 steel and Talonite. All these materials were heat-treated, tempered and cryogenically treated with resulting RHc values between 58 and 61 depending on the steel (with the exception of Talonite).

Next, the comparisons must be made on the same day, ideally at the same time, using the same test media. Finally, the tests must be made "hands-off" to eliminate the human factor. Tests of cutting ping-pong balls, bottles of water, free-hanging rope, slabs of hanging meat, etc. are interesting and certainly illustrates one persons ability over another-but does it test one knife against another? Somewhat, but not very well. Those tests are subjective, biased, and not objective. This mandates we rely on precision computer-controlled and mechanical equipment to perform tests.

The following test equipment descriptions explain the methods we use to determine sharpness, edge retention and longevity, and edge toughness.

1. CATRA Razor Edge Sharpness Tester (REST): This precision CNC test device is manufactured by the ISO standards approved Cutlery Association Testing Research Association (CATRA) in England. The machine actually measures how sharp an edge is by pushing a knife into calibrated silicone media until the blade edge penetrates to a certain depth, and measuring the maximum force required in Newtons (abbreviated N: 1 N is about ¼ pound). Our test results indicate that once a blade edge requires approximately 3.0 Ns to cut into the media, the edge will no longer shave and is no longer considered to be "sharp". This method provides statistically testable numerical values.
2. Edge Retention Tester (ERT): This machine is CNC controlled and uses a reciprocating system that holds the test blade in place moving the blade in the XY axis. A system of air operated cylinders and mechanical locking mechanisms lowers and raises a ¾ inch diameter manila rope in the Z axis onto the blade under approximately 50 Ns of force (about 12 lbs.) The rope is securely held in place allowing the moving blade to cut the rope. After one stroke, the depth of cut is recorded in the process computer and graphed. The length of one blade stroke is preset and the same blade section (about 2.5" long) cuts the rope repeatedly. After a set number of cuts, the blade is removed and tested on the REST machine to measure sharpness in the blade zone where the rope was being cut. This sequence is repeated until the blade is no longer sharp as measured by consistent REST readings above 3.0 N.
3. Edge Strength Tester (EST): This is a mechanical machine that has a ¼ inch stainless steel rod secured in place at an 18-degree angle to a test blade lowered onto it. Force exerted on the razor sharp blade edge can be increased to 68 pounds. Evidence of edge chipping or deformation is noted and measured.
4. Flex Test: A test used by the American Bladesmith Society to determine blade toughness and edge strength. The test involves securing a blade in a vise at a point 1/3 the blade length from the tip. The blade is bent to breakage or a 90-degree angle and then the edge is inspected for cracking or chipping. This is our only "hands-on" test but leaves no doubt about a blade's toughness and was thus used in our tests.
5. Corrosion Test: Test blades are coated with 100% Nitric Acid then immersed in salt water (fully saturated at 70 degrees F) for two weeks.

D2 is known for it's toughness and has excellent chemical elements that will alloy and create a high performance blade.

Yes, we tried a few others but found various problems, especially with the particle metallurgy steels, that were complex and numerous. While these problems may eventually be worked out, we had so many other mechanical challenges to overcome at the outset that dealing with raw material problems just didn't make sense.

The research spanned a period of 4 ½ years.

Multiple US and Foreign patents held by various Universities and corporate entities protect Friction Stir Processing and PCBN tool manufacture. "Solid State Processing of Hand-Held Knife Blades To Improve Blade Performance" was filed by Allen, Charles E.; et.al, and is Patent Pending.

More than 600 individual laboratory tests were conducted over four years, and thus, the raw data is simply too voluminous to report here. However, please see the section on "Friction Forging and Engineering a Super Blade" as data are reported there and discussed with graphs. You can also see Sorensen, C.D., Nelson, T.W., et.al. 2007. "Friction Stir Processing of D2 Tool Steel For Enhanced Blade Performance, " Friction Stir Welding And Processing IV, TMS Annual Meeting, Orlando, FL., ISBN 978-0-87339-661-5 for additional results. The pre-published paper and presentation can be found at the web site: www.byu.edu/groups/fsw

True, but none with a 65-68 RHc cutting edge and not D2. A stainless edge is important, as it will resist chemical edge degradation that has the same dulling effect on a knife-edge, as does abrasion deformation.

