Tropical wood · Tropical America
Tonka wood
Tonka (Dipteryx odorata, family Leguminosae) is a tropical timber from tropical America. Dry, its Janka hardness is 3,540 lbf (15,747 N), and air-dry it weighs about 62–81 lb/ft³ (993–1,297 kg/m³). The figures are from the USDA Forest Products Laboratory's Tropical Timbers of the World, pp. 131–132.
Other names, by country: Almendro (Costa Rica, Panama), Sarrapia (Venezuela, Colombia), Cumarú (Brazil), Charapilla, Cumarut (Peru).
Key numbers
- Janka hardness, dry
- 3,540 lbf (15,747 N)
- Green: 2,200 lbf (9,786 N)
- As printed: “Janka side hardness 2,200 lb for green material and 3,540 lb at 12% moisture content.”
- Air-dry density
- 62–81 lb/ft³ (993–1,297 kg/m³)
- Basic specific gravity
- 0.80–0.91 oven-dry weight, green volume
- As printed: “Basic specific gravity (ovendry weight/green volume) ranges from 0.80 to 0.91; air-dry density 62 to 81 pcf.”
- Shrinkage, green to oven-dry
- 7.6% tangential
- Radial 5.0%, volumetric 12.0%
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 3 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 |
|---|---|---|---|
| Green | 19,290 psi (133 MPa) | 2.69 million psi (18.5 GPa) | 9,020 psi (62 MPa) |
| 12% MC | 27,270 psi (188 MPa) | 3.03 million psi (20.9 GPa) | 13,720 psi (95 MPa) |
| 12% MC | 22,400 psi (154 MPa) | 3.01 million psi (20.8 GPa) | 13,200 psi (91 MPa) |
A dash means the sheet prints no value; none is filled in.
What the data sheet says
- Color, grain and texture
- Fresh heartwood is reddish-brown or purplish-brown with light yellowish-brown or purplish streaks; upon exposure gradually becomes uniform light brown or yellowish-brown. Sapwood is distinct, narrow, yellowish-brown. Luster rather low to medium; texture fine; grain interlocked; waxy or oily feel; taste not distinctive but may have a vanilla-like or rancid odor.
- Working properties
- The wood is difficult to saw and bore; where severely interlocked grain is not present, the wood planes to a smooth surface. Because of its high density and oily nature, the wood glues poorly.
- Durability
- The timbers have a reputation for being very durable. Laboratory tests also show the heartwood to be very durable in resistance to both brown-rot and white-rot fungi. The wood has excellent weathering characteristics.
- Uses
- Heavy construction, cogs and shafts, barge and dock fenders, flooring, railroad crossties, pulpmill equipment, tool handles, bearings, turnery. A substitute for lignumvitae.
- Where it grows
- The Guianas, Venezuela, Colombia, and the Amazon region of Brazil; reaches its best development on well-drained gravelly or sandy sites. Cultivated in many areas for the tonka beans used as a flavoring.
Quoted from Tropical Timbers of the World, pp. 131–132, a USDA Forest Products Laboratory work in the public domain.
Work it out for your project
- Rank woods for flooring with the species picker
Weigh tonka against other woods on hardness, weight, movement and color, every figure from the Wood Handbook.