CPM MagnaCut

Every Calafia, Alta, Catalina and Atri knife has a blade of CPM MagnaCut, a stainless steel designed specifically for knives. Many knifemakers consider it the best-balanced stainless knife steel ever made: it stays sharp, resists chipping and doesn't rust.

A Catalina paring knife blade in CPM MagnaCut, in process, held flat in an open hand in the workshop
An Aura California Catalina CPM MagnaCut blade in process.

Three things a blade has to do

Edge retentionStay sharpHow long the edge keeps cutting cleanly before it needs attention.
ToughnessStay wholeHow well a thin edge holds up against a bone, a hard squash or the board, without chipping.
Corrosion resistanceStay cleanHow well the blade resists rust and staining from water, salt and acidic food.

Most steels give you two of the three. Hard carbon steels hold an edge but rust. Many stainless steels resist rust but chip or dull sooner. MagnaCut was designed to do all three well.

How it does it

MagnaCut was developed by metallurgist Dr. Larrin Thomas and is made in the United States by Crucible Industries. "CPM" stands for Crucible Particle Metallurgy: the steel is made from fine powder rather than poured in large ingots, which keeps its structure even and fine.

In most stainless steels, part of the chromium forms large chromium carbides. Those carbides take chromium away from rust protection and make a thin edge more likely to chip. MagnaCut is balanced so they don't form. The chromium stays in the steel, where it protects against rust, and the cutting work is done by very fine, very hard vanadium and niobium carbides.

What the testing shows

  • In standardized CATRA slicing tests, MagnaCut held its edge about as well as CPM S35VN and CPM 4V, two steels well regarded for edge retention.
  • Its toughness is in the range of non-stainless tool steels such as CPM 4V, well above earlier powder stainless steels.
  • In a saltwater test, MagnaCut showed no visible rust after 72 hours, while most of the steels tested alongside it rusted.

Results published by Dr. Larrin Thomas from his own testing.

In your kitchen

  • The edge lasts. A few passes on a leather strop keeps it sharp day to day. When it needs more, sharpen on a stone at 15 degrees.
  • Hand wash and dry. MagnaCut resists rust better than almost any knife steel, but no fine knife belongs in a dishwasher.
  • Use a wood or plastic board. Glass, stone and ceramic boards dull any edge.

Aurochs steak knives

Our Aurochs steak knives use Sandvik 14C28N, a nitrogen-enriched Swedish stainless steel.

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