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MagnaMax favors abrasive slicing where wear dulls the edge; original MagnaCut offers more resistance to chips and cracks. Both have a corrosion rating of 9.5 in Dr. Larrin Thomas's framework, so the choice comes down to the cutting you have in mind.
Performance Ratings
Dr. Larrin Thomas of Knife Steel Nerds has kindly allowed us to share his ratings here.
The toughness score of 7 is for original Crucible MagnaCut. In written feedback to KnifeInformer, Dr. Thomas provided a toughness rating of 8.5 for Erasteel MagnaCut; his January 2026 testing explains the differences between the two versions. This table uses the original version.
| Property | CPM MagnaCut | MagnaMax |
|---|---|---|
| Abrasive edge retention | ||
| Toughness | ||
| Corrosion resistance |
Heat treatment, hardness and geometry affect actual knives.
When MagnaMax Offers the More Useful Tradeoff
MagnaMax's 7.5 abrasive edge-retention rating sits above MagnaCut's 5. That is relevant to repeated abrasive slicing, such as breaking down cardboard. It is not a percentage improvement or a promise about days between sharpenings. A thin grind can also make slicing easier, so consider edge geometry alongside wear resistance. Niagara describes MagnaMax's wear-focused design.
When MagnaCut Offers the More Useful Tradeoff
Original MagnaCut is rated 7 for toughness, compared with MagnaMax at 6. That favors MagnaCut when resistance to chips and cracks is especially important, though edge thickness and sharpening angle still affect how much support the edge has. Neither steel makes twisting a thin blade through a stubborn cut a good idea.
Our MagnaCut steel profile explains its design, care and the differences between production versions.
Corrosion Resistance Is a Tie in This Framework
Both are rated 9.5, so corrosion alone does not separate them here. It also does not make either whole knife rustproof. The blade finish, hardware, pivot and storage conditions still matter. Clean off residue and dry the knife after wet use. Thomas's later MagnaMax testing includes corrosion tests of the final material; early prototype reports need their own context.
Read the MagnaMax steel profile for more on care and early prototype differences.
Composition
Our steel composition guide explains the elements and how to read these values.
CPM MagnaCut: Niagara typical composition, mass %; selected elements, not a batch analysis. Niagara Specialty Metals: CPM MagnaCut.
MagnaMax: Reported composition from Larrin Thomas’s July 2026 table, mass %; not a producer specification or batch analysis. Knife Steel Nerds: stainless steel composition table (July 2026).
| Element | CPM MagnaCut | MagnaMax |
|---|---|---|
| Carbon (C) | 1.15% | 2.05% |
| Chromium (Cr) | 10.7% | 10.7% |
| Vanadium (V) | 4% | 8% |
| Molybdenum (Mo) | 2% | 2% |
| Niobium (Nb) | 2% | 2.5% |
| Nitrogen (N) | 0.2% | 0.2% |
Compare Two Knife Steels
Sources and Update Notes
- Dr. Larrin Thomas: rating framework
- Dr. Larrin Thomas: MagnaMax development · Properties and prototype context. MagnaMax ratings of 7.5 / 6 / 9.5 follow direct feedback from Dr. Thomas dated October 9, 2026.
- Dr. Larrin Thomas: final MagnaMax heat-treatment testing
- Niagara: MagnaMax technical overview
- Niagara: original CPM MagnaCut composition
- Dr. Larrin Thomas: Erasteel MagnaCut testing · Research comparing the two versions; the numeric 8.5 rating was supplied separately in written feedback.
- Dr. Larrin Thomas: published steel composition table · MagnaMax composition from the embedded stainless-steel composition table, published after the January introduction withheld the full formula. Reported alloy values, not a certified batch analysis.
- Dr. Larrin Thomas: MagnaMax industrial and custom heat treatment · Research comparing industrial and custom heat treatments.
