Calavara Cutlery El Patron Sm100 / Nitinol
Convex Grind, very sharp. One of the best blade materials and grind combinations for a super sharp blade on a hard use knife! SM100 is the most unique blade material that is used today. It is many times more expensive than steel, costing at least 10x as much. SM100 also is much more difficult for a maker to grind and machine into a working knife. As such SM100 is made in small amounts by the manufacturer and only used by knife makers on special projects. The base price of these knives exceeds knife makers’ normal table prices, due to extra material cost and the intense labor to grind this super metal. It is quite worth the extra cost when you have a blade that has a history of NASA engineering!!
About SM100 or Nitinol:
There hasn’t been a revolution in knife materials since it was discovered that adding excess carbon to iron produced steel. Sure evolution has occurred, but things really aren’t that different than they were 200 years ago – until now.
Well, over the past several years we’ve developed our patented SM-100™ material to be that exact material revolution. For practical purposes, there will now be three main classes of knife materials – steels, ceramics, and SM-100.
SM-100 was originally developed for bearing and wear components for the United States Space Program, and it quickly became evident that we were onto something really important and relevant to the knife community. Along with lots of help from Duane Dwyer of Strider Knives fame, we worked tirelessly on prototypes and processing sequences to arrive at where we are today, which is the ability to provide you with one of the absolute best knife making materials.
So, what makes SM-100 such a phenomenal knife material?
Well, for starters, it will never rust or corrode for you. In fact NASA publically calls it “Corrosion proof”. And we’re not talking about corrosion proof like stainless is supposed to be, we’re talking about you can leave SM-100 at the bottom of the ocean for 100-years and the knife will look as good as it did the day you dropped it overboard.
An important point to make here is that the high hardness that SM-100 achieves is through-thickness hardness – in other words there are no coatings to chip off or surface heat treatments to break through.
On top of the lower friction pointed out in the plot below, notice that the SM-100 has twice the life of the 440C (in bearing applications). The left of the plot shows some titanium results, which as expected do not wear well at all, but are of course quite corrosion resistant. So anytime you wish you could combine the corrosion resistance of titanium with superb wear resistance, call on SM-100. Now, we often get asked how all our bearing data relates to knives, well you’d have to ask our growing base of satisfied customers about that.
In addition to the inherent material properties that SM-100 brings to the wear resistance discussion, our patented processing route also improves wear resistance by imparting a super-fine grain microstructure as seen in this micrograph. This type of microstructure ensures that the proper distribution of the all-important hardening phases is found along the entire length of the edge.
By contrast, we’ve seen other processing sequences result in elongated grains with segregated phases that result in decreased wear resistance and ultimately poor edge retention.
Another benefit of SM-100 knives is the lower coefficient of friction when compared to steels. This means easier cutting (less force required) and a cleaner and safer working environment in general – whether you’re working in the kitchen or in the middle of the jungle.
SM-100 is non-magnetic meaning that it can be used as field tools where ferrous metals pose a safety risk such as is the case with mine probes or ordnance tools.
An extremely unique feature of SM-100 is the ability to electrolyticly color your knives with custom colors and patterns. We are still in the early stages of exploiting this feature, so expect to see more information here in the future.
Compression behavior of hot rolled plus hardened SM-100. Note: The maximum stress level is limited by test fixtures, not the specimen.
NASA conducted common compression tests to determine at what load SM-100 would fail – only this time their machine couldn’t go high enough to cause failure!
As you can see in the plot, once the initial load was relieved, the material strained about 1% and then took on a superelastic behavior. This has two major positive implications for the knife world:
If your knife or tool experiences an unplanned load shock to the system, SM-100 will only strain 1%, likely saving catastrophic failure and probably going unnoticed.
More interestingly, however, was NASA’s finding that after the 1% strain introduction, SM-100 becomes superelastic. This means that if you impart the strain in your knife prior to service use (and there are numerous ways to do this), you have a component on your hands that can absorb a tremendous amount of stress without failure – something the steel family only wishes it could claim.
The extremely intelligent folks at NASA Glenn uncovered yet another amazing property for SM-100, namely the Damage Threshold Load Capacity. The basic findings mean that a SM-100 solution won’t corrode or rust, and can absorb an order of magnitude more load before failure over other competing materials. There is literally no material that can compete with SM-100.
These finding have enormous practical implications for knives and other tools that are used in harsh environments. Due to a high Modell Number, SM-100 can absorb the intense loading that is imparted when a knife is used in an unplanned for situation (and we’ve all done that many, many times).
NASA best summed up the results of this data while talking about bearings (but it is equally applicable to knives) by stating “The combination of high hardness, moderate elastic modulus, large recoverable strain, low density, and intrinsic corrosion immunity provide a path to bearings largely impervious to shock load damage.”