Titanium knives?

J

Johan

Joined
Oct 12, 1999
Messages
631
Hello all! I've been thinking about getting a titanium bladed knife (the price is really good) and I was wondering if someone out there could answer two of my questions:

1. How does titanium take an edge?

2. Being non-ferrous, does that mean that metal detectors can't detect it? No, I'm not planning to smuggle it through a detector, I'm just curious.

Thanks in advance.

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"Better to reign in Hell, than serve in Heav'n"
John Milton
There are only two types of people; those who understand this, and those who think they do.
 
I have a couple of titanium knives. I don't know how they hold the edge, but the original edges are quite sharp. One main purpose of a titanium blade is to be able to pass metal detectors unnoticed. You have to be sure that the handle, screws, etc. are also nondetectable metal.
 
Can you give me examples of Titanium knives that I might look for?

Thanks

Brandon

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I've got the schizophrenic blues
No I don't
Yes I do...
 
Be careful, modern metal detectors just do that: detect ANY metal. They do not look for magnetisms but work with "eddy currents" present in any conducting material, titanium included.
So watch your step.
Boker (Germany) has just announced kitchen knives made of a titanium/titanium carbide compound (still: hush hush) which "should" hold an edge even better than "steel".
At "high prices". I'll tell as soon as I see such a "beast".
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D.T. UTZINGER
 
Some of the earlier Benchmade 970's had titanium blades with carbide(?) coatings right at the edge that was also intended to increase edge longevity. I've handled a couple, but never owned one, so I'm not sure how effective it was.

One advantage of non-ferrous blades is the lessened likelyhood of danger around some magnetically-detonated ordinance. Frankly, I hope never to be in a position to want a titanium knife for that particular reason.

And as stated above, many metal detectors will recognize the eddy currents of any metallic object as it passes through its magnetic field. Run a search for earlier posts concerning this subject. It's been discussed several times at length with more detail than I can possibly remember at this point.

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Don LeHue

Rome did not create a great empire by having meetings...they did it by killing all those who opposed them.
 
Beta titanium (the type used by Mission Knives) generates virtually no eddy currents, thus is safe around magnetic or capacitance detonated ordnance. Further, it will not set off a metal detector if it is of the usual type, which indeed monitor the generation of eddy currents.

Note that ferromagnetism is NOT required to be detected. Thus Cu, Al and Co will all be detected, although most people do not think of them as magnetic, as most people think ferromagnetism when someone says magnetic (i.e. will a magnet stick to it = ferromagnetism, NOT magnetism). Nor is a pre-existing magnetic field required for detection. One somewhat disreputable company was selling stainless steel belt buckle knives a while ago, stating that they weren't detectable, as they had been degaussed (demagnetized). This is poppycock.

Newer metal detectors, which monitor the millimeter wavelength radiation generated by the human body, will monitor ANY object being carried on the body, as well as the body itself. This is why it has generated a lot of controversy. Remember the old rule about the smallest discernable detail being roughly the size of the wavelength being used to measure the object. One millimeter is VERY fine detail, for detectors.

BM did indeed make a Ti bladed knife, in the 970 series, which had a Tantalum carbide coating on one side, to give at least a slight degree of edge holding. It didn't work well at all; it was best described as a poorly sharpened pry bar.

A Ti bladed knife is a waste of money unless you are fooling around with things that go bang. If you wish corrosion resistance and good edge holding, you want Talonite (r) or Stellite (r). Kit Carson has made many U-2 dive knives of both materials over the past decade, and has never had one returned for blade breakage.

Hope this helps, Walt
 
Hey guys, thought I'd pass along a few things I've learned recently concerning titanium blades. One important point to remember is that just like steel, titanium comes in a variety of different alloys. The most common type of titanium used in knife production is known as 6Al/4V. Most of the titanium handles, bolsters,liners and liner locks that we see on both production and custom knives use this particular alloy. While an incredibly tough and resilient alloy (and an outstanding choice for these above uses), 6Al/4v titanium cannot be made hard enough to provide a truly effective cutting edge. From time to time you will run across a knife with one of these blades, but understand that in most cases they were really not intended to be daily users.

As Don pointed out, Benchmade got around this shortcoming of 6Al/4V by making a titanium blade which carried an edge that I believe was actually a tungsten carbide insert (vice coating). There may also be a couple of custom makers still offering blades like this although I can't remember any off the top of my head.

