Lam.CoS

Lam.CoS is the signature blade material of Swedish knifemaker Fällkniven. Strictly speaking, it isn’t a single steel but a three-layer laminate. Here are the key facts:

Origin: “Lam.CoS” stands for “Laminated Cobalt Special Steel.” Fällkniven is a family business from Boden in northern Sweden, founded in 1984. Its blades are made in Japan. In 1998 the company switched from ATS-34 to laminated VG-10. Around 2011 it added the cobalt special steel CoS, which according to Fällkniven cost roughly 50–60% more than VG-10 at the time. Today Lam.CoS blades are found in the F1 (the survival knife of Swedish Air Force pilots since 1995), the X series, the Pro series, and the Modern Bowie, among others.

Construction: The blade is built like a sandwich: 420J2 – CoS – 420J2. A hard CoS core forms the cutting edge. It is clad on both sides with 420J2, a low-carbon, highly rust-resistant and tough steel. Look closely and you can see a fine line just above the edge where the layers meet.

Composition: The CoS core consists of the following main elements:
Carbon (C): approx. 1.05–1.1%
Chromium (Cr): approx. 16%
Molybdenum (Mo): approx. 1.5%
Cobalt (Co): approx. 2.5%
Vanadium (V): approx. 0.25–0.3%
Tungsten (W): approx. 0.3%

Of interest to collectors: chemically, CoS is a close relative of VG-10. It contains more chromium, molybdenum and especially cobalt, plus a little tungsten. The steel is used exclusively in Fällkniven knives.

Hardness: The core is around 60 HRC, ranging from 59 to 61 HRC depending on the model.

Edge Retention: No independent CATRA figures are available yet. According to Fällkniven, CoS holds an edge better than the laminated VG-10 it used before. That’s why the Pro models, for example, were switched from VG-10 to CoS. It falls short of powder steels such as Elmax or Fällkniven’s own 3G.

Corrosion Resistance: Very good. The core has around 16% chromium, and the 420J2 outer layers are virtually rust-free. That makes Lam.CoS well suited to wet conditions and outdoor use.

Practical Takeaway: The idea behind Lam.CoS is a combination that is otherwise hard to achieve: a hard, sharp edge from the core and tough outer layers that absorb bending and lateral stress. Fällkniven states that the laminated blade is at least 20% stronger than a solid stainless blade. Combined with the brand’s typical convex grind, this makes the knives especially robust for outdoor and survival use. In everyday use, the blade resharpens well, barely rusts, and tolerates rougher work.