Thursday, December 27, 2012

Up Next: SM 100

We all imagine the perfect blade steel.  It would be as hard and hold an edge as long as M4 or ZDP-189.  It would be very durable and chip resistant like Busse's INFI steel.  It would be highly corrosion resistant like H1.  Nothing can do all of these things though.  Blade steel, the old maxim goes, is about trade offs.

At a certain price, however, this is no longer true.

There is a metal out there (note I did not write STEEL; this material lacks iron, the necessary element that makes steel steel) that does all of this.  It was invented in the 1960s by the Navel Ordinance Laboratory and has only recently become "cheap enough" to be used in cutlery blades.  I say "cheap enough" because even now it is fabulously expensive.

The specs are pretty amazing: HRc between 64-66, virtually corrosion (not just rust) proof, and not simple durable, but it can return to its original shape from any position with a bit of heat.  That sounds like a blade steel out of science fiction, but it is not.  It is a material known by many names (with slight differences between each).  The material is made of nickel and titanium called Nitinol.  There are other formulations of nickel titanium in additional to Nitinol, but Nitinol also known as Nitinol 60 is the formulation used in cutlery.  Nitinol 60 is being sold in cutlery markets by Summit Materials as "SM 100."

Nitinol 60 (which stands for NIckel TItanium Naval Ordinance Laboratory) was invented by William Buehler and Fredrick Wang in 1962.  It was developed in the Navy's lab to be rust proof, non magnetic, and most importantly, highly resistant to bending and stress.  Here is an amazing demonstration of the unique stress resistance of Nitinol, a property called superelasticity:


You heard him correctly, it will do this many hundreds of times.  Nickel titanium, which includes Nitinol 60/SM 100, is the more resistant to stress than any other known metal.

Originally it was used in disarming devices, bearings, and medical stints implanted in the body.  It was very strong, very light, and corrosion proof (according to NASA) making it a PERFECT material for implants in the body.  Eventually concerns about the nickel content have moved Nitinol into other areas, cutlery for example.

Here is a SM 100 Terry McGinnis Custom (image courtesy of Summit Materials):


The gold/bronze color is a consequence of heat treating the metal and you can work it back to silver or leave it.  I personally really like the look of the blade in gold/bronze.  It would make an awesome pairing with some Lightning Strike Carbon Fiber. 

The overall combination of attributes makes Nitinol 60/SM 100 pretty much the ideal blade steel.  It seems to break the rule about having to balance toughness, rust resistance, and hardness.  There have been a few people that think that 66 HRc automatically makes for a chippy blade, but there is so little of it out there that it is hard to say for certain.  Then you realize that there is another drawback, one that does not chart so well on the steel attribute triangle--price.  SM 100 is insanely expensive.  I went to price out a SM 100 blade, 2.5 inch flipper and it was around $900.  The SnG that Strider did in SM 100 sold for around $2,000.  At that price, it may as well be gold.

Right now SM 100 is a material only a few makers use.  Strider did a very small run of blades in SM 100.  Terry McGinnis, as you can see above, did a run with the material.  Ferrum Forge, a small custom maker, also uses SM 100.  His rates are a much more realistic than those of both Strider and McGinnis, but his reputation is just starting to spread.  He even has a small SM 100 Ti framelock folder up right now for $600, a shocking bargain, especially when you start to price out blades made of this stuff.  One particularly inspired design Elliot made in SM 100 was a folding fillet knife.  Something as lean and as flexible as a fillet knife is perhaps the ideal application for a superelastic metal.

I'd love to see one of the big three (Spyderco, Benchmade, and Kershaw) do a blade in SM 100.  A ZT flipper made of the stuff would absolutely rock and I can see folks going nuts over an Spyderco Mule in SM 100.  Either way, this stuff is the next big thing in blade steels.  Hell it is so cutting edge it is not even a steel.      

2 comments:

  1. Sure the extra corrosion resistant might be an added plus, but I'm not sure I see any real benefit for this stuff. Most HSS and high alloyed steels are plenty tough for normal chores. Additionally after HT, SM-100 doesn't retain any shape memory alloy abilities.

    As far as edge retention goes on knives, there has been no real third-party (well none that I have seen and it seems that mostly collectors are eating this stuff up) or even first-party data (the data on SM's site is with bearings). Even with an HT SM-100 bearing being 3x more wear resistant than a 440C bearing, I'm not sure how this would translate in terms of edge retention. I have a feeling that high carbide volume steels are still going to be leaps and bounds better in edge retention than SM-100.

    I wish I could have gotten one of the Dwyer DB in this material but alas the half dozen or so that were made are most likely forever in the safe of several collector never to see the light of day.

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  2. If you are interested I have a playlist on SM-100 with knives from a number of makers.

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