Another solution was developed by the folks at Mission Knife and Tool. Rather than stick with 6Al/4V, they developed a process to use a beta alloy titanium (often simply referred to as Beta Ti) for knife blades. The main advantage of Beta Ti over 6Al/4V is that Beta Ti can be hardened to an HRC of near 50 which significantly improves edge holding characteristics while sacrificing none of the other inherent benefits of titanium (i.e. non-magnetic and nearly corrosion proof). I own a Mission MPK and find both it's edge retention and ease of sharpening to be quite good. Brandon- I can recommend any of the knives in the Mission line that appeals to you.

Bottom line Johan, when considering a purchase, make sure you know what specific alloy you're dealing with, and then determine whether or not it's performance meets your specific needs. For a daily user, I'd definitely recommend going with the Beta Ti. For a lightweight, last resort type of defensive weapon, 6Al/4V might be fine.

BTW, I can't agree more with ZUT&ZUT regarding airport metal detectors. Think of how many times that pocketful of non-ferrous coins has set off an airport metal detector.

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Semper Fi
 
Thanks everbody, especially Bronco-you answered all my questions! As for the metal detector question, it really was just curiosity.
smile.gif


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"Better to reign in Hell, than serve in Heav'n"
John Milton
There are only two types of people; those who understand this, and those who think they do.
 
No problemo Johan, I'm glad I could help.

Hi Walt. Hope all is well up in NoCal. I don't normally find myself disagreeing with you, but I think it's a little harsh to say that Mission's knives are a waste of money except when used in an EOD setting.

I find them to be very useful and capable when I'm diving. It's kind of nice to be able to toss your knife into your dive bag full of wet salty gear and not have to worry about it. They may not have the edge retention of Talonite (which is also nearly corrosion proof), but I still think their utility in this setting hardly qualifies them as a waste of money.

In my extended backpacking ventures where every ounce of weight is critical, a titanium knife makes it possible to bring along the strength and durability of a fixed blade at a weight that is less than that of many folders. The light weight also makes titanium blades good fighters in the opinion of some, especially considering how well they endure the forces generated by stabbing impacts.

Admittedly titanium is nobody's first choice for a chopper due to its light weight, but in extremely cold environments titanium will continue chopping long after steel blades have become too brittle to use.

Finally, I'll be the first to admit that a knife is not a prybar. But in those rare situations where such abuses can't be avoided I think a titanium blade would be my first choice.

Again Doc, I respect your opinions quite a bit and I'm not spoiling for a fight, but I think Mission's knives have far more utility than just as an EOD tool and I figured I should back that opinion up.

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Semper Fi
 
Walt; Alpha-Beta Titanium alloys (ie, 6-4) and Beta alloys (mission grade), are complete different "animals". In my opinion, the "lumping" of all titanium alloys into one pot and thinking that they all perform the same has been the one main reason for titanium's slow acceptance. Did you know that there are over 100 different titanium alloys in the world at any one given time? Almost as many grades as steel? If I were to use the same analogy, then I could say that steel knives are crap because they do not hold an edge. I have a US Divers scuba knife made out of 304 stainless and it won't hold an edge, therefore, all steel knives don't hold an edge. This is the same scenario we see everyday with regards to titanium alloy. We have 3X the alloy, yes THREE TIMES the alloy content in our titanium than Benchmade used in their Emerson folder. Looks like we might be using a different grade? You bet we are. We can heat treat ours.

I want to also point out for buyer beware. There are other companies out there claiming to use BetaTitanium in their dive knives - I won't mention OceanMaster's name. We had our lab test the grade of titanium they are using, and guess what...it's NOT beta titanium, in fact, I hardness tested it - it wasn't even heat treated - dead soft at about RC28. In fact, in a recent ad of theirs, they claim to be the only company making titanium bladed knives! Great marketing, lie through your teeth to sell your product.

Bronco; thanks for your kind words and support. I too use a titanium knife when I dive. I use the MPD and it is a fantastic little dive knife. Since Tim Wegner now makes the sheaths for us - he has added his universal attachment rig to it and I have it attached to the left BC vest adjustment strap. Easy to get to, deploy and reattach. Next time you are in the area, let's do a Catalina dive!

