African mahogany
Khaya spp.
African mahogany measures 830 lbf on the Janka scale, 36% softer than northern red oak.
- Of the 155 woods, only five shrink less across the face and six shrink less through the thickness.
- American elm and western larch have exactly the same Janka figure.
U.S. hardwoodsU.S. softwoodsImported woodsNorthern red oak
Six measures
African mahoganyImported woods medianOther woods
Shrinkage across the face
4.5%radial 2.5%6th lowest of 15543% below the imported woods median3.5%12.7%Stiffness
1.40 M psi9.7 GPa37th most flexible of 15530% below the imported woods median0.54 M psi4.06 M psiDensity
0.4245th lightest of 15531% below the imported woods median0.250.96Bending strength
10,700 psi73.8 MPa45th weakest of 15536% below the imported woods median4,300 psi29,900 psiJanka hardness
830 lbf3,692 N65th softest of 15548th of 65 imported woods; 36% below the imported woods median240 lbf3,680 lbfCupping tendency
1.8074th lowest of 1551.092.90
How much it moves
Its face shrinkage of 4.5% is in the lowest quarter of the list, with an ordinary T/R ratio of 1.80.
0.27 in.
off a 6-inch flatsawn board, green to oven-dry; quartersawn 0.15 in.
- Tangential
- 4.5%
- Radial
- 2.5%
- Volume
- 8.8%
- T/R ratio
- 1.80 (74th most stable of 155)
End view, shrinkage drawn 3× life size.
Laboratory values
| Property | Green | Dry, 12% MC | Change when dried | Metric, 12% MC |
|---|---|---|---|---|
| Work to maximum load | 7.10in-lbf/in³ | 8.30in-lbf/in³ | +17% | 57.2kJ/m³ |
| Modulus of elasticity | 1.15M psi | 1.40M psi | +22% | 9.65GPa |
| Modulus of rupture | 7,400psi | 10,700psi | +45% | 73.8MPa |
| Side hardness | 640lbf | 830lbf | +30% | 3,692N |
| Compression parallel to grain | 3,730psi | 6,460psi | +73% | 44.5MPa |
| Shear parallel to grain | 931psi | 1,500psi | +61% | 10.3MPa |
Wood Handbook Table 5-5b, Table 4-4. Data & method · Guides