The entire blade is D2.

This is a bit complex. When D2 is made in the mill, the steel is alloyed with several elements such as Carbon, Vanadium, Chromium, Manganese, Molybdenum, Nickel, and Silicon at prescribed percentage ranges. When quenched under normal conditions, a percentage of the Carbon combines with the Chromium and Vanadium to form Metal Carbides. When Chromium is "locked up" in Carbides, this reduces the amount of Chromium available in the ferrite. When the Chromium in the ferrite is reduced below 12%, the steel is unable to prevent staining and rusting. This is why D2 is known as a high carbon, stain resistant but not stainless steel.

During the Friction Forging® process, some of the Chromium is freed up to go back into the ferrite. Under the heat and pressure of the spinning PCBN tool, the steel becomes plasticized sufficiently to go above transformation (eutectoid) temperature. At this temperature, Chromium carbides begin to dissolve. Both Chromium and Carbon are freed up and go into solution in the austenite when steel is in the Friction Forged® plasticized state.

Once completed, the Friction Forged zone is quenched rapidly by the surrounding steel which is "cold", i.e. room temperature. This rapid quench is sufficiently fast as to minimize any carbide formation during cooling. This essentially "freezes in" the Chromium and Carbon into the very fine Martensite grain structures. The free Chromium in the martensite makes the Friction Forged zone "Stainless". The extra carbon in solution enables higher hardness than in traditional process D2.

No, we have not changed the percentage of the elements so legally it is still D2. However we have re-distributed the way the elements combine at the molecular level-thus the corrosion proof edge and extra bump in hardness.

We bent 10 test blades with edge hardness values between 65-68 RHc to over 90 degrees with no edge cracking or chipping. This was on a blade designed to the test standard blade geometry as described by the American Bladesmith Society test. No Friction Forged® blade constructed to these geometries failed the test.

Yes, about 30 people outside the team and employees have witnessed this test.

Yes.

Well, how about this:

1. Cut 500 pieces of ¾" manila rope on the ERT CNC machine and have a CATRA REST reading of less than 3.0 Newtons; translation: will still shave.
2. Chop through a 2x4 10 times, no edge damage and will still have a CATRA REST of less than 3.0 and will still shave.
3. With one stroke, cut free-hanging rope 1.0" in diameter 6 inches or less from bottom at least 10 times and will still have CATRA reading of less than 3.0 and will still shave.
4. Bend to 90 degrees or more with no edge chip, crack, or breakage of any kind.
5. Coat blade with 100% Nitric Acid to test for corrosion proof edge. Immerse in saturated saltwater solution for two weeks.

These tests are well above those required for passing the ABS Journeyman test and thus should provide you a good indication of high performance. Ideally, we would prefer to test along side another non-Friction Forged blade made by another maker of any material of their choosing but both blades should be of the same geometry and of course each blade will be subjected to each of the tests listed above.

One of the greatest exaggerations ever told goes like this: Knife Buyer: "How does this knife hold an edge"? Knife Salesman: "Great". Knife Buyer: "Is it hard to sharpen"? Knife Salesman: "Nope, it holds a great edge and is easy to re-sharpen".

Are your red lights starting to blink? They should, because from a pure physics standpoint, a material can't be both at the same time. It's either soft, easy to dull, and easy to re-sharpen, or at the extreme end (where our blades are), very hard and very difficult to dull, and consequently they take more time to re-sharpen.

Compared to other knife blades? Yes they are, however by using an aluminum oxide 320 grit Fine India stone by Norton, you can put a beautiful razor edge back on this material without a great deal more effort than experienced with a normal premium grade steel. You can also use the diamond sharpeners but they will not leave as nice of an edge. We also recommend a few strokes on a polishing strop at the end. The Arkansas stones are just not quite hard enough to cut this material and are not recommended.

