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CPM 3V puts toughness first; MagnaCut gives up some of that toughness for much higher corrosion resistance. Their abrasive edge-retention ratings are close. For an outdoor knife, the useful choice is between the extra resistance to chipping offered by 3V and the easier rust care offered by MagnaCut.
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 | CPM 3V | CPM MagnaCut |
|---|---|---|
| Abrasive edge retention | ||
| Toughness | ||
| Corrosion resistance |
Heat treatment, hardness and geometry affect actual knives.
Where 3V Earns Its Place
3V rates 9 for toughness, compared with 7 for original MagnaCut. That makes 3V worth considering for a fixed blade where resistance to edge damage is a high priority. It is not a guarantee that a thin 3V knife can safely do the work of a larger tool.
For wood carving or other controlled cuts, the blade’s thickness behind the edge and its handle can matter more to comfort and cutting ability than the difference in scores. Choose the complete knife for the work, then use the steel comparison to refine that choice.
See our CPM 3V steel profile for more on its properties and care.
What Changes in Wet Conditions?
MagnaCut rates 9.5 for corrosion resistance; 3V rates 5.5 and is not stainless. If you expect rain, wet vegetation or a blade that is difficult to dry promptly, MagnaCut reduces the care burden. We would favor it for a general outdoor knife when rust resistance matters more than maximizing toughness.
A coating on a 3V blade can protect covered surfaces, but the sharpened edge remains exposed. Drying and protective care still matter. Conversely, MagnaCut’s stainless rating is not a reason to leave salt or food residue on the knife.
See our CPM MagnaCut steel profile for more on its properties and care.
Edge Retention Is a Close Call
MagnaCut rates 5 for abrasive edge retention and 3V 4.5. We would treat that as a small published difference, not the deciding argument for an upgrade. It does not establish that every MagnaCut knife will cut longer than every 3V knife.
Both contain hard vanadium carbides. Diamond or cubic boron nitride (CBN) abrasives are useful options for sharpening, particularly for edge repairs. The ratings do not measure sharpening time or burr removal.
Check Which MagnaCut Version You Are Comparing
The table uses original MagnaCut. Dr. Thomas supplied an 8.5 toughness rating for Erasteel MagnaCut in written feedback, which brings its toughness rating much closer to 3V’s 9. If the maker confirms Erasteel material, the argument for choosing 3V solely for its toughness is narrower.
Do not assume a current listing identifies the production version unless the maker says so. For the actual purchase, we would choose 3V when toughness is the priority and regular rust care is acceptable, or MagnaCut when a stainless blade better fits the way the knife will be carried and used.
Composition
Our steel composition guide explains what the elements do and how to read these values.
CPM 3V: Selected nominal/typical values, mass %; not a batch certificate or complete analysis. Niagara Specialty Metals: CPM 3V.
CPM MagnaCut: Niagara typical composition, mass %; selected elements, not a batch analysis. Niagara Specialty Metals: CPM MagnaCut.
| Element | CPM 3V | CPM MagnaCut |
|---|---|---|
| Carbon (C) | 0.8% | 1.15% |
| Manganese (Mn) | 0.3% | Not listed |
| Silicon (Si) | 1% | Not listed |
| Chromium (Cr) | 7.5% | 10.7% |
| Molybdenum (Mo) | 1.3% | 2% |
| Vanadium (V) | 2.75% | 4% |
| 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 and their limits.
- Niagara Specialty Metals: CPM 3V · Typical chemistry and the steel’s emphasis on resistance to chipping.
- Niagara Specialty Metals: CPM MagnaCut · Typical composition and material properties.
- Dr. Larrin Thomas: Erasteel and original MagnaCut · Research comparing the two versions; the numeric 8.5 rating was supplied separately in written feedback.
