Wood species
Goncalo alves wood
Goncalo alves is a hardwood (Astronium graveolens). At 12% moisture content it has a Janka hardness of 2,160 lbf (9,608 N) and it weighs about 62 lb/ft³ (1,001 kg/m³), 5.2 lb (2.36 kg) per board foot.
Also called: gonçalo alves.
Key numbers
- Janka hardness, 12% MC
- 2,160 lbf (9,608 N)
- Green: 1,910 lbf (8,496 N)
- Weight at 12% MC
- 62 lb/ft³ (1,001 kg/m³)
- 5.2 lb per board foot
- Specific gravity (oven-dry weight)
- 0.84 on green volume
- Shrinkage, green to oven-dry
- 7.6% tangential
- Radial 4.0%, volumetric 10.0%
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; goncalo alves's density is worked from its specific gravity with the Handbook's own equations.
How much goncalo alves moves
A 12 in wide flatsawn board of goncalo alves that goes from 6% to 12% moisture content swells about 0.19 in (about 3/16 in, 4.9 mm). Quartersawn, the same board moves about 0.1 in (about 3/32 in, 2.5 mm). Flatsawn faces move 1.9 times as much as quartersawn ones, because the wood shrinks 7.6% around the growth rings but only 4.0% 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
- Russet, orange-brown or reddish brown with dark stripes, turning brown or red with nearly black stripes; grayish white sapwood.
- Grain and texture
- Fine to medium, uniform texture; grain straight to interlocked and wavy.
- Working and character
- Very dense and strong. Turns readily, finishes very smooth and takes a high polish; the dense dark areas can be hard to glue. Very durable.
- Uses
- Archery bows, billiard cue butts, brush backs, cutlery handles, turning and carving. It is imported mainly for its looks.
Adapted in our own words from the Wood Handbook, Chapter 2, p. 2-24.
Strength
Bending strength is the modulus of rupture (MOR); stiffness is the modulus of elasticity (MOE). Values for goncalo alves from Wood Handbook Table 5-5b (p. 5-22), 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) | 12,100 psi (83 MPa) | 16,600 psi (114 MPa) |
| Stiffness (MOE) | 1,940,000 psi (13.4 GPa) | 2,230,000 psi (15.4 GPa) |
| Crushing strength (compression parallel to grain) | 6,580 psi (45 MPa) | 10,320 psi (71 MPa) |
| Shear parallel to grain | 1,760 psi (12 MPa) | 1,960 psi (14 MPa) |
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 2,160 lbf of side hardness at 12% moisture content for goncalo alves, a value it says was collected from the world literature (Table 5-5b, p. 5-22).
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 (0.84) for goncalo alves, so it is moved to 12% with the volumetric shrinkage of 10% (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 62 lb/ft³, or 5.2 lb per board foot (1/12 ft³), at 12% moisture content.
Arithmetic: exact by definition
Sources