Black Walnut VS African Mahogany
- Stronger in bending (MOR 101.0 vs 78.6 MPa)
- Lighter (0.52 vs 0.55 g/cm³)
- Solid choice where its profile fits the project
Visual comparison
Winner by category
There isn't one universally best wood — there's a best wood for each purpose.
| Category | Winner |
|---|---|
| Durability | Tie |
| Stability | Tie |
| Hardness | African Mahogany |
| Strength (MOR) | Black Walnut |
| Stiffness (MOE) | Black Walnut |
| Flame spread | Tie |
| Machining ease | Tie |
| Lightness | African Mahogany |
Engineering data
| Property | Black Walnut | African Mahogany |
|---|---|---|
| Janka Hardness | 1010WD lbf | 1070WD lbf |
| Density | 0.55FPL g/cm³ | 0.52FPL g/cm³ |
| MOE | 11.6FPL GPa | 9.7FPL GPa |
| MOR | 101.0FPL MPa | 78.6FPL MPa |
| Durability | Class 3 Moderately Durable | Class 3 Moderately Durable |
| Stability | Excellent | Excellent |
| Fire (E84) | Class B indicative | Class B indicative |
| Radial Shrink | 5.5WD % | 3WD % |
| Tangential Shrink | 7.8WD % | 5WD % |
| T/R Ratio | 1.42 | 1.67 |
Figures carry the same source status as the species pages they come from — verified where cited, indicative where marked.
Best for
| Application | Recommended | Suitability |
|---|---|---|
| Outdoor decking / pergola | 🥇 Black Walnut | ★★★★☆ |
| Exterior cladding | 🥇 African Mahogany | ★★★★☆ |
| Flooring / wear surfaces | 🥇 African Mahogany | ★★★☆☆ |
| Furniture / interior joinery | 🥇 Black Walnut | ★★★★☆ |
| Structural / load-bearing | 🥇 Black Walnut | ★★★☆☆ |
Advantages & limitations
Black Walnut
Advantages relative to African Mahogany
- MOR is 101 MPa vs 79 MPa, about 28% higher
- MOE is 11.6 GPa vs 9.7 GPa, about 20% higher
Limitations relative to African Mahogany
- Radial shrinkage 5.5% vs 3.0% and tangential 7.8% vs 5.0% — greater movement on both axes
African Mahogany
Advantages relative to Black Walnut
- Radial shrinkage 3.0% vs 5.5% and tangential 5.0% vs 7.8% — much less movement in service
Limitations relative to Black Walnut
- MOR is 79 MPa vs 101 MPa, about 22% lower
- MOE is 9.7 GPa vs 11.6 GPa, about 16% lower
Recommendation
Choose Black Walnut if…
- The application depends on shock resistance — gunstocks are the exemplar use
- Higher bending strength and stiffness matter for the piece
Choose African Mahogany if…
- Wide panels or flat surfaces must stay flat — panelling, cabinet doors, or veneer applications
- The application is boat and ship building — mahogany's documented exterior use
Frequently asked questions
Which is more durable, Black Walnut or African Mahogany?
Neither — both carry the same EN 350 rating (Class 3, Moderately Durable). For outdoor work the separation is movement, not decay: African Mahogany moves 5.0% tangentially against 7.8%, which decides board width and fixing spacing more than the durability class does.
Which wood is better for outdoor use?
Both are EN 350 Class 3, and tangential movement runs 7.8% for Black Walnut against 5.0% for African Mahogany — close enough that decay resistance will not choose between them, and African Mahogany holds its dimension marginally better. Hardness is effectively level (1,010 vs 1,070 lbf), so choose on supply, length and price.
Is Black Walnut harder than African Mahogany?
No — African Mahogany is harder (Janka 1070 vs 1010 lbf).