Thanks again and take care.
Sincerely,
Rick

bc_mpd1.jpg

bc_mpd2.jpg

bc_mpd3.jpg
 
I just wanted to comment on the corrosion resistance of the Titanium and Talonite alloys. For all intents and purposes that you may expect such a knife to see, these alloys will not corrode at all. Let me put it this way. If your hand will survive unscathed, so will the blade. Only a few specific acids will attack and corrode titanium and this is not something alot of people will run into. I don't know what will attack Talonite, but it won't rust at all when exposed to saltwater, blood and other corrosive fluids. Same goes for Titanium as far as I know. I am sure that Missionknives can verify that. Or if I am wrong atleast clarify it for us all.
The BM titanium knife had a Tungsten Carbide coating, not a Tantalum carbide, and if I remember it correctly, it was a sintered-on coating and not an insert. It was supposed to add longevity to the edge of the titanium blade, and did succeed at doing so. The main problem was that the edge was rather coarse and I doubt you could shave with it. As I recall it was recommended not to sharpen the knife at all. Maybe Benchmade could clear this up for us if one of their employees are lurking.
Well enouch of me ranting. I am just looking forward to hearing more of the new alloy that Mission is working on!!!

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Regards
Joshua "Kage" Calvert

"Move like Water, strike like Thunder..."
 
Bronco, Rick, thank you very much for your first hand knowledge on this subject. I will admit that it has been many many years since I have done any diving (and I won't comment on what POS knife I had then
wink.gif
).

Rick; to answer your question, yes, I do know that there are many alloys of Ti available. I even know where to find information about these alloys:
http://www.principalmetals.com/

Further, I correctly identified the alloy which you use (well, at least its' generic type; beta Ti, which is an allomorph of Ti if IRC). So, while not a metallurgist or knife maker (and never have played either one on TV
wink.gif
), I feel that I did not incorrectly characterize your knives.

While your knives have considerable merit, and enjoy a deservedly good reputation, I still do not see any advantage over a Haynes alloy except for reduced magnetic signature. I do remain open minded on this matter, however.

In addition, are there not some peculiar corrosion problems with Ti? I seem to remember that the SR-71 mechanics could not use ordinary cadmium plated tools, as the Cd would corrode the Ti. I seem to remember halogens corrode Ti as well, but obviously ionized Cl- is not a problem, otherwise salt water would corrode Ti dive knives. This might apply only to elemental halogens.

What do you say to a practical, real world test? It so happens that Mike Turber has a Kit Carson Talonite (r) small U-2 dive knife of mine. Mike is also a scuba diver. Would you care to send Mike one of your knives and have him test it side by side with the U-2?

This could generate some useful data, helpful to the forumites.

I await your gracious reply, Walt
 
Carniflex; you are correct, at least I think so. I contacted BM, and they said that the coating (and it is a coating, not an insert), was tungsten carbide - tantalum alloy.

Now, I am confused as to what this means. Tungsten carbide is usually considered to be a cobalt matrix with tungsten carbide grains in it. By contrast, the Haynes alloys (Stellite (r), Talonite (r), etc.) are considered to be alloys of Co-Cr-W (and sometimes Mo), but they are not the carbides in a Co matrix, but the carbides of Co, Cr, W and Mo are present, and are what give it its' hardness.

Haynes alloys are usually formed from two groups of elements in the VII series (iron , ruthenium, osmium, hassium, or cobalt, rhodium, iridium, meitnerium). Tantalum, however, is in the V-B series, considerably distant from the Haynes series, but Ta is the element one atomic number lower than W; thus tantalum and tungsten are adjacent elements. Further, Ta is in the vanadium, niobium, hanium series (V-B), and vanadium is definitely a carbide former. The VI-B series also contains carbide formers, Cr, Mo, and W. Thus, it would not surprise me that Ta is a carbide former. Why it would be alloyed with W and C is unknown to me.

I e-mailed Les de Asis about this, hopefully he can shed some light on this matter.

Walt
 
DonL and Walt, my apologies for doubting you guys on the method used by BM to apply the coating to their 970(SBT?). Had the right material but wrong attachment method.

Rick, I recently purchased an MPS for my diving duties and mention it now only because I wanted to add my endorsement for the outstanding sheaths you've commissioned from Tim Wegner. It's the best Kydex sheath I own. First class all the way. I'd love to bring it along and go lobster hunting with you sometime.

Doc Welch, thanks for jumping back in on this one. I too would love to see an impartial head-to-head comparison between a like sized Beta Ti and Talonite blade. I own no Talonite blades at present, but like the concept very much and am anxious to give it a try. I've been holding off only to let some more real world testing data filter in.

