Tropical wood · Southeast Asia and Oceania
Silky-oak wood
Silky-oak (Grevillea robusta, family Proteaceae) is a tropical timber from Southeast Asia and Oceania. Dry, its Janka hardness is 840 lbf (3,737 N), and air-dry it weighs about 38 lb/ft³ (609 kg/m³). The figures are from the USDA Forest Products Laboratory's Tropical Timbers of the World, pp. 657–658.
Other names, by country: Southern silky-oak (Australia), Kawilia (Tanganyika), Lacewood (USA).
Key numbers
- Janka hardness, dry
- 840 lbf (3,737 N)
- As printed: “Janka side hardness 840 lb for dry material.”
- Air-dry density
- 38 lb/ft³ (609 kg/m³)
- Basic specific gravity
- 0.51 oven-dry weight, green volume
- As printed: “Basic specific gravity (ovendry weight/green volume) 0.51; air-dry density 38 pcf.”
- Shrinkage, green to oven-dry
- 7.7% tangential
- Radial 2.7%
One source: USDA Forest Products Laboratory, Tropical Timbers of the World (Chudnoff, 1979 edition), the only published source read for this wood
Strength
Bending strength is the modulus of rupture (MOR); stiffness is the modulus of elasticity (MOE); crushing strength is compression parallel to the grain. The sheet collects these from published tests: it prints 2 data sets, from different tests and sources, so they can differ widely; all are shown, in the sheet's order, each at the moisture content printed beside it, never restated as 12%.
| Moisture | Bending strength (MOR) | Stiffness (MOE) | Crushing strength |
|---|---|---|---|
| 12% MC | 13,400 psi (92 MPa) | — | — |
| 12% MC | 8,460 psi (58 MPa) | 1.11 million psi (7.7 GPa) | 5,060 psi (35 MPa) |
A dash means the sheet prints no value; none is filled in.
What the data sheet says
- Color, grain and texture
- Heartwood pale pinkish-brown becoming yellow-brown on exposure; sapwood cream-colored, moderately well defined. Texture medium to coarse; grain straight to wavy; lustrous; because of large rays, figure is prominent on quartered faces. Some people develop skin rash when working green or dry wood.
- Working properties
- The wood works well with hand and machine tools and dresses smoothly; has been rated very high in all-around machinability.
- Durability
- Heartwood is rated as moderately resistant to attack by decay fungi and termites; sapwood is perishable.
- Uses
- Joinery, furniture, parquet flooring, decorative veneers, turnery, light construction work.
- Where it grows
- Native to eastern Australia but planted extensively as a shade tree for coffee and tea plantations and as an ornamental in tropical and subtropical regions.
Quoted from Tropical Timbers of the World, pp. 657–658, a USDA Forest Products Laboratory work in the public domain.
Work it out for your project
- Rank woods for furniture with the species picker
Weigh silky-oak against other woods on hardness, weight, movement and color, every figure from the Wood Handbook.