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MagnaCut brings more abrasive edge retention and corrosion resistance than 420HC, but 420HC retains the higher toughness rating. MagnaCut is an appealing broad-performance choice, while 420HC can still be a sensible material in a knife that fits the job and budget.
Performance Ratings
For the science, we turn to Dr. Larrin Thomas of Knife Steel Nerds, who 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 | 420HC | CPM MagnaCut |
|---|---|---|
| Abrasive edge retention | ||
| Toughness | ||
| Corrosion resistance |
Heat treatment, hardness and geometry affect actual knives.
MagnaCut Has Greater Abrasive Edge Retention
MagnaCut rates 5 for abrasive edge retention and 420HC 2.5. We would favor MagnaCut when wear from repeated cutting is a meaningful limitation.
The rating is not a physical cutting-time ratio. Do not turn the numbers into a promise of twice as many cuts.
Our 420HC steel profile explains its properties and care in more detail.
420HC Has the Higher Toughness Score
420HC rates 9 for toughness and original MagnaCut 7. MagnaCut is therefore not an improvement in every measured property.
The Erasteel MagnaCut update is separate from the original rating used here. Check the production version before applying a different figure.
Our MAGNACUT steel profile explains its properties and care in more detail.
MagnaCut Adds Corrosion Margin
MagnaCut rates 9.5 for corrosion resistance against 420HC at 8. Both are stainless, but MagnaCut offers more rated margin around moisture.
That is a useful benefit for wet carry. It does not establish the corrosion resistance of the handle hardware or replace routine cleaning.
Is the Upgrade Useful to You?
We would choose MagnaCut for frequent cutting and wet conditions when the knife and price suit you. We would keep 420HC in consideration for its toughness and a well-suited design.
If your 420HC knife already handles occasional tasks well, there is no urgent need to replace it. Upgrade for a benefit that matters in your use.
Composition
Our steel composition guide explains the elements and the differences between reported values, ranges and limits.
420HC: Cleveland-Cliffs typical 420HC composition, mass %. P, S and Ni are labeled Max in the table; its footnote says these typical values are not specification limits or a universal grade certificate. Cleveland-Cliffs: Martensitic Stainless Steel Comparator.
CPM MagnaCut: Niagara typical composition, mass %; selected elements, not a batch analysis. Niagara Specialty Metals: CPM MagnaCut.
| Element | 420HC | CPM MagnaCut |
|---|---|---|
| Carbon (C) | 0.42% | 1.15% |
| Manganese (Mn) | 0.4% | Not listed |
| Phosphorus (P) | ≤0.04% | Not listed |
| Sulfur (S) | ≤0.01% | Not listed |
| Silicon (Si) | 0.5% | Not listed |
| Chromium (Cr) | 12.8% | 10.7% |
| Nickel (Ni) | ≤0.5% | Not listed |
| Vanadium (V) | Not listed | 4% |
| Molybdenum (Mo) | Not listed | 2% |
| Niobium (Nb) | Not listed | 2% |
| Nitrogen (N) | Not listed | 0.2% |
Compare Two Knife Steels
Sources and Update Notes
- Dr. Larrin Thomas: knife steel ratings · Property ratings; the scores describe steels rather than individual finished knives.
- Cleveland-Cliffs: Martensitic Stainless Steel Comparator
- Niagara Specialty Metals: CPM MagnaCut