A couple of reasons. One is geometry. Thick blades are harder to sharpen than a thinner blade because you have to grind away so much material. The second is directly proportional to the blade edge hardness. High hardness means it is more resistant to abrasion and dulling. That is, the harder blade will always stay sharp a lot longer than will a softer blade. Consequently, a harder blade is more resistant to grinding and honing-sharpening. Because a normal knife blade edge has a hardness value of 58 to 61 Rockwell (RHc), and the DiamondBlade knives have edge hardness values from 65 to 68, they will resist dulling much more effectively than will other knives-they stay sharp longer-tests indicate about 10 times longer than standard best quality D2 blades-and will take more time to re-sharpen once they do eventually lose their shaving sharp edge.

You can send it back to us, for $15.00 + $10.00 shipping and for TX residence there will be a 6.25% tax added, we will refurbish and sharpen your knife. You can send a check, money order or have us call for credit card info. Please add a note with name, shipping address, phone # and instructions.
Just send to:

These blades are precision instruments that required multiple manufacturing and handcraftsmanship processes to build. They deserve to be treated as you would a fine gun.

Because the Friction Forging® process was performed on D2 steel, a stain resistant but not classed as a stainless steel, it is important you keep the blade clean and oiled or the area above the Friction Forged® zone will stain and even develop light rust. We also recommend you remove the knives from their sheaths and coat them with oil for long-term storage.

This is the undeniable "trademark" of a true Friction Forged® blade. The area approximately .375 inch above the edge has all been forged and is very hard. It is so hard, that when we use our ceramic peening process on the blade, the Friction Forged® zone cannot be peened and comes out bright and shiny.

You have several choices. Desert Ironwood: It is important to keep the Desert Ironwood handles treated periodically with a high quality oil finish to prevent moisture from entering the wood pores and to reduce the possibility of cracking. Do not use lubricating oil such as what you would use to protect the steel. A good oil finish solution is Tung oil and Linseed oil mixed in a 50/50 ratio. These oils are available from almost any paint or hardware store. You should not use pure Linseed oil as it has properties that prevent it from drying correctly and can make the handle feel "gummy" and will be prone to collect dirt. The pure Tung oil is very good for preventing moisture transfer but by itself will not provide the deep luster than you can obtain with a mixture of Linseed and Tung oil together. Coat the handle and rub to a dry luster.

Stag: Stag is one of the most beautiful and timeless handle materials but because it is porous, it tends to shrink and the surface can become dry and rough. Keep stag coated with Johnson's baby oil or coconut oil to prevent drying, shrinking, and cracking.

Micarta: Almost indestructible. Keep clean and oil around steel tang to prevent moisture from developing rust under the handle scales.

G-10, olive drab color. About the same as Micarta. Almost indestructible and treated the same as the Micarta.

Our leather sheaths are all No.1 Grade American manufactured, vegetable tanned and will provide an attractive and effective method to carry your knives. With proper care, leather can last for decades, and even though it may have a worn and used look, aging can actually enhance the character and beauty of the leather. Here are some hints on leather sheath care. If your sheath becomes wet, do not dry it over a hot surface. The leather can become hard, brittle and even crack. Allow the sheath to dry slowly in a warm, dry room. You must remove your knife from the sheath while drying and if you must carry your knife in a wet sheath while in the field, coat the blade liberally with lubricating oil or even some kind of animal fat will do until you are out of the field.

Cleaning and Preserving: Dipping the sheaths in a mixture of 20% warm saddle oil to 80% beeswax will coat the inside and outside, and seal the leather's pores. After dipping in the warm solution, wipe the sheath down, rubbing off the excess coating. This is an excellent method to help waterproof the leather. Also, there are numerous products on the market that will clean and protect leather. They include Leola, Renaissance Wax, Mink Oil, saddle soap (for cleaning only), Snow Seal, and others. Be very careful about oiling the sheath without wax in the solution. Oil can soften the leather to the point that it loses its molded shape.