Wood species
Ovangkol wood
Ovangkol is a hardwood (Guibourtia ehie). It weighs about 50 lb/ft³ (809 kg/m³), 4.2 lb (1.91 kg) per board foot.
Also called: ehie.
Key numbers
- Janka hardness, 12% MC
- Not measured
- Weight at 12% MC
- 50 lb/ft³ (809 kg/m³)
- 4.2 lb per board foot
- Specific gravity (oven-dry weight)
- 0.67 on green volume
- Shrinkage, green to oven-dry
- 8.2% tangential
- Radial 4.5%, volumetric 12.0%
One source: USDA Forest Products Laboratory, collected from the world literature (its Tables 5-5 and 4-4)
Why: From the USDA Wood Handbook, which collected these values from the world literature; ovangkol's density is worked from its specific gravity with the Handbook's own equations.
How much ovangkol moves
A 12 in wide flatsawn board of ovangkol that goes from 6% to 12% moisture content swells about 0.21 in (about 7/32 in, 5.3 mm). Quartersawn, the same board moves about 0.11 in (about 1/8 in, 2.8 mm). Flatsawn faces move 1.8 times as much as quartersawn ones, because the wood shrinks 8.2% around the growth rings but only 4.5% across them.
Worked from the Wood Handbook's shrinkage values (Table 4-4) with its Eq. 13-4; the Handbook gives no movement coefficients for imported woods. Individual boards vary: the Handbook gives shrinkage a coefficient of variation of about 15% (p. 4-11).
Color, grain and working
- Color
- Golden brown to dark brown with gray to almost black stripes.
- Grain and texture
- Moderately coarse texture.
- Working and character
- Moderately hard and heavy but works well with hand and machine tools; moderately durable. Drying can be difficult but goes well with care.
- Uses
- Turnery, flooring, furniture parts, cabinetwork and decorative veneer.
Adapted in our own words from the Wood Handbook, Chapter 2, p. 2-22.
Strength
Bending strength is the modulus of rupture (MOR); stiffness is the modulus of elasticity (MOE). Values for ovangkol from Wood Handbook Table 5-5b (p. 5-24), which the Handbook says were collected from the world literature, on clear, straight-grained specimens. Knots and cross grain make lumber weaker than these clear samples (Handbook Chapter 5).
| Property | Green | 12% MC |
|---|---|---|
| Bending strength (MOR) | — | 16,900 psi (117 MPa) |
| Stiffness (MOE) | — | 2,560,000 psi (17.7 GPa) |
| Crushing strength (compression parallel to grain) | — | 8,300 psi (57 MPa) |
| Shear parallel to grain | — | — |
A dash means the Handbook prints no value; none is filled in.
Dust and health
- Wood dust is classed as carcinogenic to humans (Group 1) by the International Agency for Research on Cancer, chiefly for cancers of the nose and sinuses.
- NIOSH recommends keeping wood dust exposure to 1 mg/m³ of total dust, as quoted in OSHA's sawmill guidance.
This is what the named authorities publish, not medical advice.
Compare with
Why these numbers
Why these numbers?
The situation
The Wood Handbook prints no side hardness for ovangkol (Table 5-5b, p. 5-24 shows "—"), so none is given here.
One source: USDA Forest Products Laboratory, collected from the world literature (its Tables 5-5 and 4-4) , sources [1]
What that means
Side hardness (Janka) is the load needed to press a 0.444 in (11.28 mm) steel ball halfway into the wood across the grain; a higher number dents less (Handbook p. 5-5).
One source: USDA Forest Products Laboratory, collected from the world literature (its Tables 5-5 and 4-4) , sources [1]
So
The Handbook gives only the green specific gravity (0.67) for ovangkol, so it is moved to 12% with the volumetric shrinkage of 12% (Eqs. 4-9 and 4-11), then multiplied by water's density and 1.12 (Eq. 4-14).
Arithmetic: exact by definition , sources [1]
The number
About 50 lb/ft³, or 4.2 lb per board foot (1/12 ft³), at 12% moisture content.
Arithmetic: exact by definition
Sources