It is obvious, therefore, that I can't give any direct personal comparisons between the two substances. However, based upon what I think I know about Talonite, I would imagine that Beta Ti would be preferable to Talonite in the following scenarios:

--Where weight is a critical concern. Again, I'll use the example of someone on an extended backpacking trip. Chopping is the only obvious weak link in Beta Ti's profile here. But, that having been said, I must admit that I don't know if that makes Talonite a better choice for chopping duties. I really haven't seen too many Talonite blades built for the purpose of being choppers. This is not to say that there aren't any, only that I haven't seen them. A majority of the Talonite models I see from folks like Rob Simonich, Allen Blade and Neil Blackwood appear to be of a smaller utility/hunter style.

--For use in a fighter. Here too titanium's lightweight is an advantage over Talonite (which actually has more mass than steel). Beta Ti is also incredibly resilient and enjoys a higher tensile strength than Talonite. Thus it is better able to withstand the forces of stabbing impacts.

--For use in extreme cold weather environments. Beta Ti is unaffected at temperatures well below those which steel (and I'll assume Talonite) are extremely brittle and delicate.

--For use in abusive environments (either intentional or unintentional). If faced with a scenario where my knife might potentially be subjected to abusive prying type forces, again the increased tensile strength of Beta Ti would be a definite advantage over Talonite.

Please let me know if I've misrepresented any of the facts concerning Talonite or if you feel any of my claims are unfounded. I hope Rick or John can speak to your question regarding the effects of cadmium on Beta Ti. I've also heard stories of the SR-71 mechs' tools being cadmium free and wonder if this is a legitimate concern for us.

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Semper Fi
 
Bronco; no problem on the insert vs. coating issue concerning the BM 970ST. There have been several knives with inserts of various kinds. You were probably thinking of one of them.

About the other issues you brought up:

Weight; no doubt about it, Talonite (r) is more massive than steel, much more massive than titanium. If weight is a concern, go with Ti; it is lots lighter.

Chopping; I tend to agree with you. Both titanium and Talonite (r) would be rather poor choices. Ti because of its' light weight and perhaps its' questionable edge holding, Talonite (r) because of its' cost and perhaps questionable edge holding as well. A Ti or Talonite (r) Kukhri would be a foolish item. Unless it were in the Neiman-Marcus Christmas Catalog.
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Fighter; hmmm... don't really know. True, the lighter mass of Ti would make you faster, but with the decreased mass comes decreased momentum (mass x velocity).

Regarding the ability to withstand impact and abusive environments, Talonite (r) was designed for jet engine turbine blades, for US Navy jets. Enough said? Further, Kit Carson has been making U-2 dive knives out of Haynes alloys for over 10 years, and they have flat points so that they can be (and are) used for prying. Not one has been returned due to blade failure.

Regarding cold weather, here is what the Carbide Processors' site has to say:

Cold weather applications:
This alloy does not show any significant changes in strength or use at reasonable operating temperatures. This alloy is used successfully in jet engines that are stationed in the arctic.
Click to expand...

Of course, both Ti and Talonite (r) are stable at high temperatures far above whatever any of us would use them at.

Thanks for bringing these interesting topics up, Bronco.

Walt

 
I recently got a Mission MPK in Beta Ti. It can be made sharp enough to readily shave hair off my arms. I could not tell if a steel knife would have done better.

It is too new for me to say anything about edge retention.


Is MV as important when sharp objects are involved? The Mission knives has as much mass as a lightweight folder. The mass of the arm and hand holding the knife probably makes a larger contribution to mass than the knife.

Will
 
Doc, I enjoy bringing up these topics only half as much as I enjoy your well reasoned responses.

I think it will be super if Talonite's cold weather performance in a knife blade proves to be as good as its performance in turbine blades. Such an outcome will just give me one more reason to give Allen or Neil a ring. I'd only caution that, although turbine blades certainly are subjected to some incredible stresses, these stresses generally build gradually as turbine rpms increase and the engine comes to temperature. A subzero knife blade edge impacting a frozen branch imparts a different type of force which the good folks at Carbide Processors may or may not be taking into account.

It sounds kind of ridiculous to propose that whacking a material on a branch could be more destructive than running it in a jet engine at 1100 degrees, but I can remember when Ruger learned a variation of that very same lesson after trying to adapt a titanium turbine blade alloy for use in the cylinders of their new line of lightweight revolvers.

I don't know that anyone from CP monitors this forum, but it would be great to get some of their input on this issue. Or we could wait until the mercury starts dipping below zero where Cliff Stamp lives. That should be in about what, 6 weeks.
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Will, I'd like to hear from some of our accomplished martial artists regarding the handling characteristics of lighter vs. heavier weight knife blades and see where their preferences lie.

