Bubinga
Guibourtia spp.
Bubinga measures 2,690 lbf on the Janka scale, 109% harder than northern red oak.
- Of the 155 woods, only five are stronger for their weight, nine harder and nine stronger in bending.
- Only four woods sit further above the density–hardness trend: a specific gravity of 0.71 would point to about 2,040 lbf.
U.S. hardwoodsU.S. softwoodsImported woodsNorthern red oak
Six measures
BubingaImported woods medianOther woods
Janka hardness
2,690 lbf11,966 N10th hardest of 15510th of 65 imported woods; 107% above the imported woods median240 lbf3,680 lbfBending strength
22,600 psi155.8 MPa10th strongest of 15535% above the imported woods median4,300 psi29,900 psiStiffness
2.48 M psi17.1 GPa14th stiffest of 1550.54 M psi4.06 M psiDensity
0.7117th heaviest of 1550.250.96Cupping tendency
1.4519th lowest of 1551.092.90Shrinkage across the face
8.4%radial 5.8%59th highest of 1553.5%12.7%
For its weight: strength-to-weight 31,831 psi (6th of 155).
How much it moves
The two directions move almost alike (T/R 1.45), so flatsawn and quartersawn boards differ by only 0.16 in.
0.50 in.
off a 6-inch flatsawn board, green to oven-dry
- Tangential
- 8.4%
- Radial
- 5.8%
- Volume
- 14.2%
- T/R ratio
- 1.45 (19th most stable of 155)
End view, shrinkage drawn 3× life size.
Closest substitutes
Woods of similar hardness
The eight nearest on the Janka scale, lbf.
Laboratory values
Its most unusual laboratory figure is shear strength: the highest of the 154 woods with a published value.
| Property | Dry, 12% MC | Metric, 12% MC |
|---|---|---|
| Shear parallel to grain | 3,110psi | 21.4MPa |
| Modulus of rupture | 22,600psi | 155.8MPa |
| Side hardness | 2,690lbf | 11,966N |
| Compression parallel to grain | 10,500psi | 72.4MPa |
| Modulus of elasticity | 2.48M psi | 17.1GPa |
The handbook publishes only values at 12% moisture content for this wood; green values and some tests are not given.
Wood Handbook Table 5-5b, Table 4-4. Data & method · Guides