Wood species
Sycamore wood
Sycamore is a hardwood (Platanus occidentalis). At 12% moisture content it has a Janka hardness of 770 lbf (3,425 N) and it weighs about 34 lb/ft³ (549 kg/m³), 2.9 lb (1.3 kg) per board foot.
Also called: American sycamore, buttonwood.
Key numbers
- Janka hardness, 12% MC
- 770 lbf (3,425 N)
- Green: 610 lbf (2,713 N)
- Weight at 12% MC
- 34 lb/ft³ (549 kg/m³)
- 2.9 lb per board foot
- Specific gravity (oven-dry weight)
- 0.49 at 12% MC volume
- 0.46 on green volume
- Shrinkage, green to oven-dry
- 8.4% tangential
- Radial 5.0%, volumetric 14.1%
One source: USDA Forest Products Laboratory, the authority for species properties it measured
Why: Measured by the USDA Forest Products Laboratory; sycamore's density is worked from its specific gravity with the Handbook's own equation.
How much sycamore moves
A 12 in wide flatsawn board of American sycamore that goes from 6% to 12% moisture content swells about 0.21 in (about 7/32 in, 5.4 mm). Quartersawn, the same board moves about 0.12 in (about 1/8 in, 3.1 mm). Flatsawn faces move 1.7 times as much as quartersawn ones, because the wood shrinks 8.4% around the growth rings but only 5.0% across them.
Worked with the Wood Handbook's dimensional change coefficients for American sycamore (Table 13-5: 0.00297 tangential, 0.00172 radial per 1% change in moisture content), which hold between 6% and 14%. Individual boards vary: the Handbook gives shrinkage a coefficient of variation of about 15% (p. 4-11).
Color, grain and working
- Color
- Reddish-brown heartwood and light sapwood 2 to 3 in. wide.
- Grain and texture
- Fine texture with interlocked grain.
- Working and character
- Moderately heavy, hard, stiff and strong with good shock resistance, and high shrinkage while drying.
- Uses
- Furniture, boxes (especially small food containers), pallets, flooring, handles and butcher blocks.
Adapted in our own words from the Wood Handbook, Chapter 2, p. 2-10.
Strength
Bending strength is the modulus of rupture (MOR); stiffness is the modulus of elasticity (MOE). Clear, straight-grained samples of American sycamore tested by the Forest Products Laboratory (Wood Handbook Table 5-3b). Knots and cross grain make lumber weaker than these clear samples (Handbook Chapter 5).
| Property | Green | 12% MC |
|---|---|---|
| Bending strength (MOR) | 6,500 psi (45 MPa) | 10,000 psi (69 MPa) |
| Stiffness (MOE) | 1,060,000 psi (7.3 GPa) | 1,420,000 psi (9.8 GPa) |
| Crushing strength (compression parallel to grain) | 2,920 psi (20 MPa) | 5,380 psi (37 MPa) |
| Compression perpendicular to grain | 360 psi (2 MPa) | 700 psi (5 MPa) |
| Shear parallel to grain | 1,000 psi (7 MPa) | 1,470 psi (10 MPa) |
| Tension perpendicular to grain | 630 psi (4 MPa) | 720 psi (5 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 USDA Forest Products Laboratory measured American sycamore at 770 lbf of side hardness at 12% moisture content, on clear, straight-grained samples (Wood Handbook Table 5-3b).
One source: USDA Forest Products Laboratory, the authority for species properties it measured , 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, the authority for species properties it measured , sources [1]
So
Density at 12% is water's density × specific gravity × (1 + 0.12) (Handbook Eq. 4-14): 62.43 × 0.49 × 1.12.
Arithmetic: exact by definition , sources [1]
The number
About 34 lb/ft³, or 2.9 lb per board foot (1/12 ft³), at 12% moisture content.
Arithmetic: exact by definition
Sources