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.

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