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Semper Fi
 
1. My goodness, I have never seen Dr, Welch so brilliant, clear and well organized. It must be the good Washington wine he is drinking lately.

2. Magnetism - depending on how you define it everything has a magnetic property or susceptibility even if it is negative or neutral. E.G. Titanium +153, Copper -5 or -6, lead -23, etc. Gadolinium at +185,000 is about the highest. It also makes a huge difference how you use it. Potassium ferrocyanide is -130 and Potassium ferricyanide is +2290. (CRC Handbook of chemistry & Physics 74th edition).

In a certain sense detecting positive, negative or neutral magnetic susceptibility is like riding in a car and detecting high or low spots in the road. Airport detectors detect differences either positive or negative. I do not know if the titanium knives can be made truly undetectable. I would be willing to bet that there will always be some way to detect a knife, even a titanium knife.

3. Talonite (r) and corrosion. We developed Talonite (r) for knives because of the type of success we had with it in sawmills. Woods such as cedar, spruce and hemlock are particularly high in acids. Saw tips can get well over 1,000F from friction in the cut and there is huge amount of wear cutting a very fibrous material such as wood. In this case we have a Talonite (r) saw tip making millions of cuts (e.g. 5,000 - 10,000 rpm) at very high temperature in a high acid environment before it starts to get dull.

4. As for temperature sensitivity it will cut frozen knotty pine at sub-zero temperatures.

5. An impartial head-to-head comparison between a like sized Beta Ti and Talonite (r) blade - we will donate the Talonite (r) if the test is comprehensive (I suspect that each knife will have different strengths and I would like to know what they are), if the testing is done to reflect the purposes for which the knives were made (brutality for the sake of brutality doesn't tell me much) and (a really tough one) if each material is shaped and handled so as to bring out its best properties. (No, I am not sure how this would work but I know it is important.)

6. Rob built a survival knife out of Talonite (r) that was featured in a magazine article I think in Blade. It did very well as a chopper.

7. Tensile strength - I apologize but I don't understand what is meant here. We use 'tensile' to mean strength as related to the amount of force required to pull something apart. I am not sure how this applies unless we are going to stretch the two metals until they elongate and / or separate. Even in that case I do not understand the relevance.

8. Re: mass in combat If it were used to pierce I am not sure mass makes much difference (think of an epee) and in a slashing attack I would think that more mass would transmit more energy with the obvious drawback of being harder to recover.

9. We think that a diamond coated titanium knife is possible and would be really cool. However it is about $3,000 to run the chamber a single time, which makes development though experimentation pretty expensive.

10. Talonite (r) cost. I just got my Cuda from Camillus and now I own a Talonite (r) knife. (Every knife maker was too backed up and put the real customers first - quite properly and the original Talonite (r) knife went to the original Talon.) Anyway, it is a lot of knife for the money. We also tried chopping 2x4 with it. It works - not my first choice but you could cut enough saplings for a lean-to pretty readily.

Tom walz
Carbide Processors

Talonite ®
 
Tom tensile strength is relevant because of the other properties it implies, not because of the quantity it specifically measures. The very low tensile strength of Talonite is readily evident by how easy it is to roll the edge, dent it, or put a bend in the blade itself. It is also why Rod Simonich states to keep the edges thick so as to prevent failures such as Steve Harvey described. From what I have heard from Rick at Mission, their Ti should be stronger and more durable. I have *no* direct experience with it however. I am sure in time that Will Kwan will have something valuable to say in this regard.

As for edge holding during chopping, wear resistance is of very low importance here, basically none. Strength and toughness however are critical. I have broken blades apart and bent other up while chopping on wood, yet the edges (or pieces of) were still very sharp. I don't think that is a desirable ability. It would be far more sensible to have the edges go blunt a little faster with the blade staying in its original shape. As for the low weight of Mission's Ti and chopping, that simply means you alter the geometry, make the blade wider and/or longer. It would make an interesting choice for a machete.

-Cliff

[This message has been edited by Cliff Stamp (edited 06-06-2000).]
 
Tom,
Thanks for your input and for jumping into the fray. Gotta say, diamond coated titanium sounds awful interesting. I completely understand how hard it would be to justify such R&D costs, but haven't you been dying to give it a shot just once? Inquiring minds want to know.

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Semper Fi
 
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